Ac-225 Rosopatamab Tetraxetan (CONV01-α): CONVERGE-01 Interim Data Show Encouraging Activity After Lu-177-PSMA Therapy


Ac-225 rosopatamab tetraxetan shows promising activity in Lu-PSMA–pretreated mCRPC | Urology Times

Advanced Therapy Watch

Informed Prostate Cancer Support Group Newsletter — Advanced & Metastatic Disease Series

BLUF (Bottom Line Up Front): 

At the 2026 ASCO Annual Meeting, Convergent Therapeutics reported interim Phase 2 results from Part 3 of the CONVERGE-01 trial testing Ac-225 rosopatamab tetraxetan (CONV01-α), an alpha-particle-emitting radioantibody, in men with metastatic castration-resistant prostate cancer (mCRPC) whose disease had already progressed after Lu-177-PSMA radioligand therapy — a population with no established standard of care. Among 35 treated patients, 40% of those evaluable for PSA response achieved a decline of 50% or more, with the best durability seen at the intended Phase 3 target dose (median radiographic progression-free survival of 8.41 months). Side effects were mostly blood-count related and manageable; there was no kidney toxicity and no severe dry mouth. No patients stopped treatment because of side effects. The company plans to move CONV01-α into a pivotal Phase 3 trial for this Lu-PSMA-exposed population. CONVERGE-01 (NCT06549465) continues to enroll at UC San Diego and other U.S. sites; this is the same trial in which our IPCSG member Stephen Pendergast is currently participating.

Why This Matters

Lu-177-PSMA radioligand therapy (marketed as Pluvicto) has become a mainstay treatment for PSMA-positive mCRPC, but nearly all men eventually progress on it, and until now there has been no agreed-upon next step once that happens. CONV01-α approaches the same PSMA target with a different tool: instead of a small PSMA-binding molecule carrying a beta-emitting isotope (Lu-177), it uses a full-sized monoclonal antibody called rosopatamab, developed from research by Dr. Neil Bander at Weill Cornell Medicine, to carry the alpha-emitting isotope actinium-225 (Ac-225) directly into PSMA-expressing tumor cells. Alpha particles deposit far more energy over a much shorter path than beta particles, which in principle allows more precise cell killing with less collateral damage to nearby healthy tissue — including the salivary glands and kidneys, both of which can be affected by other PSMA-targeted radioligand therapies.

What Was Reported at ASCO 2026

The data were presented on June 1, 2026, by Dr. Michael J. Morris of Memorial Sloan Kettering Cancer Center, Scientific Advisory Committee Co-Chair for the trial, during ASCO's "Radiation Re-Imagined: Radioligand Innovation in Prostate Cancer" clinical science symposium in Chicago.

Patients and Trial Design

CONVERGE-01 is a Phase 2, open-label, multicenter study conducted in three parts. Part 1 characterized how the radioantibody distributes through the body and to tumor sites. Part 2 enrolled patients who had never received Lu-PSMA therapy, for dose optimization. Part 3 — the cohort reported at ASCO — enrolled patients who had already progressed on Lu-177-PSMA. All patients received CONV01-α as a fractionated two-dose regimen, on Day 1 and Day 15 of a single cycle.

CharacteristicPart 3 Cohort (n=35)
Median age72 years (range 58–83)
Median baseline PSA40.12 ng/mL (range 4.16–1,910)
Prior taxane chemotherapy80%
Prior ARPI therapy (e.g., abiraterone, enzalutamide, apalutamide, darolutamide)100%
Median prior Lu-177-PSMA cycles6 (range 2–6)
Median follow-up at analysis8.14 months

Efficacy

  • Among 25 patients evaluable for PSA response, 40% achieved a PSA decline of ≥50%, with responses seen across all dose groups tested (below, at, and above the intended target dose).
  • Durability was greatest at the dose selected for the planned Phase 3 trial (9 MBq/kg), where median radiographic progression-free survival reached 8.41 months (95% CI, 2.83 to not-yet-reached).
  • Dose escalation was completed without dose-limiting toxicities across the dose levels evaluated.

Safety

The most frequently reported treatment-related side effects were dry mouth (62.9%), nausea (60%), and reductions in lymphocyte and platelet counts (60% each), followed by fatigue (54.3%), anemia (40%), reduced appetite (40%), reduced white blood cell count (40%), reduced neutrophil count (34.3%), and altered taste (22.9%). Grade 3 (more severe) side effects were described as clinically manageable and generally temporary, and no patient discontinued treatment because of a side effect. Notably, there was no kidney toxicity and no severe (Grade 3+) dry mouth reported — an important distinguishing feature, since kidney effects and severe dry mouth have been concerns with some other PSMA-targeted radioligand approaches. Baseline dry mouth related to prior radioligand therapy was already present in 48.6% of enrolled patients before starting CONV01-α, rising modestly to 62.9% during treatment; Dr. Morris noted this uptick was somewhat unexpected, since imaging studies of the drug show minimal uptake in the salivary glands.

Reading the numbers with appropriate caution: These are interim results from a mid-sized, single-arm Phase 2 cohort (35 patients) with roughly eight months of median follow-up — not a randomized, controlled Phase 3 trial, and not yet FDA-reviewed data. A 40% PSA response rate and 8.4-month radiographic progression-free survival are encouraging signals in a group of heavily pretreated men who had already exhausted Lu-PSMA therapy, but they should be understood as early evidence of activity and tolerability, not a confirmed survival benefit. Longer follow-up and the planned randomized Phase 3 trial will be needed to establish that.

Regulatory and Corporate Background

Convergent Therapeutics, Inc. (Cambridge, Massachusetts) is a privately held, clinical-stage biotechnology company. The FDA cleared the company's Investigational New Drug (IND) application for CONV01-α in March 2024, clearing the way for Phase 2 testing. The underlying dual-targeting antibody-radioligand science originates from research by Dr. Neil Bander at Weill Cornell Medicine and is licensed to Convergent through patents held by Cornell University. Convergent has separately secured actinium-225 supply agreements with Cardinal Health and NorthStar Medical Radioisotopes to support clinical and eventual commercial manufacturing — a meaningful consideration given that Ac-225 has historically been in short, constrained global supply. The company's Series A extension, which included a $40 million investment from Novo Holdings, was announced in September 2024 alongside dosing of the first CONVERGE-01 patient. No court filings, litigation, or regulatory enforcement actions involving CONV01-α or CONVERGE-01 were identified as of this writing.

What Comes Next

Convergent Therapeutics has stated its intention to advance CONV01-α into a pivotal, randomized Phase 3 trial specifically for taxane- and Lu-PSMA-exposed patients — the population studied in Part 3 — citing the "increasing unmet patient need" in this group. CONVERGE-01 itself remains open and is continuing to enroll both Lu-PSMA-naïve and Lu-PSMA-pretreated patients at nine U.S. sites, including University of California San Diego, Duke Cancer Institute, and Memorial Sloan Kettering Cancer Center, among others. The study's estimated primary completion is December 2025, with overall study completion estimated for April 2027.

Disclaimer: This article is intended for patient education and general information purposes only. It is not medical advice and should not be used to make individual treatment decisions. Men considering or currently enrolled in CONVERGE-01 or any clinical trial should discuss their specific situation, lab results, and treatment options with their own oncology care team.

Sources

  1. Clarke, Hannah. "Ac-225 rosopatamab tetraxetan shows promising activity in Lu-PSMA–pretreated mCRPC." Urology Times, 2026. urologytimes.com
  2. Morris MJ, George DJ, Gupta S, et al. "CONVERGE-01 Part 3: Ac-225 rosopatamab tetraxetan (CONV01-α) in Lu-PSMA-pretreated metastatic castration-resistant prostate cancer (mCRPC)." Journal of Clinical Oncology 44, 2026 (suppl 16; abstr 5011). DOI: 10.1200/JCO.2026.44.16_suppl.5011
  3. "ASCO 2026: CONVERGE-01 Part 3: Ac-225 Rosopatamab Tetraxetan (CONV01-α) in 177Lu-PSMA-617 Pretreated mCRPC." UroToday, June 2026. urotoday.com
  4. "Convergent Therapeutics Announces Positive Phase 2 Data at ASCO 2026 Showing Promising Anti-Tumor Activity, Durability, and Favorable Tolerability for CONV01-α in Lu-PSMA-Exposed Metastatic Castration-Resistant Prostate Cancer (mCRPC)." Business Wire, June 1, 2026. businesswire.com
  5. "Convergent Therapeutics to Present Largest Set of Prospective Phase 2 Data for an Alpha Radiopharmaceutical in Lu-PSMA-Exposed Metastatic Castration-Resistant Prostate Cancer at ASCO 2026." Business Wire, May 21, 2026. businesswire.com
  6. "Convergent Therapeutics to Present Phase 2 Data for CONV01-α in Lu-PSMA pretreated Metastatic Castration-Resistant Prostate Cancer Patients at the 2026 ASCO Annual Meeting." Business Wire / FirstWord Pharma, April 21–22, 2026. firstwordpharma.com
  7. "Convergent Therapeutics Announces FDA Clearance of IND Application for CONV01-α, a Best-in-Class Radioantibody Targeting Prostate-Specific Membrane Antigen." PR Newswire, April 2, 2024. prnewswire.com
  8. "Convergent Therapeutics Announces First Patient Treated in Phase II Clinical Trial with Lead Therapeutic Candidate and Corporate Updates." BioSpace / PR Newswire, September 24, 2024. biospace.com
  9. "NorthStar Medical Radioisotopes and Convergent Therapeutics, Inc. Expand Strategic Collaboration Around CONV01-α." NorthStar Medical Radioisotopes / Business Wire, August 13–14, 2024. northstarnm.com
  10. "Convergent Therapeutics and Point Biopharma Announce a Collaboration to Evaluate CONV01-α (Rosopatamab-225Ac) in Combination with PNT2002 for Progressive Metastatic Castration-Resistant Prostate Cancer." PR Newswire, September 14, 2021. prnewswire.com
  11. ClinicalTrials.gov. "Study Evaluating Dosimetry, Randomized Dose Optimization, Dose Escalation and Efficacy of Ac-225 Rosopatamab Tetraxetan in Participants With PSMA PET-Positive Castration-Resistant Prostate Cancer (CRPC)" (CONVERGE-01), NCT06549465. Accessed June 2026. clinicaltrials.gov/study/NCT06549465
  12. Duke Cancer Institute. "CONVERGE-01 (Prostate Cancer)" trial listing. dukecancerinstitute.org
  13. Convergent Therapeutics, Inc. "Pipeline." convergentrx.com/pipeline

Prepared for the Informed Prostate Cancer Support Group newsletter. Article compiled from publicly available conference presentations, company press releases, and the ClinicalTrials.gov registry as of July 1, 2026.

 

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