A peptide just carried radiation straight into cancer cells and won a phase 3 trial
phase 3, in people with neuroendocrine tumors
It mimics a hormone the tumor is covered in receptors for, so the radiation goes where the peptide goes.
What happened
Bristol Myers Squibb says RYZ101, a radioactive peptide from its RayzeBio unit, met the main goal of ACTION-1, a phase 3 trial in people with neuroendocrine tumors of the gut and pancreas (GEP-NETs).
Everyone in the trial had tumors that kept growing after lutetium-177 therapy, the radioligand doctors use today. At a planned interim analysis, people on RYZ101 went longer before their disease progressed than people on standard care, as judged by reviewers who didn't know who got what.
How it works
RYZ101 is built on DOTATATE, a small lab-made copy of somatostatin, a hormone these tumors carry receptors for in large numbers. Inject the peptide and it finds those receptors and sticks.
Bolted onto the peptide is actinium-225, an alpha emitter. Alpha particles travel only a few cell widths and hit hard, so the radiation goes where the peptide goes: into the tumor, with far less reaching the tissue around it.
Today's version puts lutetium-177 on the same kind of peptide. It gives off beta radiation, which travels further and hits softer. ACTION-1 tested the alpha version in people whose tumors kept growing on the beta version.
What it means for you
RYZ101 isn't a peptide anyone runs from a vial. It's hospital cancer medicine. But it's the clearest proof yet of what a peptide can do: read a receptor, ride straight to it, and deliver whatever it carries.
It's the same receptor logic behind the GLP-1 drugs: a peptide shaped to fit one lock in the body. In this case the lock sits on the tumor.
What's next
BMS hasn't released the numbers yet. It says the full results will be presented at a medical meeting, and overall survival is still being followed in the trial.
The numbers
- Phase 3 ACTION-1 (NCT05477576) met its primary endpoint at a planned interim analysis: longer progression-free survival than standard care, by blinded independent central review.
- Who: people with gastroenteropancreatic neuroendocrine tumors (GEP-NETs) that progressed after lutetium-177 radioligand therapy.
- Standard care in the trial: high-dose somatostatin analogs, everolimus or sunitinib.
- No median or hazard ratio has been released; BMS says the full results go to a medical meeting.
- Safety was consistent with the known profile; overall survival is still being followed.
The original: Bristol Myers Squibb (press release)
