Aiming alpha radiation at prostate cancer - one PSMA-tagged antibody at a time.
A vial of actinium-225 has a roughly ten-day half-life, which means the moment it leaves the cyclotron, it is already disappearing. Convergent Therapeutics has built a company around that urgency. Inside its labs at 1 Broadway, a team of about three dozen people races the decay clock to attach the most powerful radiation in clinical oncology to an antibody that knows exactly where to go.
This is not a company with a product on pharmacy shelves. It is a clinical-stage biotech, which is a polite way of saying it has spent more money than it has made and is betting the difference on data. In June 2026 it stood on stage at ASCO - the largest cancer meeting on earth - and presented what it called the biggest prospective Phase 2 dataset for an alpha radiopharmaceutical in patients who had already exhausted the standard PSMA option. The room, full of people paid to be skeptical, took notes.
Metastatic castration-resistant prostate cancer is the version of the disease that no longer responds to hormone therapy. For a stretch of patients, a radioligand called Lu-PSMA (Novartis markets it as Pluvicto) buys time. Then it, too, stops working. What comes next has been a thin menu.
The radiation itself is part of the puzzle. Lutetium-177 is a beta emitter: its particles travel relatively far and scatter energy across a wide path, which is gentler but less surgical. Alpha emitters like actinium-225 hit harder and travel only a few cell diameters - a couple of human hairs' width - before they stop. Enormous destructive power, almost no range. The trick has always been steering it.
A protein that sits on the surface of prostate cancer cells in abundance. Hit it, and you've found the tumor.
An alpha emitter with a ~10-day half-life. Lethal up close, harmless a hair's width away.
Salivary glands and kidneys are the usual casualties of PSMA therapy. Dry mouth and renal damage are the price.
Convergent's wager rests on a discovery older than the company. Dr. Neil Bander, the Bernard & Josephine Chaus Professor of Urologic Oncology at Weill Cornell Medicine, was among the first scientists to validate PSMA as a target in prostate cancer. The antibody platform built in his lab was licensed from Cornell University - the seed the company grew from.
The other half of the bet is Dr. Philip Kantoff, a medical oncologist with a resume that reads like a tour of American cancer medicine: former chair of the Department of Medicine at Memorial Sloan Kettering, former chief of solid tumor oncology at Dana-Farber, an endowed chair emeritus at Harvard. He joined as CEO in 2021. Bander provides the science; Kantoff provides the clinical and operational gravity. They co-founded Convergent in 2020.
Medical oncologist; former Chair of Medicine at Memorial Sloan Kettering and Chief of Solid Tumor Oncology at Dana-Farber.
Weill Cornell urologic oncologist who helped validate PSMA as a cancer target; inventor of the licensed platform.
Leads clinical development of the CONVERGE-01 program.
The lead candidate - formally Ac-225 rosopatamab tetraxetan, mercifully shortened to CONV01-α - is a monoclonal antibody that binds PSMA, carrying actinium-225 as its warhead. The antibody handles the navigation. The isotope handles the demolition.
The design intent is delivery, not just destruction: route the alpha radiation onto malignant cells while sparing the kidneys and salivary glands that usually pay the toll. An antibody is a larger, slower vehicle than a small-molecule ligand, and the bet is that this changes where the radiation ends up - and, critically, where it doesn't.
PSMA-targeted radioantibody · actinium-225 payload · Phase 2 (CONVERGE-01) in Lu-PSMA-exposed mCRPC.
Licensed from Cornell, extendable beyond prostate cancer to other solid tumors.
Kantoff and Bander launch Convergent around technology licensed from Cornell University.
The veteran oncologist takes the operational reins.
Supply agreements signed with IONETIX and NorthStar Medical Radioisotopes for Ac-225.
Led by OrbiMed and RA Capital Management, with Invus participating.
FDA clears the CONV01-α IND; the first patient is treated in the Phase 2 CONVERGE-01 trial. Cardinal Health begins Ac-225 shipments.
Largest prospective Phase 2 alpha-radiopharmaceutical dataset in Lu-PSMA-exposed mCRPC; Phase 3 in planning.
Convergent's Phase 2 CONVERGE-01 trial enrolled patients who had already been through Lu-PSMA - exactly the group with the fewest options. The interim Part 3 results reported anti-tumor activity, emerging durability, and a tolerability profile the company described as highly favorable. The headline, though, was about what didn't happen.
Nearly half the patients - 48% - walked into the trial already living with xerostomia, the dry mouth that PSMA therapies are notorious for. After treatment with CONV01-α, no high-grade xerostomia was observed, and 77% of patients landed at the mildest grades. No renal toxicity was reported. For a therapy whose entire premise is "hit harder without hitting the wrong things," that is the proof point that matters.
Behind the clinic sits an unglamorous but decisive achievement: supply. Actinium-225 is famously scarce, and a therapy is worthless if you cannot source its active ingredient. Convergent signed agreements with IONETIX and NorthStar in 2022, then began receiving non-carrier-added Ac-225 from Cardinal Health to feed the trial. Plenty of promising radiopharmaceuticals have stalled not on biology but on logistics.
Convergent's stated mission - unlocking the full potential of alpha radioantibodies - sounds like the kind of line every biotech keeps on a slide. What makes it specific here is the word "antibody." The company's whole thesis is that pairing the most localized radiation in medicine with a targeting molecule that actually finds the tumor is the difference between a blunt instrument and a precise one.
The platform was built on prostate cancer because that is where PSMA lives and where Bander's science began. But the architecture - targeting molecule plus alpha payload - is not married to a single disease. Convergent describes its ambitions as extending to other solid tumors, which is the polite version of saying: if this works, it is a method, not a medicine.
Convergent's stated next step is a pivotal Phase 3 trial in patients who have been through both taxane chemotherapy and Lu-PSMA - the population running lowest on options and highest on need. A Phase 3 is where promising data either becomes a medicine or becomes a cautionary tale. The company is not there yet, and it would be dishonest to pretend the outcome is decided.
But return to that vial of actinium-225, arriving in Cambridge with its half-life already running down. A few years ago, the most useful thing anyone could do with it was study it. Now there is a building full of people who can attach it to an antibody, route it to a tumor, and - by their own Phase 2 evidence - leave the salivary glands and kidneys largely alone. The clock still ticks. The difference is that Convergent has figured out where the radiation should be when it stops.