Heavily pretreated and refractory patients with multiple myeloma had encouraging efficacy results with daratumumab monotherapy. These results, from an open-label phase 2 trial, were recently published in The Lancet (doi:10.1016/S0140-6736(15)01120-4).
Daratumumab was approved in November 2015 for patients with multiple myeloma who had received at least 3 prior lines of therapy including a proteasome inhibitor and an immunomodulatory agent, or who did not respond to both a proteasome inhibitor and an immunomodulatory agent. It is a monoclonal antibody directed at CD38.
“The responses we saw in clinical trials that led to rapid approval were striking, especially considering that these patients received a median of 5 prior lines of therapy,” said Sagar Lonial, MD, of Winship Cancer Institute of Emory University in Atlanta, Georgia, and first author of the study.
“It appears the novel mechanism of action for daratumumab may play an important role in its single-agent activity among this group of advanced-stage multiple myeloma patients.”
The study reported data from 106 patients, and these patients had received a median of 5 previous lines of therapy. Overall responses occurred in 31 patients, including a complete response in 3 patients, a very good partial response in 10 patients, and a partial response in 18 patients.
The responses had a median duration of 7.4 months, and median progression-free survival was 3.7 months. When the data was analyzed, the median overall survival was 17.5 months.
The most common adverse events with daratumumab treatment were fatigue in 40% of the patients treated and anemia in 33%. No patients discontinued the drug due to adverse events.
“This represents the first single-agent activity we have for a monoclonal antibody in treating multiple myeloma. The future hope for daratumumab is in our ability to bring this active agent to earlier lines of therapy and combine it with drugs where you may get synergy,” said Lonial.