Karyopharm to present new data on SDd, SPd arm in Phase 1b/2 STOMP study
Karyopharm Therapeutics announced three presentations highlighting new and updated data from the Phase 1b/2 STOMP study evaluating selinexor, the company's first-in-class, oral Selective Inhibitor of Nuclear Export compound, and dexamethasone in combination with standard approved multiple myeloma therapies, Kyprolis Darzalex, or Pomalyst, in patients with previously treated multiple myeloma. Updates on Phase 1b/2 STOMP Study: SDd and SPd The data will be featured in oral and poster presentations at the European Hematology Association 2019 Annual Meeting. In this arm of the Phase 1b/2 STOMP study, oral selinexor is being evaluated in combination with Darzalex in patients with relapsed or refractory MM who received at least three prior lines of therapy, including a PI and an IMiD, or patients with MM refractory to both a PI and an IMiD. Despite the heavily pretreated nature of the patients in the study, with 100% of the patients having dual--refractory disease, only one patient did not have at least a minimal response. Median progression-free survival has not been reached. Among patients with at least a PR, the median time on treatment was 7.7 months, while the median time on study for all evaluable patients was 4.8 months. Median time to response was 1.0 month. Based on published data, the expected ORR for Darzalex therapy without selinexor in the Darzalex-naive population is ~29%. Thus, the ORR of 73% continues to provide a basis for further evaluation of the SDd combination. Among the 31 patients evaluated for safety as of the data cutoff date, the most common treatment-related AEs were cytopenias, along with gastrointestinal and constitutional symptoms; most manageable with dose modifications and/or standard supportive care. The most common non-hematologic treatment-related AEs were nausea, fatigue, anorexia, insomnia, diarrhea, hyponatremia, and vomiting, and were mostly Grade 1 and 2 events. As expected, the most common Grade 3 and 4 treatment-related AEs were hematologic AEs and included thrombocytopenia, anemia, leukopenia and neutropenia. No Grade 5 AEs were reported. Based on these tolerability and efficacy data, the recommended RP2D of SDd is selinexor, Darzalex and dex.