Johnson & Johnson’s Darzalex has comfortably been the only CD38 multiple myeloma drug on the market for years until Sanofi hit the scene last year with Sarclisa. Now, just as the competition’s slated to intensify, the U.S. company is building its case with new patient survival data.

Adding Darzalex to Bristol Myers Squibb’s Revlimid and steroid dexamethasone (Rd) could slash the risk of death by 32% in newly diagnosed multiple myeloma patients ineligible to receive stem cell transplants, J&J reported at the European Hematology Association’s virtual congress.

The survival benefit is “unprecedented” for an ageing myeloma population, almost all of whom were 65 years of age or older, said Craig Tendler, M.D., vice president of oncology clinical development and global medical affairs at J&J’s Janssen unit, during an interview.

The Darzalex-Rd regimen got its FDA go-ahead in transplant-ineligible patients in 2019 based on data from the same phase 3 MAIA trial showing it could pare down the risk of disease progression or death by 44% after a median follow-up of 28 months. Now, after 56.2 months of follow-up, over half of Darzalex patients were still alive without their disease worsening, a showing that’s again “unprecedented” for front-line myeloma treatment, Tendler said.

The entire set of results “strongly support” the Darzalex-Rd combo as a new standard of care for newly diagnosed, transplant-ineligible multiple myeloma patients, Thierry Facon, M.D., an investigator of the MAIA trial, said in a statement.

Darzalex does have another regimen approved for the same myeloma population. Darzalex combined with Takeda’s Velcade, melphalan and prednisone (VMP) reduced the risk of death by 40% in the phase 3 ALCYONE trial. But disease progression had already occurred in half of the patients on the Darzalex-VMP combo after about three years of follow-up, a much shorter period than the five-year mark the Darzalex-Rd regimen is approaching.

The two trials studied similar patient populations, Tendler said, but VMP was an old standard of care that’s not really used today in the U.S. Still, Tendler believes the two regimens may both have roles to play based on each patient’s ability to tolerate them. Whichever cocktail physicians choose, the two-phase 3 studies have confirmed the benefit of Darzalex in transplant-ineligible patients, he added.

But Sanofi’s rival CD38 antibody Sarclisa may soon be able to challenge Darzalex in the same front-line, transplant-ineligible population with the help of a more powerful backbone.

Currently allowed as a second-line treatment, Sarclisa is expected to have top-line data from the phase 3 IMROZ trial later this year. The trial is adding Sarclisa to a VRd cocktail of Velcade, Revlimid and dexamethasone, which has established itself as the standard-of-care first-line therapy for patients with myeloma.

Darzalex has its own VRd combo trials, dubbed PERSEUS and CEPHEUS, which are testing a newly approved under-the-skin version of the J&J drug called Darzalex Faspro. The CEPHEUS trial appears to have just completed its primary analysis, according to a listing on ClinicalTrials.gov.