Regeneron registers prostate cancer bispecific trial; posts REGN5381 heart failure results

Four Regeneron programs saw activity this week, led by a newly registered prostate cancer trial and completed heart failure results.

• Regeneron registered a Phase 1/2 trial, "Phase 1/2 Trial of REGN21353 (a STEAP1xCD3 Bispecific Antibody) Administered Alone or in Combination With Nezastomig (a PSMAxCD28 Bispecific Antibody) in Participants With Metastatic Castration-Resistant Prostate Cancer (mCRPC)" (NCT07850921). The study is looking at the best dose of REGN21353 alone and together with nezastomig, side effects, how well it works, and pharmacokinetics in prostate cancer.¹ The trial is not yet recruiting, with a Phase 1/2 design and¹ an estimated enrollment of 192 participants and an estimated start date of 2027-06-28.
• Regeneron's Phase 2 trial of REGN5381, "REGN5381 in Heart Failure Adult Participants With Elevated Pulmonary Capillary Wedge Pressure" (NCT05353166), is completed with results first posted on 2026-09-29. The study tested REGN5381, an NPR1 agonist, in adult heart failure patients with a clinical indication for right heart catheterization,² enrolling 59 participants actual, with primary completion on 2025-06-02. The detailed description notes that Group A stopped enrolling and Group B will not enroll participants.²
• Regeneron's Phase 3 trial "ROXI-PEAK" (NCT07697599) is recruiting, testing REGN7508 and REGN9933 against placebo to see how well the drugs prevent blood clots compared to placebo after PICC placement and whether they cause certain types of bleeding,³ with an estimated enrollment of 1908 participants and an actual start date of 2026-09-07. The only listed site is in Georgia.
• Regeneron's Phase 1/2 glaucoma trial "REGN22530 for Adults With Primary Open Angle Glaucoma or Ocular Hypertension" (NCT07675824, acronym BAHAMA) remains recruiting, with its single site at Advanced Research in Deerfield Beach, Florida, per the last update posted on 2026-09-28.