Autologous Hematopoietic Stem Cell Transplantation

Autologous Hematopoietic Stem Cell Transplantation (Auto-HSCT / ASCT)

Definition

• A procedure in which a patient’s own hematopoietic stem cells are collected, stored, and reinfused after myeloablative or high-dose chemotherapy.
• Goal: allow delivery of otherwise lethal chemotherapy doses while restoring marrow function.
• Unlike allogeneic HSCT, there is no donor → no GVHD, but also no graft-versus-tumor effect.

Indications (Major Uses in Oncology)

• Multiple Myeloma – standard frontline consolidation in eligible patients (usually <70, good performance status) with high-dose melphalan (MEL200) conditioning.
• Relapsed/Refractory Lymphomas:
  • Diffuse large B-cell lymphoma (DLBCL)
  • Hodgkin lymphoma (HL)
  • Mantle cell lymphoma (MCL)
  • Some follicular lymphomas (selected cases)
• Solid tumors (less common): germ cell tumors, neuroblastoma (pediatrics).

Process

1. Mobilization & Collection
   • G-CSF ± plerixafor (for poor mobilizers)
   • ± Cyclophosphamide-based chemo-mobilization
   • Collected by apheresis (goal ≥2–5 × 10⁶ CD34+ cells/kg)
2. Cryopreservation
   • Stem cells frozen (DMSO cryoprotectant) until reinfusion
3. Conditioning Chemotherapy (Myeloablative)
   • Multiple Myeloma → Melphalan 200 mg/m² (MEL200)
   • Lymphoma → BEAM regimen (BCNU, Etoposide, Ara-C, Melphalan)
   • Other regimens: CBV, TBC, BuMel, etc.
4. Stem Cell Infusion (Day 0)
   • Reinfused like a blood transfusion
   • Common side effects: DMSO-related (nausea, vomiting, garlic/cream-corn odor, bradycardia, hypotension, flushing)
5. Engraftment
   • Neutrophil recovery usually day +10 to +14
   • Platelet recovery: variable (weeks)
   • Supportive care during aplasia

Supportive Care (Pharmacist Focus)

• Antimicrobial prophylaxis:
  • Antiviral: acyclovir
  • Antifungal: fluconazole (or mold-active azole if high risk)
  • PCP: TMP-SMX (start post-engraftment)
• Growth factor: Filgrastim post-infusion until ANC recovery
• Transfusions: PRBCs, platelets as needed
• Mucositis prevention: Oral cryotherapy with high-dose melphalan
• Antiemetics: 5-HT3 antagonist, NK1 antagonist, dexamethasone
• Fertility: Consider preservation before ASCT
• Vaccination: Restart 6–12 months post-transplant

Advantages vs Allogeneic HSCT

Lower treatment-related mortality

No GVHD

Higher risk of relapse (no graft-versus-tumor effect)

Complications

• Early (0–30 days): pancytopenia, mucositis, neutropenic fever, infections
• Intermediate (1–6 months): infections, delayed cytopenias
• Late (>6 months): relapse, secondary malignancies, organ toxicities

Pharmacist Key Monitoring Points

• Conditioning regimen dosing (renal/hepatic adjustment if needed)
• Busulfan PK monitoring (if used in regimen)
• Avoid interacting drugs (e.g., azoles ↑ busulfan exposure)
• Ensure tocilizumab stocked in center if CAR T used post-ASCT relapse
• Patient education: report fever, RUQ pain (VOD risk), mucositis management, infection prevention