Karyopharm Files Selinexor sNDA in August Under Accelerated Approval for Myelofibrosis Combination

An August sNDA submission for selinexor plus ruxolitinib keeps Karyopharm Therapeutics on a regulatory trajectory that, if successful, would place the first approved combination therapy for myelofibrosis into commercial channels. The filing proceeds under the Accelerated Approval pathway, with a Priority Review designation request planned at the time of submission.

The regulatory basis is substantive. Following Type B and Type C meetings, FDA provided written feedback confirming that spleen volume reduction of 35% or greater (SVR35) qualifies as a reasonably likely surrogate endpoint to predict overall survival, satisfying the evidentiary threshold for an Accelerated Approval submission. That written confirmation materially de-risks the filing strategy and narrows the agency's interpretive latitude at the review stage.

Supporting clinical data come from the Phase 3 SENTRY trial (NCT04562389), results from which were presented in a Late-Breaking Oral session at the 2026 American Society of Clinical Oncology meeting and at the European Hematology Association congress, and subsequently published in the Journal of Clinical Oncology. Peer-reviewed publication alongside major congress presentations strengthens the evidentiary package regulatory reviewers will assess.

On the commercial side, U.S. XPOVIO net product revenue reached $30.8 million for Q2 2026, up from $29.7 million in Q2 2025, with the community setting accounting for approximately 60% of net product revenue. Royalty revenue from international partners Menarini and Antengene grew to $2.5 million from $1.6 million year-over-year, reflecting selinexor's approval in more than 50 ex-U.S. countries and territories. Total Q2 revenue was $33.4 million.

Karyopharm reaffirmed full-year 2026 total revenue guidance of $130 million to $150 million, with U.S. XPOVIO net product revenue guidance of $115 million to $130 million. For QA and regulatory leads tracking the submission timeline, the Priority Review request, if granted, would compress the standard review clock to six months from acceptance, concentrating CMC and labeling alignment activity into a tighter window than a standard review would allow.

The FDA's acceptance decision and any Priority Review designation will be the next measurable checkpoint against which the August submission timeline can be evaluated.

Source: Karyopharm Therapeutics Investor Relations via PRNewswire, 2026-08-13. Conference call held 8:00 a.m. ET same day.