High dose chemotherapy with autologous stem cell support for patients with histologically transformed B-cell non-Hodgkin lymphomas. A Norwegian multi centre phase II study.

We present a prospective phase II study of patients with relapse after chemotherapy showing transformation of follicular lymphoma to diffuse large B-cell lymphoma, performed before rituximab was included in standard treatment. Patients in complete (CR) or partial remission (PR) after salvage chemotherapy were eligible for high-dose chemotherapy with autologous stem cell support (HDT). Forty-seven patients from five Norwegian centres were included, of whom 30 (63%) received HDT. Eighteen (60%) achieved CR, seven (23%) PR and five (10%) had progressive disease following HDT. Median follow-up for the surviving patients was 75 months; median progression-free (PFS) and overall survival (OS) were 26 and 47 months, respectively. Median OS for all patients was 43 months, compared to only 10 months for patients not eligible for HDT. Patients receiving CD34(+) enriched/B-cell depleted grafts had inferior PFS and a trend for inferior OS compared to patients receiving non-purged grafts (Log Rank 0·025 and 0·151, respectively). In conclusion, two thirds of patients with transformation of follicular lymphoma were eligible for HDT. The majority of patients achieved CR and a considerable number had prolonged OS. The use of in vitro purged grafts did not result in a survival benefit compared to that of non-purged grafts.