Autologous Stem Cell Transplantation

Autologous Stem Cell Transplantation (ASCT)

Definition

• A procedure where a patient’s own hematopoietic stem cells are collected, stored, and then reinfused after the patient receives high-dose chemotherapy (conditioning regimen, e.g., BEAM, MEL200, TBC, etc.).
• Unlike allogeneic SCT, no donor is used → eliminates risk of graft-versus-host disease (GVHD).

Indications (major oncology uses)

1. Hematologic Malignancies
   • Hodgkin lymphoma (relapsed/refractory)
   • Non-Hodgkin lymphoma (DLBCL, mantle cell, follicular)
   • Multiple myeloma (standard of care in transplant-eligible patients)
2. Other
   • Some solid tumors (rare, e.g., germ cell tumors)

Steps in ASCT

1. Mobilization & Collection
   • Growth factors: G-CSF (filgrastim, pegfilgrastim) ± plerixafor (CXCR4 inhibitor, for poor mobilizers)
   • Leukapheresis: Peripheral blood stem cells (PBSCs) collected
   • Goal: ≥ 2–5 × 10⁶ CD34+ cells/kg
2. Cryopreservation
   • Stem cells frozen (usually with DMSO as cryoprotectant) until reinfusion
3. Conditioning Chemotherapy
   • High-dose regimen (e.g., BEAM for lymphoma, Melphalan 200 mg/m² for myeloma)
   • Purpose: eradicate residual disease + marrow ablation
4. Stem Cell Infusion (“Day 0”)
   • Thawed stem cells reinfused IV (like a blood transfusion)
   • Side effect: DMSO toxicity → nausea, garlic/creamed-corn odor, bradycardia, hypotension
5. Engraftment & Recovery
   • Supportive care during aplastic phase (≈10–14 days)
   • Engraftment: recovery of ANC > 500/µL for 3 consecutive days

Supportive Care (Pharmacist Focus)

• Antimicrobial prophylaxis:
  • Bacterial: fluoroquinolones (sometimes)
  • Fungal: fluconazole (or posaconazole if high risk)
  • Viral: acyclovir
  • PCP: TMP-SMX post-engraftment
• Growth factors:
  • Filgrastim post-transplant to accelerate engraftment
• Transfusions:
  • Platelets and RBC support as needed
• Other considerations:
  • Cryotherapy with high-dose melphalan → reduces mucositis
  • Seizure prophylaxis with high-dose busulfan regimens
  • Fertility preservation counseling prior to ASCT
  • Vaccination re-initiation ~6–12 months post-ASCT

Advantages vs Allogeneic SCT

• Lower treatment-related mortality
• No GVHD
• No graft-versus-leukemia/lymphoma effect (relapse is main limitation)

Key Complications

• Early (first 30 days): mucositis, neutropenic fever, infections, organ toxicities
• Intermediate (1–6 months): infections (viral reactivations, fungal)
• Late (>6 months): relapse of primary disease, secondary malignancies