Add-on ixazomib does not improve cyclophosphamide-dexamethasone combo in frail MM patients

The addition of ixazomib to cyclophosphamide-dexamethasone (CD) treatment does not seem to result in better survival and response rates in patients with newly diagnosed and relapsed multiple myeloma (MM), a recent study has found.

The randomized, controlled, open-label, multicentre phase II trial enrolled 112 patients who had previously been treated with thalidomide, lenalidomide, and a proteasome inhibitor. Fifty-four patients received CD only, while 58 were treated with additional ixazomib (ICD). The primary clinical activity outcome measure was progression-free survival (PFS).

A total of 110 patients completed the median follow-up of 10.7 months. According to a composite of age, Charlson Comorbidity Index, and Eastern Cooperative Oncology Group performance status, 73.6 percent of patients were frail.

Median PFS was 5.6 months in the ICD group, not significantly different than the 6.7-month outcome in CD comparators. The resulting risk estimate, as calculated by Cox proportional hazards models, was likewise statistically comparable between arms (hazard ratio [HR], 1.21, 80 percent confidence interval [CI], 0.9–1.6; p=0.3634).

A similar pattern was reported for overall survival (OS; ICD vs CD: 14.1 vs 19.1 months; HR, 1.52, 80 percent CI, 1.06–2.18; p=0.1346). Frailty was also not deemed to be a significant correlate of PFS and OS, with survival rates remaining comparable between frailty and treatment groups.

“The results of this study show that, at least in the frail and advanced patient population enrolled, the inexpensive and all-oral combination of CD can indeed be associated with satisfactory responses, a finding that is particularly relevant for MM patients who do not have access to costly novel drug combinations,” the researchers said.