A Short Course of Standard Velcade/Dexamethasone Followed by Unlimited Weekly Maintenance Therapy Is an Effective Treatment in Relapsed/Refractory Multiple Myeloma.

Background: Bortezomib (B), known as Velcade, is a reversible proteasome inhibitor approved for relapsed/refractory multiple myeloma (RRMM) patients (pts). The standard of care protocol includes eight cycles of intravenous push (IVP) injections of B and oral dexamethasone (D), which increases the toxicity. Here, we describe the results of an open-label, phase II clinical trial employing only four cycles of B/D.

Methods: RRMM pts treated with at least one previous therapy qualified for the trial. Pts were treated with B 1.3 mg/m IVP or subcutaneous (SC) on day 1, 4, 8, and 11, followed by a 10-day rest, Q21 days for four cycles; followed by maintenance therapy with once weekly B 1.6 mg/m IVP or SC on day 1, 8, 15, and 22, followed by 13 days' rest, repeated Q36 day. Pts received D 20 mg on the days of and days after B. Pts with a complete response (CR) were removed. Those with a partial response (PR) or stable disease (SD) were placed on maintenance therapy until progressive disease (PD), unacceptable toxicity, or pts' decision to stop.

Results: A total of 24 pts were enrolled. CR was observed in six pts (25%), PR in eight pts (33%), and SD in nine pts (37.5%). Moreover, 14 of the 24 pts (58.3%) had PR or better. Four pts had PD during induction. The grade 3 toxicities included fatigue (58%), sensory neuropathy (54%), and thrombocytopenia (50%); the grade 4 toxicities were thrombocytopenia (12.5%), fatigue (12.5%), and sensory neuropathy (12.5%).

Conclusions: A short course of B/D, plus maintenance with B, is well tolerated in RRMM pts. Long-term maintenance with B/D could become an alternative to new agents.