Comparison of interferon tolerance after autologous bone marrow or peripheral blood stem cell transplants for myeloma patients who have responded to induction therapy.

Interferon (INF) has been incorporated as part of maintenance therapy after high dose treatment in order to make remissions more durable. In this study we have compared peripheral blood stem cell transplant (PBSCT) versus autologous bone marrow transplant (ABMT) with respect to INF tolerance. Thirty nine PBSCT patients have been compared to 37 ABMT patients for INF tolerance. This is followed by a comparison of 15 PBSCT patients versus 21 ABMT patients for engraftment details, response and survival. INF was started at a median of 61 days in the PBSCT and 58 days in the ABMT patients (P = NS). It was well tolerated in both groups without a significant difference in toxicity in the two arms. Engraftment was more rapid in the PBSCT patients with platelet recovery being significantly faster. Response and survival showed a favourable trend for ABMT patients though statistical significance was not reached and the cost of PBSCT was 12% cheaper. We were thus able to conclude that PBSCT grafts were as durable and could tolerate INF just as well as ABMT. Engraftment was more rapid and the procedure of PBSCT was also cheaper. Further studies with a larger group of patients will be required before comments on the efficacy of treatment can be made.