Daratumumab monotherapy had a favorable safety profile and encouraging efficacy in patients with heavily pretreated and refractory multiple myeloma, a new study published online ahead of print in The New England Journal of Medicine has shown.1
Because CD38 is strongly overexpressed in multiple myeloma cells, researchers evaluated the safety and efficacy of daratumumab, a CD38-targeting, human IgG1k monoclonal antibody, in patients with relapsed multiple myeloma or relapsed myeloma that was refractory to 2 or more prior lines of treatment.
For the phase 1/2 study, researchers enrolled a total of 72 patients into the dose-expansion phase. Of those, 64% had disease refractory to bortezomib and lenalidomide.
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Thirty patients received daratumumab 8 mg/kg and 42 received the immunotherapy at a dose of 16 mg/kg once weekly for 8 doses, twice monthly for 8 doses, and then monthly for up to 24 months.
Efficacy results showed that the overall response rate was 36% and 10% in the 16 mg/kg group and 8 mg/kg group, respectively.
Researchers found that median progression-free survival was 5.6 months (95% CI: 4.2, 8.1) in the 16 mg/kg cohort, and 65% of those who achieved a response in that group did not have not disease progression at 12 months.
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In regard to safety, 71% of patients experienced any grade infusion-related reactions and 1% had a grade 3 infusion-related reaction. None were related to the dose. The most frequent grade 3 or 4 adverse events were pneumonia and thrombocytopenia.
Preliminary findings of a phase 2 trial presented at the 2015 ASCO Annual Meeting also demonstrated meaningful durable activity with daratumumab monotherapy at a dose of 16 mg/kg in patients with at least 3 lines of prior therapy or double refractory multiple myeloma.
Reference
- Lokhorst HM, Plesner T, Laubach JP, et al. Targeting CD38 with daratumumab monotherapy in multiple myeloma [published online ahead of print August 26, 2015]. N Engl J Med. doi: 10.1056/NEJMoa1506348.
