Can a Peptide Target Cancer? RYZ101 and the ACTION-1 Study
RYZ101 · GEP-NETs; investigational, not FDA approved · Status checked 2026-10-14
A peptide guides an investigational radioactive therapy to tumor receptors. What the phase 3 ACTION-1 announcement shows—and what remains unanswered.
By Pacific RX editorial team · Published
At a glance
RYZ101 links DOTATATE, a peptide that targets somatostatin receptors, to the radioactive isotope actinium-225. Its alpha radiation can damage DNA in cancer cells. The peptide provides targeting; the radioactive payload supplies the cell-damaging mechanism.
A targeting peptide carries radiation to cancer cells
RYZ101 links DOTATATE, a peptide that targets somatostatin receptors, to the radioactive isotope actinium-225. Its alpha radiation can damage DNA in cancer cells. The peptide provides targeting; the radioactive payload supplies the cell-damaging mechanism.
This specialized radiopharmaceutical approach does not establish that BPC-157, TB-500 or other general peptide protocols kill cancer. It is investigational oncology treatment, not a Pacific RX cancer-care offering.
What ACTION-1 reported
On October 12, 2026, Bristol Myers Squibb and RayzeBio announced that a planned interim analysis of randomized phase 3 ACTION-1 met its progression-free-survival endpoint. The study compares RYZ101 with investigator-selected standard care in somatostatin receptor-positive gastroenteropancreatic neuroendocrine tumors after progression on lutetium-177-based treatment.
The announcement reports a statistically significant, clinically meaningful improvement, but does not provide numerical effect estimates or detailed safety results. It is sponsor-reported topline evidence; detailed results are expected at a future medical meeting. Progression-free survival measures time before disease progression or death and does not establish cure. Participants continue to be followed for overall survival.
Where it sits in the regulatory journey
As reviewed October 14, 2026, RYZ101 is in phase 3 development and remains investigational. The sponsor reports FDA orphan drug designation in August 2026 for GEP-NETs and plans discussions with the FDA about next steps toward a regulatory submission.
Orphan drug designation supports development for a rare condition; it is not marketing approval. A positive interim result does not mean an application has been submitted, accepted for review or approved. The stage tag therefore remains Phase 3 · investigational.