Recent evidence suggests that patients with newly diagnosed multiple myeloma treated with high-dose melphalan therapy prior to undergoing autologous stem cell transplantation (ASCT) are more likely to achieve complete response when co-treated with bortezomib. Murielle Roussel and colleagues, from multiple French institutions, analyzed the synergistic effects of bortezomib (a reversible proteasome inhibitor) with melphalan on response to ASCT as part of a single-arm, open-label, Intergroupe Francophone du Myelome (IFM) phase II study. “To date, no conditioning regimen has proven to be more effective than high-dose melphalan, which is well tolerated, but ultimately not curative,” explains Roussel, the study's lead investigator.

...a higher percentage of matched patients achieved complete response in the Bor-HDM study...

The researchers enrolled 54 patients with newly diagnosed multiple myeloma scheduled to undergo ASCT and evaluated their clinical response at 3 months of follow-up. Roussel's team found that 32% of individuals treated with a combination of bortezomib and high-dose melphalan (Bor-HDM) achieved complete response, while 70% had a very good partial response.

To evaluate the effect of bortezomib on response to ASCT with that of a control cohort, the researchers matched 46 suitable participants from the Bor-HDM study with 115 eligible patients from the IFM 2005–01 trial who were treated with high-dose melphalan alone—initial evaluations and response criteria were identical in both trials. Overall, the investigators noted that a higher percentage of matched patients achieved complete response in the Bor-HDM study compared with those participating in the IFM 2005–01 trial (35% versus 11%, respectively).

Furthermore, the researchers stress that bortezomib therapy was well tolerated and no treatment-related mortality or increased toxicity was recorded. “These data give support for developing this Bor-HDM combination followed by ASCT,” concludes Roussel, who goes on to say “prospective randomized trials are needed to assess whether this combination regimen is effectively better than high-dose melphalan alone in the setting of induction therapies containing new drugs, and if it can enhance the depth of the response.”