Lenalidomide with or without dexamethasone as maintenance therapy produces similar overall survival (OS) among patients with relapsed or refractory multiple myeloma (RRMM) who respond to second-line lenalidomide plus dexamethasone induction therapy, according to a study published in Cancer Research.

Lenalidomide and dexamethasone combination therapy is approved for the treatment of RRMM and leads to improved survival outcomes and time to progression. Previous studies have demonstrated that maintenance therapy with lenalidomide alone is effective in newly diagnosed multiple myeloma (MM), but its role in RRMM requires further study.

For this study, researchers enrolled 133 lenalidomide-naive patients with MM into an observational, noninterventional study after first relapse. Patients received lenalidomide plus dexamethasone and also completed questionnaires regarding symptoms and treatment of adverse events (AEs). Patients in the observational study who achieved partial response (PR) or better were able to join a prospective phase 2 study; 62 patients were randomly assigned to receive prolonged treatment with lenalidomide alone or with dexamethasone.

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Eleven percent of patients in both studies had a complete response (CR); 31% of patients achieved very good partial response (VGPR) and 38% achieved PR. Of the 71 patients who did not enter the phase 2 study, 3% had CR, 18% had VGPR, and 39% had PR.

In the phase 2 study, the rate of disease progression after 2 years was 47% and 31% among patients treated with lenalidomide alone or in combination with dexamethasone, respectively, but this finding was insignificant.

After a median 36 month follow-up among surviving patients, the median time to progression was not reached among patients treated with lenalidomide plus dexamethasone and was 24.9 months with lenalidomide monotherapy.

The 3-year OS rate was 61% in the observational study and 73% among patients who entered the phase 2 study; both treatment arms in the phase 2 study had an OS rate of 73%. The OS rate was 55% among patients who achieved PR but did not enter the phase 2 study.

Long term lenalidomide treatment led to increased rates of neutropenia and thrombocytopenia, but were manageable.

The authors concluded that “prolonged treatment with [lenalidomide] with or without [dexamethasone] provides sustained, clinically relevant responses and demonstrates an acceptable safety profile.”

Reference

Lund J, Gruber A, Lauri B, et al. Lenalidomide versus lenalidomide + dexamethasone prolonged treatment after second-line lenalidomide + dexamethasone induction in multiple myeloma[published online April 19, 2018]. Cancer Med. doi: 10.1002/cam4.1422