Researchers from Janssen Research & Development presented promising interim results from the Phase 3 MMY3004 (CASTOR) clinical trial, assessing the immunotherapy drug daratumumab (Darzalex) against standard of care in previously treated multiple myeloma patients, at the recent American Society of Clinical Oncology (ASCO) 2016 Annual Meeting in Chicago.
Specifically, the ongoing trial (NCT02136134) showed that a treatment protocol combining daratumumab, the protease inhibitor bortezomib, and the corticosteroid dexamethasone, resulted in a 61 percent reduction in risk of disease progression or death (progression-free survival, or PFS) compared to standard care — bortezomib and dexamethasone alone — in multiple myeloma patients who had received at least two prior lines of therapy. PFS, the trial’s primary endpoint, was measured at a median follow-up of 7.4 months. A final PFS endpoint has not been reached, and the trial is expected to conclude in March 2017.
Likewise, a significant improvement in overall response rate (ORR), a secondary trial outcome, was also seen in patients treated with the daratumumab combination compared to those receiving standard care, with a doubling in complete response (19 percent vs. 9 percent, respectively) and a doubling in rates of very good partial response (59 percent vs. 29 percent), Janssen said in a company press release.
“We saw clinically meaningful improvements in progression-free survival and overall response rates with daratumumab when combined with standard of care. These compelling Phase 3 results demonstrate that a regimen built on daratumumab deepens clinical responses and help to underscore its potential for multiple myeloma patients who have been previously treated,” Dr. Antonio Palumbo, MD, Myeloma Unit Chief, Department of Oncology at University of Torino, Italy, said in the release.
Based on these positive findings, part of pre-planned interim analysis, the trial was unblinded and all participants were offered the option of moving into the daratumumab arm upon confirmed disease progression. The unblinding came at the recommendation of an independent committee monitoring the trial.
“We’re excited to share these data with the oncology community at ASCO, just two months after an Independent Data Monitoring Committee recommended unblinding the study,” said Dr. Peter F. Lebowitz, MD, PhD, Oncology Therapeutic Area Head at Janssen.
Results also showed a safety profile consistent with treatment utilization of daratumumab and its known safety profile. The most common adverse events observed were thrombocytopenia, peripheral sensory neuropathy, and anemia.
Daratumumab (Darzalex) was approved by the U.S. Food and Drug Administration (FDA) for the treatment of multiple myeloma patients who have received at least three prior lines of therapy, including a proteasome inhibitor (PI) and an immunomodulatory agent, or who are double-refractory to a PI and an immunomodulatory agent, in November 2015.
The presentation was given in a Plenary Session at the ASCO meeting, which concluded on June 7.