The Investor
09 Nov 2026, 19:15
Johnson & Johnson Reports 73% PSA Response With Experimental Prostate Cancer Combination
Johnson & Johnson (NYSE: JNJ) reported encouraging Phase 1 results for an experimental prostate cancer immunotherapy combination, with 73% of patients at the recommended regimen achieving at least a 50% reduction in prostate-specific antigen.
The regimen combines pasritamig, a KLK2-targeting bispecific antibody, with JNJ-9401, a PSMA-targeting bispecific designed to provide a complementary T-cell activation signal. Among 15 patients treated at the recommended dose, 11 achieved PSA reductions of at least 50%, while seven, or 47%, achieved reductions of at least 90%.
The responses also appeared durable in this early dataset. All seven patients with PSA reductions of at least 90% remained on treatment for more than six months without disease progression. Four patients achieved undetectable PSA levels.
Safety was also encouraging at the recommended regimen. No Grade 3 or higher treatment-related adverse events, dose-limiting toxicities, treatment-related discontinuations or deaths were reported. Cytokine release syndrome occurred in three patients, but all cases were mild Grade 1 events.
The combination is now being evaluated in the Phase 3 KLK2-comPAS study in metastatic castration-resistant prostate cancer, representing an important next step for Johnson & Johnson’s prostate cancer pipeline.
While the Phase 1 results are based on a small patient group and require confirmation in larger studies, the depth of PSA responses and early safety profile suggest the dual-targeted approach could become a meaningful new option in advanced prostate cancer.
Johnson & Johnson (NYSE: JNJ) reported encouraging Phase 1 results for an experimental prostate cancer immunotherapy combination, with 73% of patients at the recommended regimen achieving at least a 50% reduction in prostate-specific antigen.
The regimen combines pasritamig, a KLK2-targeting bispecific antibody, with JNJ-9401, a PSMA-targeting bispecific designed to provide a complementary T-cell activation signal. Among 15 patients treated at the recommended dose, 11 achieved PSA reductions of at least 50%, while seven, or 47%, achieved reductions of at least 90%.
The responses also appeared durable in this early dataset. All seven patients with PSA reductions of at least 90% remained on treatment for more than six months without disease progression. Four patients achieved undetectable PSA levels.
Safety was also encouraging at the recommended regimen. No Grade 3 or higher treatment-related adverse events, dose-limiting toxicities, treatment-related discontinuations or deaths were reported. Cytokine release syndrome occurred in three patients, but all cases were mild Grade 1 events.
The combination is now being evaluated in the Phase 3 KLK2-comPAS study in metastatic castration-resistant prostate cancer, representing an important next step for Johnson & Johnson’s prostate cancer pipeline.
While the Phase 1 results are based on a small patient group and require confirmation in larger studies, the depth of PSA responses and early safety profile suggest the dual-targeted approach could become a meaningful new option in advanced prostate cancer.
