Karyopharm Seeks Accelerated FDA Approval for XPOVIO in Myelofibrosis

What Happened

• On August 31, 2026, Karyopharm Therapeutics announced it submitted a supplemental New Drug Application (sNDA) to the FDA seeking Accelerated Approval of XPOVIO® (selinexor) in combination with ruxolitinib for patients with myelofibrosis.
• The company requested Priority Review (which, if granted, would generally target a six‑month review). Karyopharm expects notice of the FDA’s decision on filing acceptance and anticipated review timelines in Q4 2026 after the FDA’s 60‑day filing review period.
• The sNDA is based in part on topline results from the Phase 3 SENTRY trial, which Karyopharm says shows a promising overall survival signal and supports a positive benefit‑risk profile for the combination.

Key Details

• Filing date announced: August 31, 2026.
• Regulatory expectation: FDA 60‑day filing review; company expects filing‑acceptance notice and timelines in Q4 2026.
• Requested review status: Priority Review (six‑month target if granted).
• Approval pathway note: Karyopharm expects Accelerated Approval would require FDA agreement that spleen volume reduction ≥35% (SVR35) is a reasonably likely surrogate for overall survival; long‑term overall survival data from SENTRY would be used to verify benefit and support conversion to traditional approval.

Why It Matters

• This filing starts the formal regulatory review process for expanding XPOVIO’s use into myelofibrosis in combination with ruxolitinib; a Priority Review could accelerate the FDA decision timeline.
• If the FDA accepts Accelerated Approval based on SVR35 as a surrogate, Karyopharm would need to confirm benefit with long‑term overall survival data from the Phase 3 SENTRY trial to maintain traditional approval.
• The company’s announcement includes standard forward‑looking statements and identifies risks (including those in its Q2 2026 10‑Q), so investors should note filing acceptance, FDA review decisions, and confirmatory data timing as key upcoming milestones.