Introduction

In spite of the favourable results observed after autologous PBSCT in MM there is no clear plateau in the survival curve and eventually most patients relapse with a median EFS between 40–50 months postransplant. To improve these results and sustain remission, various maintenance treatments have been proposed with minimal and discrepant benefits. Interpheron alpha2b s.c. at low dose and steroids on alternate days, have demonstrated modest improvements in EFS and OS times (5–12 months) after standad-dose therapya but its role in the setting of high dose therapy (HDT) needs confirmation. Recently a new formulation of interpheron alpha2b is available conjugated with polietilenglicol (Pegintron®), that need only one dose weekly and has not been evaluated in MM. We present the preliminary and interim results of a spanish, open study, no comparative, multicentric with Pegintron® (Schering-Plough) as maintenance treatment after autologous PBSCT.

Patients y Methods

17 patients with MM received Pegintron® once wekly subcutaneously as maintenance treatment after favourable response post-HDT with autologous PBSCT when the engraftement was completed (7 CR and 10 PR). The initial dose was 15 mg/week x 2 week and this dose was escalated to 25 mg/week and then 35 mg/week. The final dose was adopted according clinical and hematological tolerance. Intermitent oral steroids were allowed. The maintenance treatment was continued until toxicity, relapse or progressión.

Results

Of the 17 patients included so far in the study, 2 patients suspended the treatment. One case by personal decision an the other for progression, 14 months after transplant. The remainder 15 patients follow the treatment with a median of 10.7± 5 months (1.5–18.6). Most patients received also zolendronate iv/months and oral low dose dexamethasone (20 mg x 4 x months) associated to Pegintron. Mild bone pain, “flu-lyke syndrome” and grade I thrombopenia and neutropenia, were the most common adverse effect.. The best tolerated dose was 15 mg/week. With the exception of one case, all patients maintain the response achieved with HDT with a median of 15 months (3–22) after transplant.

Comments and Conclusions

These prelimiar results show that maintenance treatment with a weekly dose of Interpheron-a2b conjugated with Polietilenglicol (Pegintron®) is effective and well tolerated after autologous PBSCT in MM. No major adverse effects were observed and no relevant negative effecst was presented on the autologous graft. Pegintron® could be an alternative to sc standar interpheron with the main advantage of therapy simplification (one dose weekly). More experience and longer follow up are needed to evaluate the role of this strategy in the global treatment of MM and new approaches for maintenance have to be investigated, including new drugs as bortezomib, thalidomide an lenalidomide, associated or not with bisphosphonates, Pegintron and steroids.

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