Selinexor's myelofibrosis sNDA filed with strong Phase 3 data, but forbearance expires Oct 15 — survival past that date resolves everything

Karyopharm is a clinical-stage biopharmaceutical company developing selinexor in combination with an existing drug to treat myelofibrosis, a blood disorder; the combination is not yet approved, though the company has filed for regulatory review based on Phase 3 trial data.

Karyopharm filed a myelofibrosis sNDA for selinexor plus ruxolitinib on Phase 3 SENTRY data that met its SVR35 endpoint, with FDA confirming SVR35 as a reasonably likely surrogate — but the company defaulted on a $15.8M debt payment and has cash only through October 15, 2026. Whether the thesis survives depends entirely on a strategic transaction or capital raise materializing before forbearance expires, as no approval decision will precede that deadline. The sNDA itself carries approval-path risk, as accelerated approval on a surrogate endpoint in myelofibrosis remains unproven regulatory territory.