Extended Follow-up of Autologous Bone Marrow Transplantation with 4-Hydroperoxycyclophosphamide (4-HC) Purging for Indolent or Transformed Non-Hodgkin Lymphomas

Autologous blood or marrow transplantation (ABMT) for low-grade lymphomas can prolong event-free survival (EFS) but requires long-term follow-up. We report one of the longest follow-ups to a prospective transplantation study in such diseases. On a phase II study, 80 patients with low-grade, transformed, or mantle cell lymphoma received ABMT with 4-hydroperoxycyclophosphamide (4-HC) purging as part of initial or salvage therapy. Diagnoses included nontransformed follicular lymphoma in 63% and transformed lymphoma in 15%. With 16.6-year median follow-up for survival, actuarial 10-year EFS and overall survival (OS) were 34% (95% confidence interval [CI], 25%-46%) and 45% (35%-57%). Median EFS and OS were 3.0 and 8.0 years. Early nonrelapse mortality incidence was 8%; myelodysplastic syndrome or leukemia incidence was 4%. Most relapses occurred within 3 years, with a median time to diagnosis of relapse of 1.8 years (range: 0.1-15.6 years). On multivariate analysis, age >50 years, ≥3 prior chemotherapy regimens, and ABMT after relapse were associated with significantly inferior survival. Fifteen patients (19%) were event-free >15 years after transplantation, raising the possibility of a plateau in the progression-free survival curve. Thus, 4-HC-purged ABMT can produce extended remissions in a subgroup of patients with indolent lymphomas.