Real-World Selinexor Response Shows Moderate Efficacy

Selinexor combinations had moderate efficacy in real-world patients with relapsed or refractory multiple myeloma (MM), according to a study presented at the 2022 American Society of Hematology Annual Meeting.

Efstathios Kastritis, MD, of National and Kapodistrian University of Athens in Greece, and colleagues conducted an analysis of 44 consecutive patients with relapsed or refractory disease treated with selinexor plus dexamethasone (Sd) or selinexor, bortezomib, and dexamethasone (SVd). Patients received a median of six prior lines of treatment.

In the intention-to-treat population, the overall response rate (ORR) was 29.5%, with an ORR of 35% for SVd and 24% for Sd. In patients with prior exposure to an anti-B-cell maturation antigen (BCMA) therapy, the ORR was 13%.

The median time to first response was one month. Median progression-free survival (PFS) was three months for all patients, and 6.9 months for those that responded to treatment. Median PFS was 2.7 months and 3.4 months for Sd and SVD, respectively.

The researchers conducted a univariate analysis and found that serum albumin <3.5 g/dL and lactate dehydrogenase (LDH) greater than the upper limit of normal (ULN) were both associated with inferior PFS. However, the number of prior lines of therapy and prior exposure to anti-BCMA treatment did not affect PFS outcomes.

The median overall survival (OS) was 13.7 months, which the researchers wrote sets a benchmark for the evaluation of new therapies. Median OS for those with a partial remission or better was 28 months. Again, serum albumin <3.5 g/dL and LDH greater than the ULN were associated with inferior OS.

More than half of patients treated with selinexor required a dose reduction. The researchers wrote that this likely indicates that the optimal dose of selinexor “may be lower than the recommended [dose].”

Common toxicities included infection (25%), thrombocytopenia (55%), fatigue (66%), nausea (47%), diarrhea (9%), hyponatremia (11%), and symptoms of confusion/altered mental state (18%).

Reference

Kastritis E, Malandrakis P, Spilopoulou V, et al. Real world efficacy and toxicity of selinexor: importance of dose intensity and post progression outcomes. Abstract #3181. Presented at the 64th American Society of Hematology Annual Meeting, December 10-13, 2022; New Orleans, Louisiana.