The largest randomized trial in asymptomatic patients with smoldering multiple myeloma suggests that lenalidomide, a cancer drug, may delay the onset of bone and other myeloma-related organ damage. Results of the study, which was conducted by the Eastern Cooperative Oncology Group and funded by the National Cancer Institute, were published Friday, October 25, in the Journal of Clinical Oncology.

"Our findings are in line with a smaller trial in 2015 by researchers in Spain," says Vincent Rajkumar, MD, a Mayo Clinic hematologist and senior author of the paper. "In conjunction with the Spanish data, our findings support early therapy for patients with high-risk smoldering multiple myeloma."

The current standard of care for smoldering multiple myeloma is observation without therapy. "Early treatment with lenalidomide delays progression to symptomatic myeloma and can prevent damage to organs that occurs in multiple myeloma," says Dr. Rajkumar.

The study included 182 patients, 92 of whom received lenalidomide. The other 90 patients did not receive the drug but were observed, as in common practice.

Almost half of the patients receiving the drug responded to therapy, while no change was reported among patients who were observed without treatment. The time to disease progression from symptomatic myeloma was significantly longer in patients receiving lenalidomide, compared to patients who did not receive therapy. "Six patients in the study died—two in the group receiving lenalidomide and

four in the observation group," says Dr. Rajkumar. "It is too early to determine the impact of treatment on overall survival."

Dr. Rajkumar says serious adverse events occurred in 28% of patients on lenalidomide, but he says those events were considered manageable with dose reduction.

"These results, in combination with the findings in the 2015 Spanish study, support a change in the standard of care for intermediate and high-risk smoldering myeloma patients," says Dr. Rajkumar. "We show that it is possible to delay progression to multiple myeloma, a serious cancer with significant morbidity, by early therapy administered when the disease is still asymptomatic."

The Spanish study involved two drugs—lenalidomide and dexamethasone, a steroid—and found that early therapy delayed progression and also improved overall survival. But the findings did not lead to a change in practice, partly because it was not clear whether the beneficial effect was due to the therapeutic effect of the drugs independently or in Dr. Rajkumar says the study, involving researchers from across the US, shows that lenalidomide alone has a similar effect of delaying disease progression.