Karyopharm Achieves Phase 3 SENTRY Primary Endpoint for Selinexor-Ruxolitinib Combination in Myelofibrosis

With a statistically significant near-doubling of SVR35 response rates and an early overall survival signal, Karyopharm Therapeutics has moved the selinexor-ruxolitinib combination measurably closer to a regulatory submission, and manufacturing teams will need to begin readiness planning now. Results from the Phase 3 SENTRY trial were presented as a late-breaking oral at the 2026 ASCO Annual Meeting on June 2 and simultaneously published in the Journal of Clinical Oncology.

The co-primary endpoint data are unambiguous: SVR35 at week 24 was achieved in 49.8% of patients on the selinexor combination versus 28.0% on ruxolitinib alone (odds ratio 2.58; 95% CI 1.60–4.17; p<0.0001). Responses were durable, with SVR35 rates of 49.4% versus 20.3% at week 12 and 46.9% versus 23.0% at week 36. Across prespecified subgroups, the benefit was consistent, including in patients receiving less than 15 mg ruxolitinib per day, a finding with direct implications for dose-flexibility in a commercial formulation strategy.

For QA and regulatory leads, the overall survival signal adds weight to the filing case: Kaplan-Meier curves showed early and sustained separation between arms, with a greater than 50% reduction in risk of death versus ruxolitinib alone. Evidence of potential disease modification, more patients achieving 20% or greater reductions in variant allele frequency (VAF) as early as week 24, may support a broader label claim, though that determination rests with FDA review under the applicable NDA or sNDA pathway.

On the symptom side, absolute Total Symptom Score reductions were comparable across arms (mean reduction of 9.9 points for the combination), indicating the efficacy gain in spleen response does not come at the cost of symptom burden, a profile that simplifies the benefit-risk narrative in a 21 CFR Part 314 submission package. The median selinexor dose of 51.7 mg/week and median ruxolitinib dose of 23.0 mg/day establish the reference dosing parameters that process validation and drug product manufacturing teams will need to anchor combination-product planning.

For plant heads and supply-chain leads, a combination regimen involving two distinct active pharmaceutical ingredients, one already commercially manufactured (ruxolitinib, Incyte) and one in Karyopharm's existing commercial network (selinexor, approved as Xpovio), raises co-packaging, labeling, and ICH Q10 pharmaceutical quality system alignment questions that are best addressed before an NDA submission is filed, not after.

The pace at which Karyopharm moves from SENTRY data to a regulatory submission will set the clock on when manufacturing readiness reviews, process validation protocols, and any required comparability studies must be completed.

Source: Karyopharm Therapeutics Investor Relations via PR Newswire, June 2, 2026; ASCO 2026 late-breaking oral presentation LBA6500, simultaneous publication in the Journal of Clinical Oncology.