A phase I-II study of rituximab, ifosfamide, mitoxantrone and etoposide (R-IME) for B cell non-Hodgkin's lymphoma prior to and after high-dose chemotherapy and autologous stem cell transplantation (HDC-ASCT).

This phase I-II study describes the safety of rituximab, ifosfamide, mitoxantrone and etoposide (R-IME) as an induction regimen prior to high-dose chemotherapy and autologous stem cell transplantation (HDC-ASCT), and rituximab given post-HDC-ASCT for B cell non-Hodgkins's lymphoma. This study also measured the effect on disease burden and stem cell contamination. Patients with relapsed, refractory or poor risk B cell lymphomas were eligible. Patients were treated with two cycles of R-IME; all non-progressing patients under-went a third cycle and peripheral blood stem cell (PBSC) collection. Patients underwent HDC-ASCT and those patients in remission after HDC-ASCT were treated with four additional doses of rituximab. Tumor cell contamination was measured at baseline and in the PBSC. Serial immunoglobulin levels were measured. Patients were followed for time to treatment failure (TTF) and overall survival (OS). Thirty-two patients were enrolled. Thirty patients had at least stable disease after two cycles of R-IME. Twenty-nine underwent stem cell collection. The response rate to R-IME induction was 77% (20/26) with 35% (9/26) complete response(CR). Stem cell mobilization was successful in 93% (27/29) of patients. The response rate to R-IME induction and HDC-ASCT was 95% with a confirmed CR of 68%. Median follow-up was 28 months; the median TTFand OS have not been reached. There was a significant decline in stem cell tumor cell contamination and a significant decline in IgG without an increase in infections. Forty-three per cent of patients had transient neutropenia after post-transplant rituximab. R-IME is an effective cytoreductive and mobilization regimen. There appears to be a reduction in the number of lymphoma cells in the stem cell product and the toxicity is manageable.