RYZ101 meets progression-free survival endpoint in Phase 3 ACTION-1 trial for GEP-NETs

What's the deal? On 12 October 2026, Bristol Myers Squibb reported that the interim analysis of the Phase 3 ACTION-1 trial of RYZ101 met its primary endpoint: a statistically significant and clinically meaningful improvement in progression-free survival (the time patients live without their disease worsening) compared with standard of care in patients with gastroenteropancreatic neuroendocrine tumours (GEP-NETs), a rare type of cancer that arises in hormone-producing cells of the digestive system. RYZ101 is being developed by RayzeBio, which BMS acquired in 2024. The FDA granted RYZ101 Orphan Drug Designation for GEP-NETs in August 2026, and the company plans to discuss next steps toward a regulatory submission with the FDA. Detailed results are expected at a future medical meeting.

Why it matters: RYZ101 is a radiopharmaceutical therapy in which a radioactive isotope (actinium-225) is attached to a molecule that homes in on cancer cells, delivering targeted radiation. These are the first Phase 3 results for an alpha-particle-based targeted radiotherapy in any indication. Standard treatment for GEP-NETs that have progressed after a first line of therapy has limited options, so a drug that meaningfully extends the time before progression — if confirmed in the full dataset — could become a new standard for patients whose disease has returned or stopped responding to prior treatment.

Read more: Bristol Myers Squibb, 12 October 2026 · BioSpace, 12 October 2026