Daratumumab monotherapy demonstrated promising efficacy and a manageable safety profile in heavily pretreated patients with multiple myeloma in a pooled, post-hoc analysis of the GEN501 and SIRIUS studies. The combined analysis included 148 patients with a median of five prior treatment lines, 87% of whom were double refractory. With a median follow-up of 36.6 months, the overall response rate was 30.4%, including 14% achieving a very good partial response or better and 5% achieving a complete response. Among the 45 responders, the median duration of response was 8.0 months, and the median overall survival was 20.5 months, with a 3-year survival rate of 36.5%.

The treatment was generally well-tolerated, with common grade 3 to 4 treatment-emergent adverse events including anemia (18%) and thrombocytopenia (14%). Serious drug-related adverse events occurred in 9% of patients, but no treatment-related deaths were reported. These findings confirm the durable responses and safety of daratumumab monotherapy, supporting its role as a valuable treatment option for patients with heavily pretreated multiple myeloma.

Reference: Usmani SZ, Nahi H, Plesner T, et al. Daratumumab monotherapy in patients with heavily pretreated relapsed or refractory multiple myeloma: final results from the phase 2 GEN501 and SIRIUS trials. Lancet Haematol. 2020;7(6):e447-e455. doi: 10.1016/S2352-3026(20)30081-8.