Adding Darzalex (daratumumab) to standard care therapies continues to show improved effectiveness in treating relapsed or refractory multiple myeloma, with no related toxicity, according to updated results from the ongoing Phase 3 POLLUX study (NCT02076009) and Phase 3 CASTOR study (NCT02136134).
The findings will be presented June 5 at the the 2017 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago. The two posters are titled “Daratumumab, lenalidomide, and dexamethasone (DRd) vs lenalidomide and dexamethasone (Rd) in relapsed or refractory multiple myeloma (RRMM): Efficacy and safety update (POLLUX)” and “Daratumumab, bortezomib and dexamethasone (DVd) vs bortezomib and dexamethasone (Vd) in relapsed or refractory multiple myeloma (RRMM): Efficacy and safety update (CASTOR).”
Combined use of Janssen Biotech‘s Darzalex with either Revlimid (lenalidomide) and dexamethasone, or Velcade (bortezomib) and dexamethasone, was approved for the treatment of multiple myeloma patients who have not responded to prior treatments by the U.S. Food and Drug Administration in November 2016, and by the European Commission in May 2017.
The approval was based on data from the CASTOR and POLLUX Phase 3 trials, and researchers are now presenting updated results from both these trials.
After 25 months of follow-up in the POLLUX trial, which included 569 multiple myeloma patients with relapsed or refractory disease, researchers found that adding Darzalex to the standard care regimen of Revlimid and dexamethasone reduced the risk of disease progression or death by 63 percent, compared to Revlimid and dexamethasone alone. It also improved the overall treatment response rate by 1.2 fold.
Results of the CASTOR study revealed similar beneficial effect of adding Darzalex to the standard of care, but this time with Velcade and dexamethasone. Risk of disease progression or death decreased by 63 percent in patients treated with the triple therapy. In addition, the overall response rate for those adding Darzalex was 84 percent, compared to 63 percent for those who received the standard therapy.
Safety profiles of the triple therapies remain as previously reported, with no new adverse events associated.
An additional study, addressing patients’ responses to the triple therapies, stratified by genetic risk status, will also be presented at the meeting. The study is titled “Efficacy of daratumumab in combination with lenalidomide plus dexamethasone (DRd) or bortezomib plus dexamethasone (DVd) in relapsed or refractory multiple myeloma (RRMM) based on cytogenetic risk status.”
It shows that the beneficial effects of additional Darzalex are independent of the genetic status presented by the patients: no clinical meaningful differences were observed between those with high or low genetic risk profiles receiving triple therapy.
These results provide further evidence on the improved efficacy of adding Darzalex to standard care regimens for treatment of multiple myeloma.