MYELODYSPLASTIC SYNDROME (MDS)

DEFINITION AND PATHOPHYSIOLOGY

MDS is a group of clonal bone marrow disorders characterized by ineffective hematopoiesis, dysplasia in one or more myeloid cell lines, peripheral cytopenias, and potential progression to AML in approximately 20–30% of cases. MDS is considered a form of blood cancer. The four key pathophysiologic mechanisms are:

• maturation arrest,
• ineffective hematopoiesis,
• increased apoptosis of hematopoietic precursors, and
• immunological abnormalities.

Apoptosis is more prominent in early MDS, while maturation block dominates as the disease transforms toward leukemia.

CAUSES AND RISK FACTORS

MDS may be primary (de novo, idiopathic) or secondary. Secondary MDS arises from prior chemotherapy (alkylating agents, topoisomerase II inhibitors), radiation therapy, environmental toxin exposure (e.g., benzene), or inherited bone marrow failure syndromes (e.g., Fanconi anemia, Diamond-Blackfan anemia). MDS primarily affects adults over 60 years of age. Genetic mutations frequently involved include TP53, TET2, ASXL1, SF3B1, and DNMT3A.

CLINICAL PRESENTATION

Symptoms result from cytopenias: fatigue and pallor from anemia, recurrent infections and fever from neutropenia, and bleeding, bruising, or petechiae from thrombocytopenia. Some patients are completely asymptomatic at diagnosis.

DIAGNOSIS

Diagnosis requires integration of the following: CBC with differential, peripheral smear showing dysplastic features such as hypogranular neutrophils and oval macrocytes, bone marrow biopsy showing dysplasia in one or more myeloid lineages and blast count below 20%, cytogenetics showing common abnormalities including del(5q), del(7q), monosomy 7, trisomy 8, and complex karyotypes, and molecular studies to assess mutations for prognostication and targeted therapy. Risk stratification uses the IPSS-R (Revised International Prognostic Scoring System).

RISK STRATIFICATION (IPSS-R)

TREATMENT: LOW-RISK MDS

First-line treatment is chosen based on the clinical scenario:

Key rules for low-risk MDS:

• Lenalidomide is only appropriate if del(5q) is confirmed — it is less effective or potentially harmful without this abnormality. In a Phase II study, 83% of del(5q) patients responded vs. 57% with normal karyotype.
• Luspatercept is a TGF-β ligand trap that promotes late-stage erythroid maturation and is used after ESA failure in patients with ring sideroblasts.
• Immunosuppressive therapy (ATG + cyclosporine) is best for patients under 60 years old, with hypocellular marrow, HLA-DR15 positive, or PNH clones; response rate is ~30–40%.
• Decitabine and azacitidine are NOT used in low-risk MDS unless all other agents have failed.
• Allogeneic SCT is NOT standard for low-risk MDS. G-CSF alone is not clearly indicated; it may be used to augment ESA response. Eltrombopag has no established role in MDS.

TREATMENT: HIGH-RISK MDS

• First-line: Hypomethylating agents (HMAs). Azacitidine (preferred): SubQ or IV for 7 days every 28 days; proven to improve overall survival in the AZA-001 trial. Decitabine: IV over 5 days; alternative when azacitidine is not tolerated. Mechanism: Both are DNA methyltransferase inhibitors that reverse abnormal gene silencing, restoring normal cell differentiation and survival. A minimum of 4–6 cycles must be completed before declaring treatment failure, as responses may be delayed.
• Allogeneic HSCT is the only potentially curative option. Eligibility criteria: ECOG performance status ≤ 2, IPSS-R intermediate-2 or high-risk, available donor, and minimal comorbidities assessed by the HCT-CI index. No role for radiation therapy or autologous HSCT in MDS. Autologous HSCT is contraindicated because the diseased marrow produces inadequate stem cells to collect.

HMA-refractory disease options in order of preference: clinical trials (first recommendation), venetoclax + azacitidine, IDH1/2 inhibitors if mutation is present, and palliative and supportive care.

FULL TREATMENT SUMMARY BY RISK GROUP

TARGETED THERAPIES AND MUTATIONS

ANEMIA MANAGEMENT AND SUPPORTIVE CARE

RBC transfusions are used as needed. ESAs (epoetin alfa or darbepoetin alfa) are used in low-risk MDS with symptomatic anemia when EPO is below 500 mU/mL and transfusion burden is low.
Iron chelation therapy:
start when ferritin exceeds 1000 ng/mL, transfusion burden reaches 20–25 RBC units, and expected survival is greater than 1 year.
Agents: deferasirox (oral) or deferoxamine (IV/SubQ). Discontinue exogenous iron supplements and ascorbic acid (ascorbic acid increases iron absorption and should be stopped in transfusion-related iron overload).

HMA TOXICITY MONITORING

• Myelosuppression: Monitor CBC weekly during early cycles. Hold therapy if ANC falls below 0.5 x 10⁹/L or platelets fall below 25 x 10⁹/L. G-CSF may be used selectively for neutropenic fever.
• GI effects: nausea, vomiting, and constipation — manage with prophylactic antiemetics such as ondansetron.
• Injection site reactions: rotate sites and use topical corticosteroids if needed.

RESPONSE ASSESSMENT (IWG CRITERIA)

Treatment response in MDS is evaluated across all four of the following dimensions: hematologic improvement (HI) meaning improved hemoglobin, platelets, or ANC;
complete remission (CR) meaning normal counts, less than 5% marrow blasts, no dysplasia;
partial remission (PR) meaning at least 50% reduction in blast percentage; and cytogenetic response and alteration of disease progression and quality of life.

MDS vs. APLASTIC ANEMIA

HIGH-YIELD EXAM PEARLS — MDS

• Diagnosis: MDS is a clonal bone marrow disorder with ineffective hematopoiesis and dysplasia in one or more myeloid lines. Diagnose with CBC, bone marrow biopsy, cytogenetics, and molecular studies. Common cytogenetic abnormalities: del(5q), del(7q), monosomy 7, trisomy 8, complex karyotype.
• Low-risk treatment decision tree:
  • EPO < 500 and low transfusion burden → ESA ± G-CSF.
  • Del(5q) → lenalidomide.
  • Ring sideroblasts + SF3B1 + EPO > 500 or ESA failure → luspatercept.
  • Hypoplastic MDS → ATG + cyclosporine (NOT epoetin). Lenalidomide only if del(5q) confirmed.
• High-risk treatment:
  • First-line → azacitidine (preferred HMA). Minimum 4–6 cycles before declaring failure.
  • Only curative option → allogeneic HSCT.
  • HMA-refractory → clinical trial first, then venetoclax + azacitidine or IDH inhibitors.
• Iron overload: Ferritin > 1000 + ≥ 20–25 transfusions + survival > 1 year → start iron chelation. Stop iron supplements and ascorbic acid. Use deferasirox (oral) or deferoxamine (IV/SubQ).
• Key mutations: TP53 = complex karyotype, poor prognosis, therapy-resistant. IDH1 → ivosidenib. IDH2 → enasidenib. SF3B1 → luspatercept.
• Prognosis: Low-risk → median survival > 5 years. High-risk → median survival ~1–2 years. Response assessment uses all four IWG criteria: hematologic improvement, cytogenetic response, disease progression, and quality of life.

ACUTE PROMYELOCYTIC LEUKEMIA (APL)

DEFINITION AND PATHOPHYSIOLOGY

APL is a subtype of AML (FAB classification: AML-M3). The defining mutation is t(15;17)(q24;q21), which fuses the PML gene on chromosome 15 with the RARA gene on chromosome 17, creating the PML-RARA fusion protein. This fusion protein acts as a dominant-negative inhibitor of retinoic acid signaling, causing a maturation arrest at the promyelocyte stage. Abnormal promyelocytes accumulate in the bone marrow and blood, express high levels of tissue factor, and predispose to severe coagulopathy and DIC. Treatment with ATRA or ATO overcomes this block by inducing terminal differentiation of promyelocytes. APL is a hematologic emergency.

KEY CYTOGENETIC DISTINCTIONS

CLINICAL PRESENTATION

Classic triad: fatigue/anemia, mucosal bleeding/petechiae, and DIC. APL commonly affects younger adults and may present with pancytopenia or elevated WBC. The peripheral smear shows hypergranular promyelocytes with abundant Auer rods, often described as "faggot cells," which confirm myeloid origin. DIC is the primary cause of early mortality, most commonly from intracranial and pulmonary hemorrhage.

DIAGNOSIS

The gold standard is RT-PCR for the PML-RARA fusion gene. FISH is also acceptable for confirmation. Peripheral smear and bone marrow biopsy support the diagnosis but cannot confirm the molecular subtype alone. IgH gene rearrangement is a lymphoid marker and is not used in APL or AML.

CRITICAL RULE: Start ATRA immediately upon clinical suspicion — do NOT wait for molecular confirmation.

RISK STRATIFICATION

Risk is based on WBC and platelet count at baseline, before any therapy.

High WBC is the strongest predictor of relapse risk. Ethnicity is NOT a standard prognostic factor. Platelet count only distinguishes low from intermediate risk.

TREATMENT

Mechanism of key agents: ATRA (tretinoin) induces terminal differentiation of leukemic promyelocytes and corrects underlying coagulopathy. ATO (arsenic trioxide) promotes degradation of the PML-RARA fusion protein and induces apoptosis. Anthracycline (idarubicin or daunorubicin) is a cytotoxic agent added in high-risk disease.

Treatment by risk group:

Important rules: Standard 7+3 chemotherapy is NOT appropriate for APL. ATRA and ATO are equally effective for induction — neither is superior alone. Cure rates exceed 90% with ATRA + ATO, with 5-year OS up to 88%. APL is one of the most curable leukemias.

MANAGEMENT OF DIC AND COAGULOPATHY

Start ATRA immediately — it corrects coagulopathy by differentiating promyelocytes. Keep platelets above 30 x 10⁹/L and fibrinogen above 100 mg/dL using cryoprecipitate, FFP, and platelets. Monitor PT/INR, aPTT, fibrinogen, and D-dimer frequently. Avoid invasive procedures when possible. The most common fatal complications are intracranial and pulmonary hemorrhage. Dexamethasone is NOT used for coagulopathy — it is reserved for differentiation syndrome only.

DIFFERENTIATION SYNDROME (DS)

• Differentiation syndrome is caused by ATRA and/or ATO and occurs in approximately 25–30% of APL patients. Onset is typically 7–14 days after initiation (median ~9–10 days; range 2–21 days). The mechanism is a cytokine storm released as promyelocytes differentiate and infiltrate organ systems.
• Risk factors for DS: WBC > 20 x 10⁹/L, BMI > 30 kg/m², and creatinine above normal. Age, sex, blast morphology, and concurrent chemotherapy are NOT risk factors.
• Clinical features (Frankel criteria — ≥3 required): fever, weight gain, pulmonary infiltrates, pleural or pericardial effusion, hypotension, hepatic failure, acute renal failure, and dyspnea/respiratory distress.
• Management: Start dexamethasone 10 mg IV every 12 hours at the earliest sign or symptom — this reduces DS mortality from ~30% to less than 5%. For mild-to-moderate DS, continue ATRA/ATO. For severe DS or significant hypoxia, temporarily hold ATRA for 48–72 hours, then reintroduce at 50% dose with stepwise increase. Oxygen and diuretics are supportive only. There is no evidence supporting routine prophylactic corticosteroids.

SINUSOIDAL OBSTRUCTION SYNDROME (SOS) vs. DIFFERENTIATION SYNDROME

SOS is associated with gemtuzumab ozogamicin use. It must be distinguished from DS.

Key rule: Reversal of portal flow + jaundice + painful hepatomegaly = SOS, not DS.

ATO (ARSENIC TRIOXIDE) — TOXICITIES AND MONITORING

Side effects include QT prolongation (risk of torsades de pointes, which can be fatal), hypokalemia, and hypomagnesemia. Monitoring requirements: keep K⁺ above 4.0 mEq/L, keep Mg²⁺ above 1.8 mg/dL, obtain baseline ECG and at least twice-weekly ECGs during induction. If QTc exceeds 500 msec, hold ATO, replete electrolytes, and discontinue other QT-prolonging medications. ATO is CONTRAINDICATED at any stage of pregnancy due to embryotoxicity.

ATRA (TRETINOIN) — SPECIAL TOXICITIES

Differentiation syndrome (see above). Pseudotumor cerebri occurs especially in children and presents with headache, vomiting, blurred vision, and papilledema. Management is to withhold ATRA and give acetazolamide ± mannitol; ATRA can be reintroduced after symptom improvement. Pediatric dose is 25 mg/m² (vs. standard 45 mg/m² in adults). ATRA is teratogenic in the first trimester and must be avoided.

APL IN PREGNANCY

RELAPSED APL AND MRD MONITORING

For late relapse (≥ 6 months): use ATO-based re-induction to achieve second complete remission (CR2), then consolidate with autologous HSCT (gold standard). If the patient remains MRD-positive after salvage, consider allogeneic HSCT instead. ATO remains effective even with prior exposure in late relapse. The first MRD check by RT-PCR should be performed after at least one cycle of consolidation — PCR positivity immediately after induction does NOT define induction failure. Induction failure is defined as failure to achieve CR after standard induction therapy.

FULL TREATMENT PROTOCOL SUMMARY — APL

HIGH-YIELD EXAM PEARLS — APL

• Diagnosis: t(15;17) is the APL diagnostic hallmark — confirm with RT-PCR for PML-RARA. "Faggot cells" on peripheral smear are promyelocytes with bundled Auer rods.
• Start ATRA immediately, before molecular confirmation.
• Treatment rules: Low/intermediate risk → ATRA + ATO (no chemo needed). High risk (WBC > 10) → ATRA + ATO + anthracycline or gemtuzumab. Never use standard 7+3 in APL. ATRA and ATO are equally effective. Cure rate exceeds 90%.
• Coagulopathy: DIC is the most common life-threatening early complication. Keep platelets above 30 and fibrinogen above 100 mg/dL.
• Dexamethasone is for DS only, not DIC.
• Differentiation syndrome: Caused by ATRA and/or ATO. Presents with fever, dyspnea, pulmonary infiltrates, weight gain, hypotension, and edema on days 7–14. Treat immediately with dexamethasone 10 mg IV every 12 hours. Hold ATRA only if severe hypoxia; restart at 50% dose.
• SOS (gemtuzumab): Painful hepatomegaly + jaundice + reversal of portal flow + low WBC. Chest X-ray is unremarkable (unlike DS).
• ATO toxicity: QTc > 500 msec → hold ATO and replete K⁺ and Mg²⁺. K⁺ goal above 4.0 mEq/L; Mg²⁺ goal above 1.8 mg/dL.
• ATO is contraindicated in all trimesters of pregnancy.
• Relapse: Late relapse (≥ 6 months) → ATO re-induction → CR2 → auto-HSCT. MRD-positive after salvage → consider allo-HSCT.
• Pregnancy: First trimester → daunorubicin only. Second/third trimester → ATRA + anthracycline. ATO is contraindicated at all stages.

ACUTE MYELOID LEUKEMIA (AML)

DEFINITION AND ETYMOLOGY

"Leukemia" derives from the Greek leukos (white) + haima (blood). AML is a clonal proliferation of myeloid blasts in bone marrow and/or peripheral blood with uncontrolled proliferation of immature blast cells and impaired differentiation. General diagnostic threshold: ≥ 20% blasts in bone marrow OR peripheral blood. Exception: AML is diagnosed regardless of blast count if t(8;21), inv(16)/t(16;16), or t(15;17) are present. del(7) does NOT bypass the 20% blast requirement — less than 20% blasts with del(7) = MDS, not AML.

EPIDEMIOLOGY AND ETIOLOGY

• AML primarily affects older adults (age ≥ 60 is a critical factor in treatment decisions). AML evolved from MDS if dysplasia is present in ≥ 50% of cells in ≥ 2 myeloid lineages. The most common inherited leukemia is CLL (familial risk 2–4x higher with family history), not AML. DIC can be a presenting feature, especially in APL.
• Therapy-related AML (t-AML) accounts for 10–20% of cases: alkylating agents or radiation → latency 5–7 years → del(5), del(7); topoisomerase II inhibitors → latency 1–3 years → 11q23 mutations. t-AML carries poorer prognosis vs. de novo AML within the same risk group.
• Key mutations and risk factors: FLT3-ITD, NPM1, CEBPA, IDH1/2, TP53; prior therapy with alkylating agents, topoisomerase II inhibitors, or radiation; MDS, Down syndrome, and benzene exposure.

DIAGNOSIS AND CLASSIFICATION

Diagnostics from most to least useful: bone marrow aspirate microscopy (essential for blast morphology ≥ 20% blasts), immunophenotyping (flow cytometry) using myeloid markers CD13, CD33, CD117, MPO, cytogenetics and molecular testing for t(8;21), inv(16), FLT3, NPM1, CEBPA, IDH1/2, TP53, and coagulation panel essential if APL/DIC is suspected. LEAST USEFUL: IgH (immunoglobulin heavy chain) gene rearrangement — this is a lymphoid (B-cell) marker entirely irrelevant to AML diagnosis.

FAB SUBTYPES — KEY PATHOGNOMONIC FEATURES

TRANSLOCATION DISTINCTION — HIGH YIELD

Core Binding Factor (CBF) AML = t(8;21) AND inv(16)/t(16;16) ONLY. t(15;17) and t(12;21) are NOT CBF-AML.

RISK STRATIFICATION (2022 ELN)

Key molecular marker rules:

• NPM1 mutation = good prognosis if ISOLATED; poor if combined with FLT3.
• CEBPA mutation = good prognosis (found in 6–15% of AML).
• FLT3 mutation = high WBC, poor prognosis; occurs in 30–40% of normal karyotype AML.

INDUCTION CHEMOTHERAPY

• Goal: reduce leukemic burden from 10¹² to less than 10⁹ (3-log reduction; morphologic CR).
• Standard "7+3" regimen: cytarabine 100–200 mg/m²/day continuous IV infusion × 7 days AND anthracycline × 3 days — NEVER REVERSED (cytarabine is always 7 days).
• For age < 60 fit patients: daunorubicin 90 mg/m² (ECOG 1900: CR 71% vs 54%; OS 24 vs 16 months).
• For age ≥ 60 or unfit: daunorubicin 45–60 mg/m². Acceptable alternative: idarubicin 12 mg/m²/day × 3 days. Increasing cytarabine dose beyond 100–200 mg/m² during induction does NOT improve CR or OS.
• NOT used in AML: doxorubicin, paclitaxel, docetaxel, etoposide (no added benefit), Hyper-CVAD (ALL regimen only). Refractory AML = failure to achieve CR after 2 induction courses.

INDUCTION REGIMEN BY PATIENT PROFILE

Key induction rules

• Azacitidine and decitabine as single agents are NOT FDA-approved for AML induction.
• LDAC has demonstrated superiority over best supportive care in elderly patients.
• Venetoclax must ALWAYS be used in combination — NEVER as single agent.
• Midostaurin = frontline only; NOT used as salvage therapy.
• CPX-351 delivers a fixed 5:1 molar ratio of cytarabine:daunorubicin and is indicated for secondary AML, t-AML, or MDS-related cytogenetics in patients 60–75. Adding etoposide to standard induction does NOT improve remission rates.

POST-REMISSION (CONSOLIDATION) THERAPY

• Goal: reduce leukemic burden from 10⁹ to zero (eradicate MRD; achieve cure). Without post-remission therapy, more than 90% of patients relapse within 1 year. Maintenance therapy is NOT effective in AML (unlike ALL).
• High-dose cytarabine (HiDAC) — gold standard:
  • age < 60, fit: 3,000 mg/m² IV Q12h on days 1, 3, 5 × 3–4 cycles.
  • Age > 60 or renal dysfunction: 1,000–1,500 mg/m² (attenuated to prevent cerebellar neurotoxicity).
  • HiDAC ALONE is superior to HiDAC + additional agents — etoposide, cyclophosphamide, amsacrine, and mitoxantrone showed NO added benefit. MOST PREFERRED AGENT to combine with HiDAC = NONE (HiDAC monotherapy is standard). Favorable-risk cytogenetics benefit most from HiDAC consolidation.
• Protocol continuity rule — consolidation MUST match induction:
  • induced with 7+3 + gemtuzumab (ALFA-0701) → consolidate with intermediate-dose cytarabine + daunorubicin + gemtuzumab.
  • Induced with CPX-351 → consolidate with CPX-351 (dauno 29 mg/m² + cytarabine 65 mg/m² on days 1 and 3).
  • Induced with azacitidine + ivosidenib → continue same combination.

ALLOGENEIC HSCT

Only potentially curative option for high-risk AML. Timing: CR1 (first complete remission) — do NOT delay for multiple HiDAC cycles.

• Favorable-risk AML (CBF, APL): allo-HCT in CR1 NOT required unless MRD+.
• Intermediate/adverse risk: allo-HCT in CR1 preferred. Allo-HCT is NOT indicated for ALL patients < 50 with an HLA-matched donor — risk/benefit must be individually assessed.
• Autologous HSCT: NOT used in AML. Radiation: NO role in AML treatment.

TARGETED AGENTS

RELAPSED/REFRACTORY AML — SALVAGE

KEY TOXICITIES

HiDAC: cerebellar neurotoxicity — dose-reduce if age > 60 or renal dysfunction; use steroid eye drops prophylactically. Anthracyclines: cardiotoxicity — monitor LVEF. IDH inhibitors: differentiation syndrome (treat with steroids); transaminitis; QT prolongation. Venetoclax + HMA: tumor lysis syndrome risk. Gemtuzumab: sinusoidal obstruction syndrome (SOS). Midostaurin/targeted agents: QT prolongation — ECG monitoring required.

SUPPORTIVE CARE

Antimicrobial prophylaxis during induction/consolidation:

• antifungal (fluconazole or posaconazole),
• antibacterial (levofloxacin),
• antiviral (acyclovir).
• TLS management: pre-hydration (2–3 L/day IV), allopurinol or rasburicase.
• G-CSF not routinely used during induction; may be used to support neutrophil recovery during consolidation.

HIGH-YIELD PEARLS — AML

• "7+3" = cytarabine 7 DAYS + anthracycline 3 DAYS — never reversed.
  • Daunorubicin 90 mg/m² superior to 45 mg/m² in patients < 60 (ECOG 1900).
• CBF-AML = t(8;21) + inv(16)/t(16;16) — both favorable, highly cytarabine-sensitive. t(15;17) = APL; t(12;21) = ALL — know the difference.
• HiDAC + additional chemo agents = NO benefit over HiDAC alone for consolidation. Most preferred agent to combine with HiDAC = NONE (HiDAC monotherapy is standard).
• APL: start ATRA BEFORE genetic confirmation if clinically suspected.
• Venetoclax = NEVER monotherapy; always in combination.
• Protocol continuity rule: consolidation regimen MUST match induction protocol. IgH rearrangement = LEAST useful in AML diagnosis (lymphoid marker).
• Maintenance therapy = NOT effective in AML.
• Azacitidine/decitabine as single agents = NOT FDA-approved for AML induction.
• Gemtuzumab: minimal/no benefit in adverse/complex karyotype AML; watch for SOS.
• HiDAC neurotoxicity: dose-reduce to 1,000–1,500 mg/m² if age > 60 or renal dysfunction.
• Enasidenib = IDH2; ivosidenib = IDH1 — do NOT mix them up.
• del(7) does NOT bypass the 20% blast rule — less than 20% blasts = MDS.
• AML evolved from MDS requires ≥ 50% dysplastic cells in ≥ 2 myeloid lineages.
• Most common inherited leukemia = CLL (not AML).
• Adding etoposide to standard induction does NOT improve remission rates.

ACUTE LYMPHOBLASTIC LEUKEMIA (ALL)

OVERVIEW AND DEFINITIONS

• ALL is a clonal overproduction of immature lymphocytes (lymphoblasts). B-cell ALL (B-ALL) accounts for ~75–85% of cases. T-cell ALL (T-ALL) accounts for ~15–25% of cases. Primary treatment goal = cure. Treatment duration is approximately 2–3 years.
• Four key treatment phases in order: Induction (4–6 weeks), CNS Prophylaxis, Consolidation (20–30 weeks), and Maintenance (2+ years). CNS is a sanctuary site — intrathecal (IT) chemotherapy is mandatory for ALL patients. Maintenance backbone: oral 6-mercaptopurine + weekly methotrexate.

RISK STRATIFICATION

INDUCTION REGIMEN SELECTION BY PATIENT PROFILE

Key rules: CALGB 10403 and CALGB 9511 are NOT for Ph+ ALL (TKI required). Dasatinib is the preferred TKI when CNS involvement is suspected — crosses the BBB. TKI must be added throughout ALL phases of Ph+ ALL treatment (induction, consolidation, maintenance). Mini-CVD + inotuzumab + ponatinib: insufficient safety data to support this combination.

INDUCTION — DRUG ROLES

Induction backbone: prednisone/prednisolone + vincristine + daunorubicin + asparaginase. CR backbone = vincristine + corticosteroid + anthracycline. ASPARAGINASE DOES NOT AFFECT CR RATE — it improves leukemia-free survival (LFS) only. Prednisolone response on day 8 is used for risk stratification.

TARGETED AND IMMUNOTHERAPY AGENTS

TOXICITY MANAGEMENT

CYTOKINE RELEASE SYNDROME (CRS) — Blinatumomab / CAR-T

Symptoms include fever, rigors, emesis, hypotension, elevated LFTs. High disease burden = major risk factor for CRS.

ICANS (Immune Effector Cell-Associated Neurotoxicity Syndrome)

ICE score used to assess severity.

KEY DISTINCTION: Tocilizumab treats CRS. Steroids (dexamethasone) treat ICANS.

TUMOR LYSIS SYNDROME (TLS)

Risk factors: high WBC, elevated LDH, hyperleukocytosis. Labs: hyperkalemia, hyperphosphatemia, hyperuricemia, rising creatinine. Step 1 (most important): Aggressive IV hydration (normal saline) — 150–300 mL/hr. Step 2: Allopurinol. Step 3: Rasburicase or sodium polystyrene sulfonate (only after IVF maximized). Last resort: Renal dialysis (when medical management fails).

ASPARAGINASE TOXICITIES:

Pancreatitis and thrombosis.

HSCT IN ALL

Allo-HSCT indications: Ph+, high-risk genetics, relapsed/refractory disease. T-ALL: allo-HSCT more commonly used in CR1 due to higher relapse risk. Autologous HSCT: NOT standard in ALL. MRD negativity is the key goal before transplant.

HIGH-YIELD PEARLS — ALL

• Ph+ ALL requires TKI throughout ALL phases — never omit.
• Dasatinib preferred TKI when CNS symptoms present — crosses the BBB.
• Asparaginase does NOT improve CR rate — improves LFS only.
• Blinatumomab for MRD+ requires ≥ 3 prior intensive chemo blocks (BLAST trial).
• Nelarabine = T-ALL ONLY; inotuzumab = R/R B-ALL ONLY.
• Grade 1 CRS → supportive care; Grade 2+ CRS → tocilizumab; Grade ≥ 2 ICANS → dexamethasone. Levetiracetam on day of CAR-T infusion — mandatory seizure prophylaxis; NO prophylactic steroids.

• TLS: first step = aggressive IV hydration (normal saline). MRD = strongest overall prognostic factor in ALL. ECOG1910 = NCCN preferred for Ph− B-ALL adults aged 30–70.

PRACTICE QUESTIONS WITH ANSWERS AND EXPLANATIONS — MDS

What is Myelodysplastic Syndrome (MDS)?

[expand] Answer: MDS is a group of clonal bone marrow disorders characterized by ineffective hematopoiesis, dysplasia in one or more myeloid cell lines, peripheral cytopenias, and potential progression to acute myeloid leukemia (AML) in approximately 20–30% of cases. [/expand]

What causes MDS?

[expand] Answer: MDS may arise de novo or secondary to prior chemotherapy, radiation, or environmental toxin exposure (e.g., benzene). It can also be linked to inherited bone marrow failure syndromes such as Fanconi anemia and Diamond-Blackfan anemia. [/expand]

Who is at risk for developing MDS?

[expand] Answer: Primarily older adults (> 60 years), patients previously treated with chemotherapy or radiation, and those with certain genetic predispositions or chronic exposure to toxins such as benzene. [/expand]

What are the common symptoms of MDS?

[expand] Answer: Symptoms are often due to low blood counts and include fatigue (anemia), infections (neutropenia), and bleeding or bruising (thrombocytopenia). Some patients are asymptomatic at diagnosis. [/expand]

How is MDS diagnosed?

[expand] Answer: Diagnosis requires CBC with differential, bone marrow biopsy (to assess dysplasia and blast count), and cytogenetic and molecular studies (to identify chromosomal or gene mutations). Risk stratification uses the IPSS-R system. [/expand]

What cytogenetic abnormalities are common in MDS?

[expand] Answer: Common abnormalities include del(5q), del(7q), monosomy 7, trisomy 8, and complex karyotypes. These findings help in risk stratification and treatment decisions. [/expand]

Can MDS progress to leukemia?

[expand] Answer: Yes. Around 20–30% of patients with MDS will progress to acute myeloid leukemia (AML), especially those with high-risk features. [/expand]

Is MDS a type of cancer?

[expand] Answer: Yes. MDS is considered a form of blood cancer originating from the bone marrow, though it behaves differently from acute leukemias. [/expand]

What is the difference between low-risk and high-risk MDS?

[expand] Answer: Low-risk MDS: fewer cytopenias, lower blast count (< 5%), favorable cytogenetics, median survival > 5 years. High-risk MDS: multiple cytopenias, higher blasts (5–19%), poor-risk cytogenetics (e.g., complex karyotype), median survival ~1–2 years. [/expand]

What are the treatment options for low-risk MDS?

[expand] Answer: Supportive care including transfusions and ESAs (epoetin alfa or darbepoetin alfa), lenalidomide (especially in del(5q) MDS), and immunosuppressive therapy (ATG + cyclosporine) in selected patients with hypoplastic MDS. [/expand]

What are the treatment options for high-risk MDS?

[expand] Answer: Hypomethylating agents (azacitidine or decitabine) as first-line therapy, allogeneic stem cell transplant (HSCT) as the only potential cure, and clinical trials for targeted therapies and novel agents. [/expand]

What are hypomethylating agents and how do they work?

[expand] Answer: Azacitidine and decitabine are DNA methyltransferase inhibitors that reverse abnormal gene silencing, improving cell differentiation and survival. Azacitidine (preferred) is given SubQ or IV for 7 days every 28 days and improves overall survival in high-risk MDS (AZA-001 trial). Decitabine is given IV over 5 days and is an alternative when azacitidine is not tolerated. A minimum of 4–6 cycles must be completed before declaring treatment failure. [/expand]

Is lenalidomide used in all types of MDS?

[expand] Answer: No. Lenalidomide is most effective in patients with isolated del(5q) and low-risk MDS. In a Phase II study, 83% of del(5q) patients responded versus 57% with normal karyotype. It is less effective or potentially harmful in patients without this cytogenetic abnormality. [/expand]

What role does HSCT play in MDS?

[expand] Answer: Allogeneic HSCT is the only potentially curative treatment for MDS. It is generally reserved for younger or fit older patients with high-risk disease due to associated morbidity and mortality. Eligibility requires ECOG PS ≤ 2, IPSS-R intermediate-2 or high-risk, available donor, and minimal comorbidities assessed by the HCT-CI index. Autologous HSCT is contraindicated in MDS. [/expand]

How is anemia managed in MDS?

[expand] Answer: Management includes RBC transfusions, ESAs (epoetin alfa or darbepoetin alfa) when EPO < 500 mU/mL and transfusion burden is low, lenalidomide for del(5q), and iron chelation therapy in patients with iron overload (ferritin > 1000 ng/mL after ≥ 20–25 RBC units with expected survival > 1 year). [/expand]

Can MDS patients develop iron overload?

[expand] Answer: Yes. Chronic RBC transfusions can cause secondary iron overload, increasing the risk of organ damage. Iron chelation therapy with deferasirox (oral) or deferoxamine (IV/SubQ) may be indicated. Exogenous iron supplements and ascorbic acid must also be discontinued as ascorbic acid increases iron absorption. [/expand]

What is the prognosis for MDS patients?

[expand] Answer: Prognosis depends on IPSS-R risk group. Low-risk: median survival > 5 years. High-risk: median survival ~1–2 years (as low as 4–8 months in IPSS-defined high-risk) with a higher chance of AML transformation. [/expand]

Are there targeted therapies for MDS?

[expand] Answer: Yes. Key targeted agents include lenalidomide (del(5q)), luspatercept (SF3B1/ring sideroblasts after ESA failure), ivosidenib (FDA-approved for R/R IDH1-mutated MDS), enasidenib (investigational for IDH2-mutated MDS), and APR-246 + azacitidine (investigational for TP53-mutated MDS). Hypomethylating agents (azacitidine, decitabine) target epigenetic modifiers by inhibiting DNA methyltransferase. [/expand]

Can MDS be cured?

[expand] Answer: The only potentially curative treatment is allogeneic HSCT. Otherwise, most therapies are palliative or disease-modifying, aiming to improve quality of life and delay progression. [/expand]

What are the key side effects of azacitidine and how are they managed?

[expand] Answer: Myelosuppression (common): Monitor CBC weekly during early cycles; may require dose delays or growth factor support. GI effects: nausea, vomiting, constipation — prophylactic antiemetics (e.g., ondansetron) recommended. Injection site reactions: rotate sites, use topical corticosteroids if needed. [/expand]

What mutations are targetable in MDS and how are they treated?

[expand] Answer: SF3B1 is associated with ring sideroblasts and patients may benefit from luspatercept. IDH1/IDH2 mutations can be targeted with ivosidenib (IDH1) or enasidenib (IDH2) in refractory MDS. TP53 mutations carry poor prognosis and are under investigation with APR-246 (eprenetapopt) in combination with azacitidine. [/expand]

What is luspatercept and when is it used in MDS?

[expand] Answer: Luspatercept is a TGF-β superfamily ligand trap that promotes late-stage erythroid maturation. It is approved for lower-risk MDS with ring sideroblasts and transfusion-dependent anemia in patients who have failed ESA therapy. [/expand]

When is immunosuppressive therapy appropriate in MDS?

[expand] Answer: In younger patients (< 60 years) with hypocellular MDS, HLA-DR15 positive status, or patients with PNH clones. Treatment is anti-thymocyte globulin (ATG) + cyclosporine with a response rate of ~30–40%. [/expand]

What clinical factors determine eligibility for allogeneic stem cell transplant in MDS?

[expand] Answer: Age and performance status (ECOG ≤ 2), IPSS-R risk group (generally intermediate-2 or high-risk), donor availability, and minimal comorbidities assessed using the HCT-CI index. [/expand]

When should iron chelation therapy be initiated in MDS patients?

[expand] Answer: Start iron chelation in low-risk MDS patients with expected survival > 1 year when transfusion burden reaches ≥ 20–25 RBC units and serum ferritin exceeds 1000 ng/mL. Agents: deferasirox (oral) or deferoxamine (IV/SubQ). Exogenous iron supplements and ascorbic acid must be discontinued. [/expand]

How is treatment response assessed in MDS?

[expand] Answer: Response criteria are defined by the International Working Group (IWG) across four dimensions: hematologic improvement (HI) meaning improved hemoglobin, platelets, or ANC; complete remission (CR) meaning normal counts, less than 5% marrow blasts, no dysplasia; partial remission (PR) meaning at least 50% reduction in blast percentage; and cytogenetic response, alteration of disease progression, and quality of life. [/expand]

What are treatment options for HMA-refractory high-risk MDS?

[expand] Answer: Clinical trials (first-line recommendation), venetoclax-based regimens (e.g., venetoclax + azacitidine), targeted agents (IDH1/2 inhibitors if mutations present), and palliative care/transfusions/supportive management. [/expand]

How do you monitor and manage cytopenias during HMA therapy?

[expand] Answer: Obtain baseline and serial CBC every 1–2 weeks during early cycles. Hold or delay therapy if ANC < 0.5 x 10⁹/L or platelets < 25 x 10⁹/L. Growth factors (e.g., G-CSF) may be used selectively in neutropenic fever. [/expand]

How many cycles of HMA therapy are needed before assessing response?

[expand] Answer: A minimum of 4–6 cycles is recommended before declaring treatment failure, as responses may be delayed. Continue in the absence of progression or unacceptable toxicity. [/expand]

What is the difference between MDS and aplastic anemia?

[expand] Answer: MDS is a clonal disorder with dysplasia and risk of AML transformation. Aplastic anemia is an immune-mediated marrow failure with hypocellularity but no dysplasia or clonal evolution (unless overlapping with PNH or evolves to MDS). MDS is treated per risk stratification while aplastic anemia is treated with IST: ATG + cyclosporine. [/expand]

What is the significance of TP53 mutations in MDS?

[expand] Answer: TP53 mutations are associated with complex karyotypes, poor prognosis, and resistance to conventional therapy. Patients may benefit from clinical trials such as APR-246 + azacitidine. [/expand]

What is the role of ESAs in MDS?

[expand] Answer: ESAs are used in low-risk MDS with symptomatic anemia. Best response occurs when serum EPO is < 500 mU/mL and transfusion burden is low. Agents include epoetin alfa and darbepoetin alfa. [/expand]

CJ is a 69-year-old female with low-risk MDS (4% blasts, normal cytogenetics, no del(5q)), epoetin level 157 units/L. She is symptomatic with fatigue and sore throat. Which agent is most appropriate?

A. Erythropoietin
B. Filgrastim
C. Eltrombopag
D. Lenalidomide

[expand] Answer: A. Erythropoietin

Explanation: The patient has low-risk MDS with normal cytogenetics and no del(5q), so lenalidomide is not indicated. Her EPO level of 157 units/L (< 500) suggests she will respond to an ESA, making erythropoietin with or without G-CSF appropriate first-line treatment. Filgrastim alone is not clearly indicated in MDS. Eltrombopag has no established role in MDS.

[/expand]

CJ is a 69-year-old female with low-risk MDS, ring sideroblasts, SF3B1 mutation, epoetin level 640 units/L, and requires 2 units RBCs every other week. Which agent is most appropriate?

A. Erythropoietin
B. Luspatercept
C. Eltrombopag
D. Lenalidomide

[expand] Answer: B. Luspatercept

Explanation: Luspatercept is indicated for low-risk MDS with ring sideroblasts in patients who have failed or are unlikely to respond to ESAs. The EPO level of 640 units/L (> 500) indicates she is unlikely to respond to an ESA, making erythropoietin incorrect. Eltrombopag has no role in MDS. Lenalidomide is not appropriate as she does not have del(5q).

[/expand]

CJ is a 69-year-old female with low-risk MDS, ring sideroblasts, SF3B1 mutation, epoetin level 150 units/L, and requires 2 units RBCs every other week. Which agent is most appropriate?

A. Decitabine
B. Lenalidomide
C. Epoetin
D. Luspatercept

[expand] Answer: C. Epoetin

Explanation: The EPO level of 150 units/L (< 500) indicates she is likely to respond to an ESA, making epoetin the correct first-line therapy. Decitabine should not be used in low-risk MDS unless other agents have failed. Lenalidomide is not appropriate without del(5q). Luspatercept is indicated only after ESA failure or when EPO > 500 makes ESA response unlikely.

[/expand]

CJ is a 69-year-old female with low-risk MDS, ring sideroblasts, SF3B1 mutation, epoetin level 150 units/L. Which agent is most appropriate?

A. Decitabine
B. Lenalidomide
C. Epoetin
D. ATGAM + cyclosporine

[expand]Answer: C. Epoetin

Explanation: EPO level < 500 units/L means she is likely to respond to an ESA, making epoetin the correct first-line choice. Decitabine is not appropriate in low-risk MDS as a first-line agent. Lenalidomide requires del(5q) which is absent here. ATGAM + cyclosporine should only be considered in hypoplastic MDS, not in this patient with ring sideroblasts and SF3B1 mutation.

[/expand]

Lenalidomide is most appropriate in an MDS patient with which cytogenetic feature?

A. Del(12p)
B. Del(5q)
C. FLT3-ITD
D. Normal cytogenetics

[expand] Answer: B. Del(5q)

Explanation: In a Phase II study, patients with del(5q) benefited most from lenalidomide — 83% of patients with del(5q) had a response vs. 57% with normal karyotype vs. 12% with other cytogenetic abnormalities. FLT3-ITD mutations respond to FLT3 inhibitors approved for AML, not lenalidomide.

[/expand]

TK is a 72-year-old male with low-grade MDS who has received more than 30 blood transfusions and takes daily iron supplementation. He presents with shortness of breath and abdominal pain. Ferritin is 3100 ng/mL. What is the most likely cause of his symptoms?

A. Untreated iron overload
B. Invasive pulmonary aspergillosis
C. Sinusoidal obstructive syndrome
D. Adverse drug reaction to iron supplements

[expand] Answer: A. Untreated iron overload

Explanation: TK's symptoms of shortness of breath and abdominal pain in the setting of > 30 transfusions and ferritin of 3100 ng/mL are consistent with iron overload. He should be started on iron chelation therapy (deferoxamine or deferasirox) and exogenous iron supplements and ascorbic acid must be discontinued. Aspergillosis is unlikely given preserved neutrophil count and no supporting diagnostic data. SOS requires evidence of weight gain, hyperbilirubinemia, and hepatomegaly, which are not described. Oral iron supplements alone do not cause systemic iron overload.

[/expand]

Pathophysiology of MDS involves:

a. Maturation arrest
b. Ineffective hematopoiesis
c. Increased apoptosis
d. Immunological abnormalities
e. All of the above

[expand] Answer: e. All of the above

Explanation: MDS is characterized by ineffective hematopoiesis (failure to produce enough functional blood cells), increased apoptosis driven by over-activation of TGF-β pathways causing premature cell death, maturation arrest preventing cells from developing into functional neutrophils or RBCs, and immunological abnormalities confirmed by the clinical success of immunosuppressive therapies like ATG and cyclosporine in ~30% of patients.

[/expand]

The median survival for high-risk MDS is:

a. 4–8 months
b. 1–2 years
c. 2–4 years
d. 4–6 years

[expand] Answer: b. 1–2 years

Explanation: Clinical trials for higher-risk MDS patients show median overall survival typically falls within the 1-to-2-year range, with some cooperative group trials showing median survival as low as 11 to 18 months. This underscores why higher-risk MDS is managed aggressively, with allogeneic HCT as the only curative goal for eligible patients. Note: the IPSS-defined high-risk group may have survival as low as 4–8 months, but the broader high-risk category median is ~1–2 years.

[/expand]

Response to MDS treatment is assessed by:

a. Hematological improvement
b. Cytogenetic improvement
c. Alteration of disease progression
d. Quality of life
e. All of the above

[expand] Answer: e. All of the above

Explanation: The International Working Group criteria define four specific aspects of response: hematological improvement (scored for each lineage), cytogenetic improvement (partial or complete response), alteration of disease progression (various measures of disease progression and survival), and quality of life.

[/expand]

Treatment for low-risk MDS includes all EXCEPT:

a. Erythropoietin
b. G-CSF
c. Lenalidomide
d. Reduced intensity allo-SCT

[expand] Answer: d. Reduced intensity allo-SCT

Explanation: Treatment for lower-risk MDS focuses on managing symptomatic cytopenias using ESAs, G-CSF (to augment ESA response), and lenalidomide (for del(5q)). Allogeneic HSCT, while the only curative treatment, is generally reserved for patients with higher-risk disease who have a high probability of progressing to AML and is not indicated for low-risk MDS.

[/expand]

JN is a 59-year-old female with high-risk MDS (IPSS score 25) with four siblings. She has required weekly RBC transfusions. Which is the best course of therapy?

A. Radiation to the hip
B. Autologous HSCT
C. Chemotherapy
D. Allogeneic HSCT

[expand] Answer: D. Allogeneic HSCT

Explanation: Allogeneic HSCT is indicated for patients with high-risk MDS as it provides the highest overall survival benefit compared to chemotherapy. Radiation has no role in MDS treatment and may worsen the disease. Autologous HSCT is contraindicated because the diseased marrow produces inadequate stem cells to collect. Chemotherapy can be considered in low-risk MDS or in high-risk patients ineligible for transplant.

[/expand]

According to NCCN guidelines, which patient is receiving the most appropriate therapy?

A. A 73-year-old male with lower-risk MDS with del(5q) and anemia receiving azacitidine
B. A 67-year-old female with higher-risk MDS with 12% blasts receiving luspatercept
C. A 58-year-old male with newly diagnosed hypoplastic MDS receiving epoetin
D. A 61-year-old female with newly diagnosed higher-risk MDS undergoing allogeneic cell transplantation

[expand] Answer: D. A 61-year-old female with newly diagnosed higher-risk MDS undergoing allogeneic cell transplantation

Explanation: The standard of care for higher-risk MDS in a young/fit/eligible patient is allo-HCT. Option A is incorrect because del(5q) patients should receive lenalidomide, not azacitidine (azacitidine is reserved for higher-risk MDS). Option B is incorrect because higher-risk MDS should receive an HMA or proceed to allo-transplant, not luspatercept. Option C is incorrect because hypoplastic MDS should be treated similarly to aplastic anemia with immunosuppressive therapy (IST), not epoetin.

[/expand]

PRACTICE QUESTIONS WITH ANSWERS AND EXPLANATIONS — APL

Which cytogenetic abnormality is characteristic of APL?

A. t(9;22)(q34;q11)
B. t(15;17)(q24;q21)
C. t(8;14)(q24;q32)
D. inv(16)(p13q22)

[expand] Answer: B. t(15;17)(q24;q21)

Explanation: The translocation t(15;17) is the defining diagnostic hallmark of APL. It fuses the PML gene on chromosome 15 with the RAR-α gene on chromosome 17, creating the PML-RARA fusion protein that prevents myeloid precursors from maturing into neutrophils. t(9;22) is the Philadelphia chromosome associated with CML and a subset of ALL. t(8;14) is associated with Burkitt lymphoma. inv(16) is associated with CBF-AML, a favorable-risk subtype distinct from APL.

[/expand]

True or False: The PML-RARA fusion protein promotes differentiation of myeloid precursors.

[expand] Answer: False

Explanation: The PML-RARA fusion protein in APL actually PREVENTS differentiation of myeloid precursors into mature neutrophils. It acts as a dominant-negative inhibitor of retinoic acid signaling, causing a maturation arrest at the promyelocyte stage. It is the treatment with ATRA or ATO that overcomes this block by inducing terminal differentiation.

[/expand]

What is the functional consequence of the PML-RARA fusion protein in APL?

[expand] Answer: It acts as a dominant-negative inhibitor of retinoic acid signaling, blocking differentiation of myeloid precursors at the promyelocyte stage, causing accumulation of abnormal promyelocytes in the bone marrow and blood. [/expand]

A 25-year-old woman presents with fatigue, mucosal bleeding, and easy bruising. Labs reveal pancytopenia and DIC. Which hematologic malignancy should be suspected?

A. Acute lymphoblastic leukemia (ALL)
B. Chronic myeloid leukemia (CML)
C. Acute promyelocytic leukemia (APL)
D. Hairy cell leukemia

[expand] Answer: C. Acute promyelocytic leukemia (APL)

Explanation: APL is highly associated with life-threatening DIC at diagnosis, manifesting as mucosal bleeding, easy bruising, and hypofibrinogenemia. DIC is the primary cause of early mortality in newly diagnosed APL. ATRA should be started immediately upon suspicion. ALL can present with pancytopenia but is not characteristically associated with early-onset DIC. CML typically presents with very high WBC and splenomegaly rather than pancytopenia and DIC. Hairy cell leukemia presents with splenomegaly and pancytopenia but does not cause acute coagulopathy.

[/expand]

True or False: DIC is a common and potentially fatal complication of APL.

[expand] Answer: True

Explanation: APL is strongly associated with coagulopathy and bleeding due to tissue factor released from abnormal promyelocytes. DIC is the primary cause of early mortality in APL, most commonly manifesting as intracranial and pulmonary hemorrhage.

[/expand]

Name two common symptoms or signs that may alert a clinician to suspect APL.

[expand] Answer: Bleeding (e.g., petechiae, mucosal bleeding) and fatigue or anemia symptoms (e.g., pallor, weakness). Note: DIC may also manifest as thrombotic complications. [/expand]

Which test is used to confirm the diagnosis of APL?

A. Peripheral blood smear alone
B. Bone marrow biopsy only
C. RT-PCR for PML-RARA fusion
D. Serum vitamin A level

[expand] Answer: C. RT-PCR for PML-RARA fusion

Explanation: RT-PCR is the gold standard molecular confirmatory test for APL, detecting the PML-RARA fusion gene created by t(15;17). It is also used to monitor response to therapy and detect MRD. Peripheral smear and bone marrow biopsy are essential initial steps but cannot confirm the molecular subtype alone. Serum vitamin A levels are not used in diagnosis despite the use of retinoic acid in treatment.

[/expand]

What characteristic finding might be seen on a peripheral smear in APL?

[expand] Answer: Promyelocytes with abundant Auer rods, often described as "faggot cells." Auer rods are needle-like, red-staining crystalline inclusion bodies within the cytoplasm of leukemia cells. Their presence confirms myeloid origin. In APL, Auer rods are often numerous or found in bundles. [/expand]

Which is the first-line treatment for APL upon diagnosis?

A. Imatinib
B. Methotrexate
C. All-trans retinoic acid (ATRA)
D. Cytarabine

[expand] Answer: C. All-trans retinoic acid (ATRA)

Explanation: ATRA induces differentiation of promyelocytes and corrects the underlying coagulopathy. It should be started immediately upon clinical suspicion, even before molecular confirmation, to prevent fatal hemorrhage from DIC.

[/expand]

True or False: Arsenic trioxide is used in the treatment of APL and has curative potential.

[expand] Answer: True

Explanation: Arsenic trioxide promotes degradation of the PML-RARA fusion protein and complements ATRA therapy. Combined ATRA + ATO therapy achieves cure rates exceeding 90%, making APL one of the most curable forms of leukemia.

[/expand]

Which best describes the mechanism of ATRA in treating APL?

A. Inhibits DNA synthesis
B. Stimulates apoptosis of promyelocytes
C. Induces differentiation of leukemic promyelocytes
D. Blocks tyrosine kinase activity

[expand] Answer: C. Induces differentiation of leukemic promyelocytes

Explanation: ATRA is a differentiating agent that forces the maturation and terminal differentiation of premature promyelocytes into mature neutrophils. This maturation ultimately leads to apoptosis, but the primary action is reversal of the maturation arrest caused by PML-RARA. By inducing differentiation, ATRA rapidly corrects the life-threatening DIC present at diagnosis.

[/expand]

Name the two agents commonly used together in the standard treatment of low- to intermediate-risk APL.

[expand] Answer: All-trans retinoic acid (ATRA) and arsenic trioxide (ATO). This chemotherapy-free combination is the standard of care for low/intermediate-risk APL and achieves cure rates exceeding 90%. [/expand]

True or False: With prompt and appropriate treatment, APL is one of the most curable forms of leukemia.

[expand] Answer: True

Explanation: Cure rates exceed 90% with ATRA + ATO therapy, with 5-year OS up to 88%. APL represents a paradigm of targeted therapy in oncology.

[/expand]

Which is a potential early complication of ATRA therapy?

A. Hyperuricemia
B. Differentiation syndrome
C. Tumor lysis syndrome
D. Hyperkalemia

[expand] Answer: B. Differentiation syndrome

Explanation: Differentiation syndrome is a hallmark complication of APL therapy with ATRA and/or ATO, occurring in approximately 25–30% of patients during induction. The median onset is 7–14 days after starting therapy. It is driven by a cytokine storm as immature promyelocytes begin to mature and differentiate. Hyperuricemia and hyperkalemia are features of tumor lysis syndrome, which is not the primary concern when initiating ATRA.

[/expand]

How is differentiation syndrome managed in APL patients receiving ATRA?

[expand] Answer: Management focuses on rapid detection and immediate initiation of corticosteroids. Primary therapy is dexamethasone 10 mg IV every 12 hours — this reduces DS mortality from ~30% to less than 5%. Continue ATRA for mild-to-moderate symptoms. Temporarily hold ATRA for 48–72 hours if cardiorespiratory symptoms become severe, then reintroduce at 50% dose with stepwise increase. Oxygen and diuretics are supportive only. For high-risk patients (WBC > 10 x 10⁹/L), prophylaxis with weight-based prednisone or fixed-dose dexamethasone is recommended. [/expand]

A 34-year-old man with newly diagnosed APL starts ATRA therapy. Two days later, he develops fever, respiratory distress, hypotension, and bilateral infiltrates on chest X-ray. What is the most likely diagnosis?

A. Sepsis
B. Tumor lysis syndrome
C. Differentiation syndrome
D. Pneumocystis pneumonia

[expand] Answer: C. Differentiation syndrome

Explanation: The patient exhibits hallmark symptoms of differentiation syndrome (DS): unexplained fever, respiratory distress, hypotension, and pulmonary infiltrates on chest X-ray within days of starting ATRA. DS is caused by a cytokine storm as immature promyelocytes begin to differentiate. Because these symptoms overlap with sepsis, clinicians often treat empirically for infection while simultaneously starting high-dose dexamethasone.

[/expand]

LJ is a 24-year-old male with t(15;17) on peripheral smear. WBC is 15 x 10⁹/L and platelet count is 10K. Which is the most appropriate treatment?

A. 7+3 with daunorubicin 90 mg/m²/dose
B. Midostaurin
C. Tretinoin, idarubicin, and arsenic trioxide
D. Arsenic trioxide alone

[expand] Answer: C. Tretinoin, idarubicin, and arsenic trioxide

Explanation: t(15;17) confirms APL diagnosis. WBC of 15 x 10⁹/L exceeds the high-risk threshold of > 10 x 10⁹/L, requiring addition of an anthracycline (idarubicin) to the ATRA + ATO backbone — this is the APML4 protocol. Standard 7+3 is not appropriate for APL. Midostaurin is used for FLT3-mutated AML. ATO alone without ATRA is not appropriate for any risk group.

[/expand]

On day 10 of LJ's treatment with tretinoin + arsenic + idarubicin, WBC is 21 x 10⁹/L. He exhibits fevers, hypotension, peripheral edema, and dyspnea. What does this describe?

A. Coagulopathy
B. Urosepsis
C. QTc prolongation
D. Differentiation syndrome

[expand] Answer: D. Differentiation syndrome

Explanation: LJ's presentation — fever, hypotension, peripheral edema, and dyspnea on day 10 — falls exactly within the median onset range of differentiation syndrome (DS) at 10–12 days. His WBC of 21 x 10⁹/L is a known risk factor. Coagulopathy manifests as hemorrhage or low fibrinogen, not fever and edema. Urosepsis overlaps with fever and hypotension, but dyspnea and edema in the setting of differentiating agents strongly points to DS. QTc prolongation manifests as cardiac arrhythmias, not the respiratory and fluid-overload symptoms seen here.

[/expand]

LJ received ATRA + ATO + gemtuzumab for high-risk APL. On day 15, WBC is 0.1 x 10⁹/L, bilirubin is 4.5 mg/dL. He exhibits fevers, 10% weight gain, painful hepatomegaly. Ultrasound reveals ascites and reversal of portal flow. Chest X-ray is unremarkable. What best describes LJ's symptoms?

A. Coagulopathy
B. Urosepsis
C. Sinusoidal obstruction syndrome
D. Differentiation syndrome

[expand] Answer: C. Sinusoidal obstruction syndrome

Explanation: LJ is experiencing sinusoidal obstruction syndrome (SOS), a well-documented side effect of gemtuzumab ozogamicin. The classic SOS presentation — reversal of portal flow on ultrasound, elevated bilirubin, painful hepatomegaly, weight gain from ascites, and very low WBC — matches perfectly. The unremarkable chest X-ray distinguishes it from DS, which typically shows pulmonary infiltrates. There are no signs of coagulopathy-related bleeding or thrombosis. Urosepsis cannot explain reversal of portal flow on ultrasound.

[/expand]

A 20-year-old woman presents with progressive fatigue and significant epistaxis. WBC is 120,000 cells/mL with 40% promyelocytes. PLT count is 15,000 cells/mL. While awaiting confirmation of the diagnosis, the initial treatment should be:

1. Steroids

2. ATRA

3. Fresh-frozen plasma

4. Arsenic trioxide

[expand] Answer: 2. ATRA (All-trans retinoic acid)

Explanation: ATRA should be started as soon as there is the slightest suspicion of APL, even before genetic or molecular confirmation. APL is frequently associated with life-threatening DIC, which is the major cause of early death. ATRA corrects the underlying coagulopathy by inducing maturation and terminal differentiation of promyelocytes. FFP and platelet transfusions are necessary supportive measures but are not primary therapy to reverse the disease process. With a WBC of 120,000 cells/mL, this patient is categorized as high-risk.

[/expand]

Three days after starting idarubicin and ATRA, the same patient develops shortness of breath and rapidly becomes hypoxic. Which is the best treatment for her hypoxia?

1. High-flow facemask oxygen

2. Lasix

3. Methylprednisolone

4. Albuterol

[expand] Answer: 3. Methylprednisolone

Explanation: The patient is experiencing differentiation syndrome (DS), presenting with rapid-onset shortness of breath and hypoxia after ATRA initiation. Steroids are the standard of care for DS. While dexamethasone 10 mg IV every 12 hours is the specific agent most cited, methylprednisolone is a glucocorticoid that also halts the underlying inflammatory cytokine storm. Oxygen is supportive only and does not treat the underlying pathology. Lasix helps with fluid overload but will not stop the cytokine-driven pulmonary infiltrates. Albuterol is for bronchospasm, not the interstitial infiltrates seen in DS. ATRA should also be temporarily held given severe cardiorespiratory symptoms.

[/expand]

Six months later, the same patient's CBC normalized and she has tolerated consolidation therapy. What is the most concerning factor for her relapse?

1. Her coagulopathy at diagnosis
2. The initial WBC count
3. Her ethnicity
4. None of the above

[expand] Answer: 2. The initial WBC count

Explanation: In APL, risk stratification is used to determine the risk of relapse. A patient is classified as high-risk when initial WBC is > 10 x 10⁹/L. This patient's WBC was 120,000 cells/mL at diagnosis, placing her firmly in the high-risk category with a historically higher probability of disease recurrence. Coagulopathy is a major cause of early mortality but is not the primary predictor of long-term relapse risk. Ethnicity is not a standard prognostic factor for APL relapse risk.

[/expand]

Three years later, the same patient presents with elevated WBC and peripheral blood PCR confirms t(15;17). Which treatment options may be considered?

1. Arsenic trioxide
2. Gemtuzumab ozogamicin
3. Autologous HSCT after achieving CR
4. Arsenic trioxide followed by transplantation

[expand] Answer: 4. Arsenic trioxide followed by transplantation

Explanation: This is a late relapse (3 years after initial diagnosis, well beyond the ≥ 6-month threshold). Standard protocols recommend ATO-based re-induction to achieve a second complete remission (CR2). Once MRD-negative by PCR, autologous HSCT is the gold standard for long-term survival. If the patient achieves clinical remission but remains MRD-positive, allogeneic HSCT would be considered instead. ATO remains effective even with prior exposure in late relapse.

[/expand]

The high-risk marker in APL is:

a. Promyelocyte count
b. Blast count
c. Total leukocyte count
d. Platelet count

[expand] Answer: c. Total leukocyte count

Explanation: In APL, a patient is classified as high-risk specifically when their WBC count exceeds 10 x 10⁹/L. While platelet count is used to distinguish between low-risk (platelets > 40 x 10⁹/L) and intermediate-risk (platelets ≤ 40 x 10⁹/L), the transition to high-risk is based solely on the total leukocyte count.

[/expand]

True regarding treatment of APL — all EXCEPT:

a. Best results are obtained by ATRA induction plus two cycles of consolidation chemotherapy followed by ATRA maintenance
b. Treatment-related APL has a prognosis similar to primary APL
c. Primary resistance is very uncommon
d. Induction failure is defined as PML-RARA positive after induction therapy

[expand] Answer: d. Induction failure is defined as PML-RARA positive after induction therapy — this statement is FALSE.

Explanation: The first MRD assessment by RT-PCR for PML-RARA should only occur after at least one cycle of consolidation therapy. Many patients remain molecularly positive immediately after induction; therefore, PCR positivity at that early stage does NOT define induction failure. Induction failure is defined as failure to achieve complete remission after standard induction therapy. Treatment-related APL does not differ prognostically from de novo APL (b is true). Primary resistance is rare as APL is highly sensitive to differentiating agents with CR rates often reaching 90%+ (c is true).

[/expand]

True regarding retinoic acid syndrome (differentiation syndrome):

a. Seen in 25% of APL patients
b. Occurs 2 to 21 days after initiation of treatment
c. More frequently in patients with a high WBC count at diagnosis
d. All of the above

[expand] Answer: d. All of the above

Explanation: Incidence is approximately 25–30% of APL patients. Timing ranges from day 2 to day 21 (median 10–12 days). High WBC count at diagnosis (> 10 x 10⁹/L or > 20 x 10⁹/L in some contexts) is a primary risk factor for developing DS.

[/expand]

Risk of relapse in APL is stratified by baseline:

a. Prothrombin time and platelet count
b. WBC and platelet count
c. Prothrombin time and fibrinogen
d. Hemoglobin and platelet count

[expand] Answer: b. WBC and platelet count

Explanation: Risk stratification for APL is based on WBC count and platelet count at diagnosis prior to any therapy. Low-risk: WBC ≤ 10 x 10⁹/L and platelets > 40 x 10⁹/L. Intermediate-risk: WBC ≤ 10 x 10⁹/L and platelets ≤ 40 x 10⁹/L. High-risk: WBC > 10 x 10⁹/L regardless of platelet count.

[/expand]

Treatment of coagulopathy in APL includes all EXCEPT:

a. Immediate start of ATRA therapy
b. Keeping platelet count above 30 x 10⁹/L
c. Maintaining fibrinogen concentration above 100 mg/dL
d. Starting dexamethasone 10 mg twice daily

[expand]Answer: d. Starting dexamethasone 10 mg twice daily

Explanation: Dexamethasone 10 mg every 12 hours is specifically indicated for differentiation syndrome, NOT for primary management of coagulopathy. ATRA initiation immediately upon suspicion (a) is foundational as it corrects coagulopathy by inducing cell maturation. Keeping platelets above 30 x 10⁹/L (b) and fibrinogen above 100 mg/dL (c) are standard supportive care components for APL coagulopathy management.

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True regarding induction treatment for APL:

a. Induction with arsenic trioxide is superior to ATRA plus anthracycline
b. Induction with ATRA plus anthracycline is superior to arsenic trioxide
c. Both are equally effective
d. Not evaluated

[expand]Answer: c. Both are equally effective

Explanation: Clinical data demonstrated that ATRA + ATO is non-inferior to the historical standard of ATRA + idarubicin (AIDA). Because outcomes are comparable, ATRA + ATO is now preferred for low-to-intermediate risk patients as a chemotherapy-free option that reduces the need for intensive cytotoxic support.

[/expand]

Risk factors for the development of differentiation syndrome are:

a. Age more than 60 years
b. Female sex
c. Morphological characteristics of blasts
d. Concomitant use of chemotherapy
e. None of the above

[expand]Answer: e. None of the above

Explanation: The documented risk factors for differentiation syndrome are high WBC count (> 10 x 10⁹/L or > 20 x 10⁹/L in some references) and high BMI (> 30 kg/m²), and creatinine above normal. Age, sex, blast morphology, and concurrent chemotherapy are NOT listed risk factors for DS development.

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True about differentiation syndrome:

a. Can develop with either ATRA or ATO
b. Incidence is up to 27% of APL cases
c. Begins at an interval of 7–14 days
d. Includes fever, weight gain, pulmonary infiltrate, pericardial or pleural effusion
e. All of the above

[expand] Answer: e. All of the above

Explanation: DS can develop with ATRA, ATO, or both. Incidence is approximately 25–30% (literature cites ranges that include 27%). Onset is typically 7–14 days after starting therapy (median 10–12 days). Clinical features include unexplained fever, rapid weight gain, hypotension, dyspnea with pulmonary infiltrates, and pleural or pericardial effusions from third-spacing of fluids. Treatment is immediate dexamethasone 10 mg IV every 12 hours.

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A seven-year-old child with APL developed headache, vomiting, and blurring of vision after 15 days of ATRA treatment. The most effective intervention would be:

a. Give platelets for suspected IC bleed
b. Give dexamethasone for ATRA syndrome
c. Do a lumbar puncture to rule out CNS leukemia
d. Withhold ATRA and give acetazolamide

[expand] Answer: d. Withhold ATRA and give acetazolamide

Explanation: Headache, vomiting, and blurring of vision in a child receiving ATRA are highly suggestive of pseudotumor cerebri (idiopathic intracranial hypertension), a known ATRA toxicity especially in children. Management is to withhold ATRA and give acetazolamide ± mannitol; ATRA can be reintroduced after symptom improvement. Differentiation syndrome
(b) presents with respiratory distress and edema, not isolated neurological symptoms. Intracranial bleed
(a) is more of a concern early in APL, and by day 15 coagulopathy is typically resolving. A lumbar puncture
(c) would be risky with any lingering concerns about intracranial pressure.

[/expand]

Side effects of arsenic trioxide include:

a. QT prolongation
b. Hypokalemia
c. Hypomagnesemia
d. All of the above

[expand] Answer: d. All of the above

Explanation: ATO is associated with QT prolongation (risk of torsades de pointes, which can be fatal), hypokalemia, and hypomagnesemia. Monitoring requires maintaining K⁺ above 4.0 mEq/L and Mg²⁺ above 1.8 mg/dL. ATO must be withheld when QTc exceeds 500 msec, electrolytes repleted, and other QT-prolonging medications discontinued.

[/expand]

Treatment of a pregnant female with APL in the first trimester is:

a. ATRA
b. Arsenic trioxide
c. Daunorubicin
d. Supportive care with platelets and FFP
e. None of the above

[expand] Answer: c. Daunorubicin

Explanation: ATRA is highly teratogenic and must be avoided in the first trimester unless termination of pregnancy is planned. ATO is embryotoxic and is strictly contraindicated at any stage of pregnancy. For first-trimester patients who do not wish to terminate, guidelines recommend induction with daunorubicin alone. Once the patient reaches the second or third trimester, ATRA may be introduced into the regimen.

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D1 is a 35-year-old female with WBC 30 x 10⁹/L and t(15;17) rearrangement. Which is the best treatment?

A. ATRA single agent
B. ATRA + idarubicin
C. ATRA + arsenic trioxide
D. 7+3 + idarubicin

[expand] Answer: B. ATRA + idarubicin

Explanation: t(15;17) confirms APL. With WBC > 10 x 10⁹/L, D1 is high-risk and requires the addition of an anthracycline such as idarubicin to the differentiating backbone. Low-intermediate risk patients (WBC ≤ 10 x 10⁹/L) may receive ATRA + ATO alone, which is non-inferior to ATRA + idarubicin. Standard 7+3 is never appropriate for APL.

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ZL is a 5-year-old male with WBC 15,000 cells/mm³ and confirmed APL diagnosis. Which is the appropriate induction regimen?

A. ATRA + idarubicin + arsenic trioxide
B. Cytarabine + idarubicin
C. ATRA + gemtuzumab
D. Cytarabine + methotrexate

[expand] Answer: A. ATRA + idarubicin + arsenic trioxide

Explanation: ZL is high-risk due to WBC > 10 x 10⁹/L. The preferred induction regimens for high-risk APL are ATRA + idarubicin + ATO (APML4 protocol) or ATRA + ATO + gemtuzumab. Since ZL has no cardiac issues, ATRA + idarubicin + ATO is best. If he had a prolonged QTc, ATRA + gemtuzumab would be appropriate instead. Cytarabine + idarubicin is standard for other AML subtypes, not APL. Cytarabine + methotrexate is used in ALL, not APL.

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A 52-year-old female with suspected leukemia has WBC 726 x 10⁹/L, Uric acid 12.9, Phosphorus 5.8, LDH 1503. Which drug is preferred for initial treatment?

A. Tretinoin
B. Imatinib
C. Prednisone
D. Hydroxyurea

[expand]Answer: D. Hydroxyurea

Explanation: This patient presents with extreme hyperleukocytosis (WBC 726 x 10⁹/L) and laboratory signs of tumor lysis syndrome (elevated uric acid, phosphorus, and LDH). Hydroxyurea must be started immediately to control leukocytosis while awaiting molecular and cytogenetic results. Specific agents like tretinoin (APL) or imatinib (CML) require genetic confirmation before use. Prednisone alone is not appropriate for cytoreduction of hyperleukocytosis.

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Fever, pulmonary infiltrates, acute respiratory distress, pulmonary capillary leakage, and weight gain are acute adverse effects associated with which agent?

A. Hydroxyurea
B. Busulfan
C. Nilotinib
D. Tretinoin (Vesanoid)

[expand] Answer: D. Tretinoin (Vesanoid)

Explanation: These symptoms — fever, dyspnea, weight gain, and pulmonary infiltrates — are hallmark signs of differentiation syndrome, a potentially fatal complication specifically associated with tretinoin (ATRA) and arsenic trioxide. The syndrome is driven by a cytokine storm as immature promyelocytes begin to mature and differentiate, causing them to migrate to and infiltrate various organ systems.

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PRACTICE QUESTIONS WITH ANSWERS AND EXPLANATIONS — AML

The word "leukemia" means:

a. French word for "blood infection"
b. Greek word for "white blood"
c. Latin word for "white cell"
d. Sanskrit word for "blood weakness"

[expand] Answer: b. Greek word for "white blood"

Explanation: Leukemia derives from the Greek "leukos" meaning "white" and "haima" meaning "blood."

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20% blasts are NOT required for AML diagnosis if the following cytogenetic abnormalities are present, EXCEPT:

A. t(8;21)
B. t(16;16)
C. del(7)
D. All of the above

[expand] Answer: C. del(7)

Explanation: t(8;21), inv(16), t(16;16), and t(15;17) allow AML diagnosis regardless of blast percentage. del(7) is a significant adverse-risk cytogenetic abnormality but does NOT bypass the 20% blast requirement. A patient with del(7) and less than 20% blasts is classified as MDS, not AML.

[/expand]

Poor prognosis in AML is seen with which molecular defect?

a. AML with mutated NPM1
b. AML with mutated CEBPA
c. AML with mutations in FLT3
d. None of the above

[expand] Answer: c. AML with mutations in FLT3

Explanation: FLT3 mutations occur in 30–40% of AML with normal cytogenetics and are associated with high WBC counts and poor prognosis. NPM1 mutations carry better prognosis when isolated but poor prognosis if combined with FLT3. CEBPA mutations (found in 6–15% of AML) are associated with good prognosis.

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AML with t(8;21)(q22;q22) has all EXCEPT:

a. Favorable prognosis
b. Blasts with long thin Auer rods
c. Highly sensitive to cytarabine
d. Patients with RUNX1-RUNX1T1 detected by RT-PCR in remission have a poor prognosis

[expand] Answer: d. Patients with RUNX1-RUNX1T1 detected by RT-PCR in remission have a poor prognosis — this is FALSE.

Explanation: RUNX1-RUNX1T1 detected by RT-PCR in remission does NOT indicate poor prognosis in t(8;21) AML. This is a key distinguishing fact. AML with t(8;21) has favorable prognosis (a), long thin Auer rods (b), and is highly sensitive to cytarabine (c) — all of these are true.

[/expand]

True regarding post-remission therapy in AML:

a. Is required only in intermediate and high-risk patients
b. Standard dose and high-dose cytarabine are equally effective
c. Maintenance therapy is not effective
d. All of the above

[expand] Answer: c. Maintenance therapy is not effective

Explanation: Without post-remission therapy, more than 90% of patients relapse within 1 year, so it is required in ALL risk groups (a is false). High-dose cytarabine (HiDAC) is superior to standard-dose cytarabine for consolidation because high intracellular concentrations overcome mechanisms of resistance (b is false). Maintenance therapy is NOT effective in AML, unlike in ALL (c is true and the single correct answer).

[/expand]

Remission induction chemotherapy aims to reduce the burden of leukemic cells from 10¹² to:

a. 10³
b. 10⁶
c. 10⁹
d. Zero

[expand] Answer: c. 10⁹

Explanation: Induction therapy aims to reduce the total body leukemia cell population from approximately 10¹² to below the cytologically detectable level of about 10⁹ cells — a three-log reduction. A substantial burden of leukemia cells persists undetected (minimal residual disease), leading to relapse if no further therapy is given. Post-induction consolidation therapy is designed to eradicate residual leukemia with the goal of reducing the burden to zero.

[/expand]

Consolidation chemotherapy aims to reduce the burden of leukemic cells to:

a. 10³
b. 10⁶
c. 10⁹
d. Zero

[expand] Answer: d. Zero

Explanation: Consolidation chemotherapy is designed to eradicate residual leukemia (MRD), allowing the possibility of cure. Induction reduces burden to < 10⁹ (morphologic remission). Consolidation targets residual disease with the goal of zero leukemic cells.

[/expand]

Most preferred agent to be used along with high-dose cytarabine (HiDAC) in consolidation for AML is:

a. Etoposide
b. Cyclophosphamide
c. Mitoxantrone
d. Daunorubicin
e. None of the above

[expand] Answer: e. None of the above

Explanation: HiDAC monotherapy is the standard consolidation for AML. Studies attempting to improve survival by combining HiDAC with etoposide, cyclophosphamide, amsacrine, or mitoxantrone have NOT shown superiority over HiDAC alone. HiDAC achieves high intracellular drug concentrations by saturating the deaminating enzyme pathway, effectively eliminating MRD without the need for additional cytotoxic agents.

[/expand]

Allogeneic transplant in high-risk AML is preferred in:

a. First complete remission
b. After completing 3 cycles of HiDAC consolidation
c. In second complete remission
d. Any of the above

[expand] Answer: a. First complete remission

Explanation: Allo-HSCT should be performed after achieving initial complete remission (CR1) in high-risk AML. Post-remission consolidation with multiple HiDAC cycles does not improve outcomes compared to proceeding directly to transplant after induction. Favorable-risk AML (CBF, APL) does NOT require allo-HCT in CR1 unless MRD-positive.

[/expand]

Which is LEAST valuable in the diagnosis of AML?

a. Microscopic analysis of the bone marrow aspirate
b. Immunophenotypic analysis of a bone marrow sample
c. Cytogenetic analysis of peripheral blood
d. Detection of clonal rearrangement of the immunoglobulin heavy chain gene

[expand] Answer: d. Detection of clonal rearrangement of the immunoglobulin heavy chain (IgH) gene

Explanation: IgH gene rearrangement is used to diagnose B-cell lymphoid malignancies (ALL, lymphoma) by identifying clonal B-cell populations. It is entirely irrelevant to AML, which is a myeloid malignancy. AML is confirmed through myeloid lineage-specific tests: bone marrow aspirate microscopy (essential for blast morphology ≥ 20% blasts), immunophenotyping to identify myeloid markers (CD13, CD33, MPO), and cytogenetics to detect prognostic chromosomal abnormalities.

[/expand]

Most common type of inherited leukemia is:

a. ALL
b. AML
c. CLL
d. CML

[expand] Answer: c. CLL

Explanation: CLL has a familial risk that is 2–4× higher with a family history, making it the most common inherited leukemia. Although AML is associated with inherited syndromes such as Down syndrome, CLL has the strongest familial/inherited risk.

[/expand]

Core binding factor AML includes:

a. AML with t(8;21)
b. AML with t(15;17)
c. AML with t(12;21)
d. All of the above

[expand] Answer: a. AML with t(8;21)

Explanation: Core Binding Factor (CBF) AML is specifically defined by t(8;21), inv(16), or t(16;16). t(15;17) is the hallmark of APL — although also favorable-risk, it is a distinct subtype with different treatment protocols and is NOT CBF-AML. t(12;21) (ETV6-RUNX1) is associated with ALL, not AML at all.

[/expand]

The best induction regimen for AML is daunorubicin with:

a. Cytarabine 100–200 mg/m² for 7 days
b. Cytarabine 400 mg/m² for 7 days
c. Cytarabine 3000 mg/m² for 3 days
d. Any of the above

[expand] Answer: a. Cytarabine 100–200 mg/m² for 7 days

Explanation: The standard "7+3" induction regimen uses cytarabine 100–200 mg/m²/day as a continuous IV infusion for 7 days combined with 3 days of an anthracycline. Increasing the cytarabine dose beyond 100–200 mg/m² during induction does NOT improve CR rates or overall survival. High-dose cytarabine (3,000 mg/m²) is reserved for consolidation, not induction.

[/expand]

True regarding AML induction — all EXCEPT:

a. Patients failing to achieve CR after two induction courses are considered refractory
b. The distribution of cytogenetic subtypes is related to age
c. Remission rates are lower if patients have an antecedent hematological disorder
d. Addition of etoposide increases remission rates

[expand] Answer: d. Addition of etoposide increases remission rates — this is FALSE.

Explanation: Comparative studies have not shown a benefit in remission rates or survival when adding etoposide or other cytotoxic agents to standard induction backbones. Refractory AML is correctly defined as failure to achieve CR after 2 induction courses (a is true). Older age increases the likelihood of unfavorable cytogenetic characteristics (b is true). Secondary AML from prior hematological disorders has significantly lower CR rates and OS (c is true).

[/expand]

Which statement about AML is FALSE?

A. It is most common in elderly
B. It can be caused by chemotherapy
C. More than 20% blast cells in the bone marrow are required for ALL cases of AML
D. Disseminated intravascular coagulation can be a presenting feature

[expand] Answer: C. More than 20% blast cells in the bone marrow are required for ALL cases of AML — this is FALSE.

Explanation: While WHO generally requires ≥ 20% blasts for AML diagnosis, exceptions exist: t(8;21), inv(16)/t(16;16), and t(15;17) allow AML diagnosis regardless of blast percentage. AML is most common in older adults (A is true). Prior alkylating agents and topoisomerase II inhibitors cause therapy-related AML (B is true). DIC is a classic presenting feature, especially in APL (D is true).

[/expand]

Which statement about AML is NOT true?

A. AML M4 and M5 have better prognosis than AML M6 and M7
B. It has a cure rate of > 80% in some subtypes
C. Allogeneic stem cell transplantation is needed in ALL patients less than 50 years old with an HLA-matched donor
D. Auer rods are seen in some but not all subtypes of AML

[expand] Answer: C. Allogeneic SCT is needed in ALL patients less than 50 years old with an HLA-matched donor — this is NOT true.

Explanation: Allo-HSCT is not recommended for all patients in first remission. Favorable-risk AML patients (CBF-AML, APL) do NOT require allo-HCT in CR1 unless persistently MRD-positive. Risk/benefit must be individually assessed. APL has 5-year OS up to 88% (B is true). FAB M6 and M7 historically have worse prognosis than M4 and M5 (A is true). Auer rods are present in some but not all AML subtypes (D is true).

[/expand]

MA is a 55-year-old male with newly diagnosed AML starting induction. Which is the standard regimen?

A. Cytarabine continuous infusion for 7 days and doxorubicin IV push for 3 days
B. Cytarabine continuous infusion for 7 days and paclitaxel IV for 3 days
C. Cytarabine continuous infusion for 7 days and daunorubicin IV push for 3 days
D. Cytarabine continuous infusion for 7 days and docetaxel IV for 3 days

[expand] Answer: C. Cytarabine continuous infusion for 7 days and daunorubicin IV push for 3 days

Explanation: The standard "7+3" regimen consists of cytarabine 100–200 mg/m²/day continuous IV infusion for 7 days plus daunorubicin (or idarubicin) IV for 3 days. Doxorubicin is used in ALL protocols or late intensification, not standard AML induction. Paclitaxel and docetaxel (taxanes) are not used in standard AML induction regimens.

[/expand]

BM is a 55-year-old female with AML showing normal cytogenetics and FLT3-ITD mutation. Which risk category does she fall into?

A. Better risk
B. Intermediate risk
C. Poor risk
D. Further information is needed

[expand] Answer: B. Intermediate risk

Explanation: According to the 2022 ELN Risk Stratification criteria, normal cytogenetics with FLT3-ITD mutation places the patient in the Intermediate Risk group, regardless of NPM1 mutation status or FLT3-ITD allelic ratio. This is a key 2022 ELN update — the allelic ratio no longer needs to be distinguished to determine risk in this setting.

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MA is a 75-year-old male with newly diagnosed AML. Which is the most appropriate standard FDA-approved treatment?

A. Cytarabine continuous infusion for 7 days and daunorubicin IV push for 3 days
B. Cytarabine 20 mg SQ BID × 10 days (LDAC)
C. Azacitidine
D. Decitabine

[expand] Answer: B. Cytarabine 20 mg SQ BID × 10 days (LDAC)

Explanation: For a 75-year-old patient, low-dose cytarabine (LDAC) is the most appropriate FDA-recognized low-intensity regimen. It has demonstrated superiority over best supportive care in older adults. Although azacitidine and decitabine are used in clinical practice, the FDA has not approved them as single agents for AML induction. Standard 7+3 intensive induction is generally reserved for fit patients and carries high morbidity in elderly patients.

[/expand]

RC is a 52-year-old female with de novo favorable-risk AML, CD33 negative, FLT3 negative. Which is the best remission induction therapy?

A. 7+3 with daunorubicin 45 mg/m²/day
B. 7+3 with daunorubicin 90 mg/m²/day
C. Hyper-CVAD
D. Liposomal cytarabine and daunorubicin

[expand] Answer: B. 7+3 with daunorubicin 90 mg/m²/day

Explanation: For a fit 52-year-old with de novo AML, the ECOG 1900 trial demonstrated that daunorubicin 90 mg/m² significantly improved CR rates (71% vs. 54%) and median OS (24 vs. 16 months) compared to 45 mg/m². Since RC is CD33 negative, gemtuzumab is not indicated; since she is FLT3 wild-type, midostaurin is not needed. Hyper-CVAD is an ALL regimen. CPX-351 (liposomal formulation) is for secondary AML or MDS-related changes in older adults, not for de novo favorable-risk AML in a younger patient.

[/expand]

Following induction with 7+3 (daunorubicin 90 mg/m²), RC achieved complete remission. Which is the most appropriate post-remission therapy?

A. Cytarabine 3,000 mg/m²/dose IV Q12h on days 1, 3, 5
B. Cytarabine 1,000 mg/m²/dose IV Q12h on days 1, 3, 5
C. 7+3 with daunorubicin 90 mg/m²
D. 5+2 with idarubicin 12 mg/m²

[expand] Answer: A. Cytarabine 3,000 mg/m²/dose IV Q12h on days 1, 3, 5

Explanation: For a 52-year-old patient with favorable-risk AML in CR, high-dose cytarabine (HiDAC) at 3,000 mg/m² Q12h on days 1, 3, and 5 is the gold standard consolidation. Patients under 60 receive the full dose; the attenuated dose of 1,000–1,500 mg/m² (B) is reserved for patients > 60 or those with renal dysfunction to minimize cerebellar neurotoxicity. 5+2 regimen (D) is for patients with residual blasts after induction (incomplete response), not for patients already in CR.

[/expand]

OT is a 45-year-old male with AML-M4. WBC 7,000 cells/mm³ and 48% blasts. Which is the best induction regimen?

A. Cytarabine 200 mg/m² × 3 days plus daunorubicin 60 mg/m² × 7 days
B. Cytarabine 200 mg/m² × 7 days plus daunorubicin 60 mg/m² × 3 days
C. Cytarabine 200 mg/m² × 7 days plus daunorubicin 90 mg/m² × 3 days
D. Cytarabine 200 mg/m² × 3 days plus daunorubicin 90 mg/m² × 7 days

[expand] Answer: C. Cytarabine 200 mg/m² × 7 days plus daunorubicin 90 mg/m² × 3 days

Explanation: For a fit 45-year-old, the standard "7+3" regimen with the higher daunorubicin dose of 90 mg/m² is appropriate based on the ECOG 1900 trial showing significantly improved CR rates and OS in patients under 60. The structure must always be cytarabine for 7 days and anthracycline for 3 days — never reversed. Options A and D invert the schedule incorrectly. Option B uses a suboptimal daunorubicin dose of 60 mg/m².

[/expand]

ML is a 49-year-old female with WBC 9,100, Hgb 133, Hct 40, platelets 63,000. Cytogenetics reveal t(15;17). What type of AML is this patient likely to have?

A. AML-M0
B. AML-M4
C. AML-M3 — Acute promyelocytic leukemia
D. AML-M6

[expand] Answer: C. AML-M3 — Acute promyelocytic leukemia

Explanation: t(15;17) is the pathognomonic genetic abnormality of APL (AML-M3). Low platelets (63,000) are common in APL due to DIC. Normal to mildly elevated WBC (9,100) is consistent with APL which can present with low, normal, or high WBC. This is a medical emergency requiring immediate ATRA initiation even before genetic confirmation. Diagnosis must be confirmed with FISH/PCR for PML-RARA and DIC panel (fibrinogen, D-dimer, PT/aPTT) must be monitored.

[/expand]

RO is a 44-year-old female with AML; t(8;21), NPM1 negative, FLT3 negative. Which is the most appropriate treatment?

A. 7+3 plus venetoclax
B. 7+3 plus gemtuzumab
C. Liposomal cytarabine and daunorubicin
D. Azacitidine and venetoclax

[expand] Answer: B. 7+3 plus gemtuzumab

Explanation: RO has t(8;21) which is CBF-AML — a favorable-risk subtype. For fit patients with favorable-risk cytogenetics, NCCN prefers adding gemtuzumab ozogamicin to the standard "7+3" induction backbone, as clinical meta-analyses have demonstrated the greatest benefit in this population. 7+3 + venetoclax is not a current standard of care for induction. Liposomal CPX-351 is for secondary AML in older patients, not de novo CBF-AML in a 44-year-old. Azacitidine + venetoclax is for older/unfit patients, not applicable here.

[/expand]

Ten days after achieving CR from induction with 7+3 + gemtuzumab, RO is to receive post-remission therapy. Which is most appropriate?

A. Azacitidine and venetoclax
B. Intermediate-dose cytarabine, daunorubicin, and gemtuzumab
C. Liposomal daunorubicin and cytarabine
D. 5+2 with gemtuzumab

[expand]Answer: B. Intermediate-dose cytarabine, daunorubicin, and gemtuzumab

Explanation: The protocol continuity rule requires consolidation to match the induction protocol. RO's induction was based on the ALFA-0701 study (7+3 + fractionated gemtuzumab), which uses intermediate-dose cytarabine + daunorubicin + gemtuzumab for consolidation. Azacitidine + venetoclax or liposomal CPX-351 consolidation would only be appropriate if those regimens were used during induction. 5+2 is for patients with residual blasts after induction.

[/expand]

RO is a 64-year-old female with secondary AML (history of DLBCL treated with R-CHOP 8 years ago), del(7), CD33+, FLT3 negative. She is highly fit. Which is the most appropriate treatment?

A. 7+3 with daunorubicin 45 mg/m²
B. 7+3 with daunorubicin 90 mg/m²
C. Liposomal cytarabine and daunorubicin plus gemtuzumab
D. Liposomal cytarabine and daunorubicin

[expand] Answer: D. Liposomal cytarabine and daunorubicin (CPX-351)

Explanation: RO has secondary AML (from prior R-CHOP therapy) and is 64 years old. For fit patients aged 60–75 with secondary AML or MDS-related changes, CPX-351 (liposomal daunorubicin/cytarabine) is a Category 1 recommendation demonstrating superior OS compared to standard 7+3. Adding gemtuzumab is not recommended as patients with secondary AML or poor-risk cytogenetics like del(7) do not respond well to it, and this combination has not been adequately studied with the liposomal backbone.

[/expand]

Ten days after achieving CR from CPX-351 induction, RO is to receive post-remission therapy. Which is most appropriate?

A. Cytarabine 3,000 mg/m² Q12h on days 1, 3, 5
B. Cytarabine 1,000 mg/m² + gemtuzumab 3 mg/m²
C. Liposomal daunorubicin 29 mg/m² and cytarabine 65 mg/m² on days 1 and 3
D. 5+2 (cytarabine × 5 days + daunorubicin days 1, 2)

[expand] Answer: C. Liposomal daunorubicin 29 mg/m² and cytarabine 65 mg/m² on days 1 and 3

Explanation: Protocol continuity rule: RO achieved CR using CPX-351 induction. Guidelines recommend consolidation with the same liposomal formulation at the approved consolidation doses (daunorubicin 29 mg/m² + cytarabine 65 mg/m² on days 1 and 3). This regimen demonstrated OS benefit in older patients with secondary AML in the phase III trial. HiDAC (A) was not studied in combination with liposomal induction. Intermediate-dose cytarabine + gemtuzumab (B) is for ALFA-0701 protocol patients. Standard 5+2 (D) was the inferior comparator arm in clinical trials.

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LJ is a 62-year-old female with AML — complex karyotype, IDH1 mutation, CD33+. She is highly fit (training for a marathon). Which is most appropriate?

A. Gemtuzumab ozogamicin
B. Ivosidenib
C. Azacitidine + venetoclax
D. Decitabine + enasidenib

[expand] Answer: C. Azacitidine + venetoclax

Explanation: LJ has adverse/complex karyotype AML. For patients over 60 with unfavorable cytogenetics, azacitidine + venetoclax is a preferred NCCN recommendation over intensive 7+3, typically yielding better responses in this risk group. While she has an IDH1 mutation, single-agent ivosidenib (B) is generally reserved for elderly patients unfit for more intensive regimens. Gemtuzumab (A) has significantly reduced efficacy in adverse-risk and complex karyotype AML. Decitabine + enasidenib (D) is incorrect as enasidenib targets IDH2, not IDH1, and this combination is not an NCCN recommendation.

[/expand]

LJ is a 79-year-old female with AML and an IDH1 mutation, CD33+, no comorbidities. Which is most appropriate?

A. Gemtuzumab ozogamicin
B. Venetoclax
C. Azacitidine + ivosidenib
D. Decitabine + enasidenib

[expand] Answer: C. Azacitidine + ivosidenib

Explanation: LJ has a confirmed IDH1 mutation and is 79 years old. The AGILE Phase III trial demonstrated that azacitidine + ivosidenib significantly improved median OS (24 vs. 7.9 months) compared to azacitidine alone in unfit/elderly patients with IDH1-mutated AML and is an NCCN Category 1 recommendation. Venetoclax (B) must always be used in combination — never as a single agent. Enasidenib (D) targets IDH2, not IDH1 — do not mix these up. Gemtuzumab (A) is not an NCCN-preferred therapy in this setting.

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SB is a 55-year-old female with relapsed AML following CPX-351 + gemtuzumab clinical trial. Normal karyotype; FLT3 negative, NPM1 negative, IDH1 negative. Which is most appropriate?

A. Midostaurin
B. FLAG-IDA + ivosidenib
C. MEC
D. Gilteritinib

[expand] Answer: C. MEC (mitoxantrone + etoposide + cytarabine)

Explanation: SB has no targetable mutations (FLT3 negative, IDH1 negative). MEC is the established intensive salvage regimen for patients without targetable molecular abnormalities. Gilteritinib (D) is for FLT3-mutated R/R AML — not applicable here. Ivosidenib targets IDH1 — also not applicable. Midostaurin (A) is ONLY used in the frontline setting in combination with 7+3 and is NOT a salvage agent.

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AML is said to have evolved from MDS if dysplasia is present in:

a. More than 50% of cells
b. More than 25% of cells
c. More than 30% of cells
d. More than 20% of cells

[expand] Answer: a. More than 50% of cells

Explanation: The specific morphologic criteria for identifying multilineage dysplasia — characterizing AML as having myelodysplasia-related changes — require dysplasia to be present in 50% or more of the cells in at least two myeloid lineages. This is distinct from the general 20% blast threshold for AML diagnosis and the > 10% dysplastic cells required for MDS diagnosis.

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Remission induction therapy for high-risk AML should be:

a. High-dose cytarabine
b. 3+7+3 induction including etoposide
c. High-dose cytarabine plus mitoxantrone
d. 3+7 induction (7+3)

[expand] Answer: d. 3+7 induction (7+3)

Explanation: The "7+3" regimen (7 days of cytarabine + 3 days of anthracycline) is a Category 1 recommendation for all risk groups including high-risk unfavorable cytogenetics. HiDAC is more typically the standard for consolidation, not induction. Adding etoposide to standard induction backbones has NOT been shown to improve outcomes. MEC (high-dose cytarabine + mitoxantrone) is a salvage therapy for relapsed/refractory AML, not frontline induction.

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True regarding treatment-related AML (t-AML):

a. Alkylating agents or radiation therapy typically present after a latency period of 5–7 years
b. Topoisomerase II inhibitors have a shorter latency period of 1–3 years
c. Patients with t-AML have poorer outcomes compared to de novo AML within the same risk group
d. All of the above

[expand] Answer: d. All of the above

Explanation: Alkylating agents or ionizing radiation lead to del(5) and del(7) with a median latency of 5–7 years (a is true). Topoisomerase II inhibitors lead to 11q23 mutations with a shorter latency of 1–3 years (b is true). Secondary/therapy-related AML is explicitly categorized as unfavorable risk with decreased OS compared to de novo AML due to higher likelihood of poor-risk cytogenetics and diminished ability to tolerate intensive therapy (c is true).

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PRACTICE QUESTIONS WITH ANSWERS AND EXPLANATIONS — ALL

DH is a 56-year-old male with Ph+ pre-B cell ALL. Which is the optimal remission induction therapy?

A. Tretinoin + arsenic trioxide
B. Blinatumomab
C. Clofarabine
D. HyperCVAD + dasatinib

[expand] Answer: D. HyperCVAD + dasatinib

Explanation: Ph+ ALL requires intensive chemotherapy combined with a TKI throughout all phases of treatment. HyperCVAD + dasatinib is the standard of care. Dasatinib is preferred because it has superior blood-brain barrier penetration, relevant given DH's headaches suggesting possible CNS involvement. Tretinoin + ATO is the standard for APL, not ALL. Blinatumomab is used for MRD-positive disease after ≥ 3 blocks of intensive chemotherapy or in relapsed/refractory settings — not as initial induction for a fit patient. Clofarabine is reserved for relapsed or refractory settings.

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After induction, DH's bone marrow biopsy shows positive MRD. Which is most appropriate?

A. Inotuzumab ozogamicin
B. Nelarabine
C. Continue current therapy / Continue HyperCVAD + TKI
D. Blinatumomab

[expand] Answer: C. Continue current therapy / Continue HyperCVAD + TKI

Explanation: Clinical data does not support switching therapy if MRD is positive immediately after induction. The BLAST trial criteria for adding blinatumomab require persistent MRD after at least 3 blocks of intensive chemotherapy — DH has only completed one cycle (induction). MRD negativity may still be achieved by continuing subsequent HyperCVAD cycles. Inotuzumab ozogamicin is reserved for fulminant relapsed/refractory disease, not early post-induction MRD. Nelarabine is specifically for T-ALL; DH has B-ALL.

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JG is a 33-year-old female with Ph− B-ALL who relapsed within 3 months of chemotherapy and is now receiving blinatumomab. She had 68% blasts prior to therapy. On day 2 of blinatumomab, she develops emesis with rigors, fever to 39°C, headache, and abnormal LFTs. Which best describes her symptoms?

A. Differentiation syndrome
B. Cerebellar toxicity
C. Urosepsis
D. Cytokine release syndrome

[expand] Answer: D. Cytokine release syndrome

Explanation: JG's presentation of fever (39°C), rigors, emesis, and elevated LFTs on day 2 of blinatumomab is characteristic of cytokine release syndrome (CRS). Her high disease burden (68% marrow blasts) is a major risk factor for CRS, resulting from widespread immune activation and a systemic cytokine storm. ICANS (neurotoxicity) presents with lethargy, confusion, or speech impairment — not fever and rigors. Differentiation syndrome is associated with ATRA/ATO in APL, not blinatumomab.

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JG has grade 1 CRS from blinatumomab. How should it be treated?

A. Supportive care
B. Stop blinatumomab
C. Tocilizumab
D. Dexamethasone

[expand]Answer: A. Supportive care

Explanation: Grade 1 CRS is managed with supportive care only, including maintenance fluids and empiric antibiotics if fever is present. Stopping blinatumomab is formally required for Grade 3+ CRS only. Tocilizumab is reserved for Grade 2+ CRS or Grade 1 persisting more than 3 days. Dexamethasone is for ICANS Grade 2+ or higher-grade CRS.

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JG now has Grade 2 ICANS — ICE score 6, lethargic but arousable, does not know the year or month. How should it be treated?

A. Supportive care
B. Permanently stop blinatumomab
C. Tocilizumab
D. Dexamethasone

[expand] Answer: D. Dexamethasone

Explanation: Grade 2 ICANS requires dexamethasone (steroids) plus supportive care. Tocilizumab treats CRS, NOT ICANS — this is a critical distinction. Supportive care alone is insufficient for Grade 2 neurotoxicity. Permanently stopping blinatumomab is not required for Grade 2 ICANS — the infusion may be paused and restarted once symptoms improve.

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SB is a 28-year-old female with relapsed B-ALL receiving tisagenlecleucel (CAR-T). Which medication should be initiated on the day of infusion?

A. Corticosteroids
B. Levofloxacin
C. Levetiracetam
D. Rasburicase

[expand] Answer: C. Levetiracetam

Explanation: CAR-T therapy is associated with ICANS (neurotoxicity). Seizure prophylaxis with levetiracetam 500–750 mg PO/IV every 12 hours is mandatory, starting on the day of the CAR-T infusion and continuing for at least 30 days. Corticosteroids must be AVOIDED prophylactically as they may impair CAR-T cell expansion and are reserved only for managing emergent toxicities. Rasburicase is for TLS management, not established as required on the infusion day in this scenario. Levofloxacin is not universally mandated by protocol for the day of infusion.

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DH has Ph+ pre-B cell ALL on HyperCVAD. Day 2 labs: WBC 42 x 10⁹/L, Creatinine 2.2, K 5.7, Phosphate 4.9, LDH 2810, Uric acid 8.6. Along with allopurinol, which is best to manage TLS risk?

A. Aggressive hydration (normal saline)
B. Rasburicase
C. Sodium polystyrene sulfonate
D. Consult for emergent renal dialysis

[expand] Answer: A. Aggressive hydration (normal saline)

Explanation: Aggressive IV hydration at 150–300 mL/hr is the most critical first intervention for TLS. It dilutes systemic electrolytes and maintains renal blood flow to facilitate excretion of potassium, phosphate, and uric acid. Rasburicase and sodium polystyrene sulfonate are added ONLY after IVF has been maximized. Renal dialysis is a last resort when medical management fails. DH's high WBC and significantly elevated LDH place him in the high-risk category for TLS.

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DH is a 55-year-old male with Ph− B-ALL. Which is the NCCN preferred protocol for his age group?

A. CALGB 10403
B. CALGB 9511 "Larson Protocol"
C. HyperCVAD
D. ECOG1910

[expand] Answer: D. ECOG1910

Explanation: DH is 55 years old — an adult, not an AYA. For adults with Ph− B-ALL, ECOG1910 (HyperCVAD + blinatumomab consolidation) is the only NCCN preferred regimen for patients aged 30–70. The ECOG1910 trial demonstrated that blinatumomab consolidation significantly improved OS compared to standard chemotherapy alone. CALGB 10403 is for the AYA population (15–39 years), not older adults. HyperCVAD and CALGB 9511 remain recommended options but are no longer the single preferred standard for this patient profile.

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DH is a 26-year-old male with Ph+ pre-B cell ALL. Which is the optimal remission induction therapy?

A. CALGB 10403
B. CALGB 9511
C. Mini-CVD + inotuzumab + ponatinib
D. HyperCVAD + ponatinib

[expand] Answer: D. HyperCVAD + ponatinib

Explanation: For Ph+ ALL, HyperCVAD combined with a TKI is the standard. Ponatinib has demonstrated exceptionally high complete molecular response rates when paired with HyperCVAD. CALGB 10403 and CALGB 9511 specifically excluded Ph+ ALL patients. Mini-CVD + inotuzumab + ponatinib was designed for older patients and has insufficient safety data for this combination, particularly due to the hepatotoxicity risk of combining inotuzumab with ponatinib in younger patients.

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Which drug in the ALL induction regimen does NOT affect complete remission rate?

a. Prednisolone
b. Vincristine
c. Daunorubicin
d. Asparaginase

[expand] Answer: d. Asparaginase

Explanation: The CR backbone for ALL induction = vincristine + corticosteroid + anthracycline. This triplet combination is sufficient to induce high rates of morphologic complete remission. Asparaginase does NOT contribute to the initial CR rate. However, asparaginase improves event-free survival and leukemia-free survival (LFS) and is critical for long-term outcomes, especially in pediatric-inspired protocols.

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KT is a 43-year-old female diagnosed with ALL. Which are the four key components of ALL treatment?

A. Induction therapy — CNS prophylaxis — Consolidation therapy — Maintenance therapy
B. Induction therapy — Radiation prophylaxis — Consolidation therapy — Maintenance therapy
C. Induction therapy — Radiation prophylaxis — CNS prophylaxis — Consolidation therapy
D. Induction therapy — Radiation prophylaxis — CNS prophylaxis — Maintenance therapy

[expand] Answer: A. Induction therapy — CNS prophylaxis — Consolidation therapy — Maintenance therapy

Explanation: The four essential pillars of ALL treatment are remission induction (4–6 weeks to eradicate bulk leukemic cells), CNS prophylaxis (mandatory intrathecal chemotherapy as the CNS is a sanctuary site where systemic chemo often fails to penetrate), consolidation/intensification (20–30 weeks to eliminate residual molecular disease), and maintenance (2+ years of lower-intensity therapy with oral 6-MP + weekly methotrexate to prevent recurrence). Radiation prophylaxis is NOT the standard CNS prophylaxis in adults.

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21. Which chromosomal abnormality is seen from topoisomerase II inhibitor-induced acute leukemia?

• A. 11q23 (37%)
• B. del 5 (21%)
• C. t(8;21) (9%)
• D. t(9;22) (23%)

[expand] Answer (A)

• Anthracyclines, etoposide, or teniposide all have the potential to induce the formation of leukemia.
• Leukemia typically occurs 2–3 years after drug exposure.
• Another abnormality is t(12;21).

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33. You are caring for a 24-year-old male with relapsed Philadelphia-negative ALL who is started on blinatumomab. Which of the following adverse effects are associated with this medication?

• A. Headache (6%)
• B. Tremors (4%)
• C. Disseminated intravascular coagulation (5%)
• D. All of the above (85%)

[expand] Answer (D)

• Blintumomab is a bispecific T-cell engager (BiTE) that targets CD3 on B-cells.
• It has a black box warning for life-threatening cytokine release syndrome (including fever, headache, nausea, asthenia, hypotension, increased transaminases, elevated total bilirubin, and DIC) and neurotoxicity (tremors, headache, confusion).
• Patients who receive blinatumomab should be closely monitored for signs of cytokine release syndrome and neurotoxicity.
• For patients who experience cytokine release syndrome and neurological toxicity, bilantumumab may need to be held or discontinued depending on the grade of the toxicity. If the infusion is interrupted for ≥ 4 hours, patients should be premedicated with dexamethasone 20 mg one hour before restarting bilantumumab.

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Which chromosomal abnormality is seen from alkylator induced acute leukemia?

• A. 21q22 (20%)
• B. del 5 (36%)
• C. 18(2;21) (21%)
• D. t(9;22) (23%)

[expand] Answer (B)

• Alkylator induced acute leukemias typically occur 3-8 years after drug exposure.
• Chromosomal aberrations seen include monosomy 5, 7, 11 and 17.

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• A JD should receive leucovorin (LV) only if the MTX level fails to go below a micromol/L after 48 hours. (9%)
• B The combination of TMP/SMX and high dose MTX should be avoided due to an increased risk for myelosuppression and nephrotoxicity. (54%)
• C Famotidine may inhibit MTX clearance so should be switched to a proton pump inhibitor such as pantoprazole which will not interact with MTX. (7%)
• D JD should receive leucovorin (LV) to prevent MTX-induced nephrotoxicity. (31%)

[expand] Answer (B)

• Concomitant use of high-dose MTX with TMP/SMX may result in severe toxicities via the following mechanisms:
  • Both drugs inhibit dihydrofolate reductase (DHFR), which may increase the risk of myelosuppression. Note it is the trimethoprim component of Bactrim that is known to inhibit DHFR similar to methotrexate.
  • Both drugs potentially cause nephrotoxicity, which may increase levels of both drugs due to impaired renal excretion.
  • Due to competitive protein binding and reduced tubular secretion, TMP/SMX can decrease MTX excretion by ~50% and increase free MTX levels in the blood by ~30%.
• High-dose methotrexate is lethal unless administered with LV rescue. MTX inhibits DHFR and depletes reduced folate while LV restores these depleted stores and enables DNA synthesis. If methotrexate clearance is delayed or impaired, the dose of LV can be increased.
• Concomitant use of high-dose MTX with PPIs such as omeprazole, esomeprazole, and pantoprazole may decrease methotrexate clearance and lead to increased toxicities. Famotidine does not interact with MTX.
• LV does not prevent MTX-induced nephrotoxicity. MTX-induced nephrotoxicity is caused by the precipitation of MTX and its metabolites in the renal tubules or via direct kidney injury caused by MTX. Before the start of MTX infusion and continued afterward, patients should receive aggressive IV hydration with urinary alkalization (sodium bicarbonate added to IV fluids to maintain urine pH > 7) to increase solubility and clearance of MTX and its metabolites.
• High-dose MTX should be given with standard LV rescue. Aggressive hydration and urinary alkalization should also be maintained to prevent MTX-induced nephrotoxicity. MTX has several significant drug interactions that interfere with its renal excretion, such as TMP/SMX.
• Common drug-drug interactions with MTX include TMP-SMX, penicillins and cephalosporins, and NSAIDs.

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116. A patient with newly diagnosed ALL is started on hyper-CVAD induction chemotherapy and subsequently develops hyponatremia. Which of the following agents in the hyper-CVAD regimen can lead to this side effect?

121. ALI is a 33 year old man diagnosed with acute promyelocytic leukemia and is started on tretinoin (Vesanoid). In your evaluation of him today you found out he developed a fever, pulmonary infiltrates, and pleural effusions. His WBC = 11.4 x10^9/L with a differential of 44% segmented neutrophils, 22% lymphocytes, 33% promyelocytes, 1% eosinophils. What therapy do you want to start?

• A Cefepime 2 g IV q8h (39%)
• B Dexamethasone 10 mg IV BID (47%)
• C Cytarabine + idarubicin chemotherapy (6%)
• D No therapy is indicated (8%)

[expand] Answer (B)

• This patient most likely is developing acute promyelocytic differentiation syndrome.
• Patients may present with fever with an elevated WBC >100x10^9/L, shortness of breath, weight gain, hypoxia, pleural and pericardial effusions.
• Treatment of differentiation syndrome requires dexamethasone 10 mg IV BID x 3–5 days then taper over 2 weeks. Temporary cessation of tretinoin is prudent in patients with significant hypoxia.

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