Photo credit: "Plasmacytoma ultramini1" by Nephron - Own work. Licensed under CC BY-SA 3.0 via Commons.
Just two weeks after the FDA approved the first immunotherapy drug to treat multiple myeloma, a second immunotherapy drug, elotuzumab (Empliciti™), received approval yesterday to treat resistant forms of multiple myeloma in combination with other therapies.
Multiple myeloma is a blood cancer that causes plasma cells—which, normally, help the body fight infection and disease by making antibodies—to grow excessively and crowd out healthy blood cells. This disease is extremely hard to treat, with a 5-year survival rate of 50% after diagnosis, and recurrence is common.
This makes new and improved therapies for multiple myeloma a high priority for clinicians and scientists, especially considering that 27,000 new cases are expected in the United States this year alone. The FDA approval was based on the results of the ELOQUENT-2 study, a phase III trial which examined elotuzumab’s effects on patients with multiple myeloma that had been treated up to three times previously.
When combined with the two standard chemotherapy drugs used to treat myeloma, elotuzumab led to a 30% reduction in the risk of disease progression and death. After 2 years on the elotuzumab regimen, 41% of patients survived without disease progression as compared to 27% of those without the drug. Additionally, the overall response rates were 78.5% versus 65.5% in patients receiving elotuzumab versus those receiving the standard chemotherapy drugs. The beneficial effects of elotuzumab “seemed to get bigger over time, which really speaks to the power of this immune-based approach,” according to Sagar Lonial, M.D., the lead author of the ELOQUENT-2 study.
Importantly, the addition of elotuzumab did not increase the occurrence of adverse effects, such as fatigue and diarrhea, in response to treatment.
While daratumumab (Darzalex®) first showed the potential of immunotherapy in treating multiple myeloma, elotuzumab takes this immune approach one step further. To label them for destruction, daratumumab targets the CD38 receptor, which is highly expressed on myeloma cells. But elotuzumab is an antibody that targets the SLAMF7 receptor, which is present on both myeloma cells and natural killer (NK) cells. This enhances the immune response through multiple mechanisms: by attaching to the myeloma cells, it marks them for destruction, and by attaching to the NK cells, it primes the immune cells to search for and attack the myeloma cells.
Prior to this trial, elotuzumab had already received priority review, as well as orphan drug and breakthrough therapy designation, from the FDA. It is also currently under review by the European Medicines Agency, which granted it accelerated assessment. Empliciti™ is marketed by Bristol-Myers Squibb, while Darzalex® is marketed by Janssen Biotech.