Ixazomib Promising Maintenance Therapy Option for Multiple Myeloma

Adam D. Cohen, MD, Director, Myeloma Immunotherapy, Abramson Cancer Center of the University of Pennsylvania, Philadelphia, shares data from a study looking at ixazomib as a maintenance therapy option for patients with multiple myeloma.

Transcript

The last interesting abstract I'll highlight was the Abstract 301 by Dimopoulos, et al., looking at a new maintenance option for myeloma. Several studies have shown that lenalidomide maintenance can improve progression-free, and in a meta-analysis overall survival after stem cell transplant.

This was a trial that looked at ixazomib maintenance. Ixazomib is an oral proteasome inhibitor, very similar structurally and in terms of efficacy to bortezomib, but with less neuropathy. In this study, patients who had completed induction therapy, autologous transplant, and had at least a partial remission were randomized to oral ixazomib given day 1, 8, and 15 of a 28-day cycle versus a placebo.

Both either ixazomib or placebo were given until progression. The primary endpoint was progression-free survival in this study. The bottom-line, what they found with the median follow-up of about 31 months was that ixazomib did improve progression-free survival compared to the placebo and met its primary endpoint.

The median PFS was 26.5 months for ixazomib versus 21.3 months for placebo with a hazard ratio of 0.72. While I think this was a positive study, there was some disappointment in the myeloma community that the magnitude of the benefit wasn't greater.

For comparison's sake, the lenalidomide study, the hazard ratio was closer to the 0.5. There was almost a doubling of progression-free survival with lenalidomide maintenance versus placebo, and not as much of a benefit was seen here.

Nonetheless, I do think this is an important study. It's the first randomized trial really showing a benefit of proteasome inhibitor maintenance in myeloma. Certainly, the first for an oral proteasome inhibitor. I think this provides another option for patients who are lenalidomide-intolerant or have allergies to it.

I think there are further studies that are ongoing that will look at combining ixazomib with lenalidomide versus lenalidomide alone. We'll take a look and see if dual maintenance is better than single.