Karyopharm Achieves Full Enrollment in Phase 3 Endometrial Cancer Trial with Topline Data Due Mid-2026

Karyopharm Therapeutics has completed enrollment in its Phase 3 XPORT-EC-042 trial, setting up a mid-2026 topline readout that could trigger an sNDA submission for selinexor in endometrial cancer and force manufacturing and regulatory teams to begin scale-up planning now. For plant heads and QA directors already managing XPOVIO's existing commercial supply, a positive readout compresses the timeline between clinical data and process validation requirements.

The enrollment completion lands alongside a separate Phase 3 signal in myelofibrosis. Topline results from the SENTRY trial, a randomized, double-blind study evaluating 60 mg selinexor combined with ruxolitinib versus ruxolitinib alone in 353 frontline myelofibrosis patients, met the first co-primary endpoint of spleen volume reduction of 35% or more (SVR35) at week 24, with sustained benefit observed over time. The trial did not meet its second co-primary endpoint of mean change in absolute total symptom score at week 24. A promising overall survival signal was observed, which Karyopharm has indicated reinforces the clinical rationale for XPO1 inhibition in this setting. SENTRY results are selected for a late-breaking oral presentation at the 2026 ASCO Annual Meeting on June 2.

On the commercial side, U.S. XPOVIO net product revenue reached $29.2 million in Q1 2026, up from $21.1 million in Q1 2025, though demand softened relative to the prior-year quarter due to new competitive entrants. The community setting accounted for approximately 60% of net product revenue. Royalty revenue from international partners Menarini, Antengene, and others rose to $1.9 million from $1.7 million year-over-year, with selinexor now approved in more than 50 ex-U.S. countries and territories, a footprint that adds complexity to any label-expansion supply strategy.

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 regulatory affairs leads, the convergence of two Phase 3 programs approaching decision points within the same calendar year warrants early engagement on submission-readiness, including CMC documentation alignment under 21 CFR Part 211 and ICH Q10 quality system requirements.

The mid-2026 XPORT-EC-042 topline readout will be the next measurable checkpoint for teams assessing whether an sNDA filing timeline is viable within the current fiscal year.

Source: Karyopharm Therapeutics Investor Relations via PRNewswire, 2026-05-14. Conference call held 8:00 a.m. ET same day.