Nonmyeloablative allogeneic hematopoietic cell transplantation in relapsed, refractory, and transformed indolent non-Hodgkin's lymphoma

Purpose: Few effective treatment options exist for chemotherapy-refractory indolent or transformed non-Hodgkin's lymphoma (NHL). We examined the outcome of nonmyeloablative allogeneic hematopoietic cell transplantation (HCT) in this setting. Patients and Methods: Sixty-two patients with indolent or transformed NHL were treated with allogeneic HCT from related (n = 34) or unrelated (n = 28) donors after conditioning with 2 Gy of total-body irradiation with or without fludarabine. Nine unrelated donors were mismatched for ≥ one HLA antigen. Sixteen patients had histologic transformation before HCT. Twenty patients (32%) had progressive disease after previous high-dose therapy with autologous HCT. Median age was 54 years, and patients had received a median of six lines of treatment before HCT. Median follow-up time after HCT was 36.6 months. Results: At 3 years, the estimated overall survival (OS) and progression-free survival (PFS) rates were 52% and 43%, respectively, for patients with indolent disease, and 18% and 21%, respectively, for patients with transformed disease. Patients with indolent disease and related donors (n = 26) had 3-year estimated OS and PFS rates of 67% and 54%, respectively. The incidences of grade 2 to 4 acute graft-versus-host disease (GVHD), grade 3 and 4 acute GVHD, and extensive chronic GVHD were 63%, 18%, and 47%, respectively. Among survivors, the median Karnofsky performance status at last follow-up was 85%. Conclusion: Nonmyeloablative allogeneic HCT can produce durable disease-free survival in patients with relapsed or refractory indolent NHL, even in this relatively elderly and heavily pretreated cohort. Outcomes were particularly good in patients with untransformed disease and related donors, whereas patients with transformed disease did poorly. Long-term survivors reported good overall functional status.