Elotuzumab, a humanized IgG1 monoclonal antibody, led to very high response rates and prolonged remissions in 73 patients with relapsed multiple myeloma or refractory to previous treatment in a phase 2 study presented by Sagar Lonial, MD, of Emory University School of Medicine, Atlanta.
Patients who received elotuzumab (10 or 20 mg/kg) in combination with lenalidomide and low-dose dexamethasone had an 82% overall response rate. Response rates exceeded 90% in patients who had received 1 previous therapy and those who received the lower dose.
“We see an 80% to 90% response rate, and at 14 months, we have not yet hit median PFS [progression-free survival],” said Dr Lonial. The PFS rate has ranged from 65% to 75%.
The drug was well tolerated. With prophylaxis, only 1 grade 3 infusion reaction was documented. Some 12% of patients had complete responses and 36% had very good partial responses. “These were durable responses. Over half the patients are still on study,” he noted.
In a subset analysis, the combination showed encouraging activity—80% response rate—in cytogenetically high-risk patients. “If we can use a drug to overcome high-risk disease, this would be great,” Dr Lonial commented.
Phase 3 trials of 10 mg/kg of elotuzumab are ongoing in previously untreated patients and in those with relapsed/refractory disease.
Sonja Zweegman, MD, PhD, VU University Medical Center, Amsterdam, and Erasmus University, Rotterdam, the Netherlands, who moderated a session on new agents in myeloma, commented that the use of monoclonal antibodies is a true advance in myeloma. “We eagerly await monoclonal antibody-based therapy in myeloma. These agents attack the plasma cell in a different way, and they will certainly be additive to our arsenal.
Encouragingly, what we saw at ASH is that all these new investigational compounds are not only effective, but tolerable. I think elotuzumab has a lot of potential,” Dr Zweegman concluded.—CH