J&J Bispecific Duo Cuts PSA 50%+ in 73% of Prostate Cancer Patients
New Brunswick, N.J. – November 08, 2026 -- Johnson & Johnson reported that 73% of patients (11 of 15) treated with its pasritamig and JNJ-9401 bispecific antibody combination achieved PSA reductions of at least 50% in a first-in-human Phase 1 study in metastatic castration-resistant prostate cancer (mCRPC). Seven of the 15 patients (47%) reached reductions of at least 90%. The data were presented in a late-breaking oral session at the Society for Immunotherapy of Cancer (SITC) 2026 Annual Meeting (Abstract #1175).
Dual-antigen regimen targets KLK2 and PSMA with complementary T-cell signals
The combination is the first dual-tumor-antigen-targeted bispecific regimen clinically evaluated in prostate cancer. Pasritamig, a first-in-class KLK2xCD3 bispecific, directs T cells toward prostate cancer cells. JNJ-9401, a PSMAxCD28 costimulatory bispecific, adds a second signal meant to strengthen and sustain T-cell activity.