PR Newswire·Nov 8, 2026, 11:00 AM ET

Johnson & Johnson reports 73% PSA response rate with investigational pasritamig-based immunotherapy combination in advanced prostate cancer

Johnson & Johnson announced first-in-human Phase 1 results for the dual-antigen-targeted bispecific regimen of pasritamig & JNJ-9401 targeting KLK2 & PSMA proteins in metastatic castration-resistant prostate cancer.
The combination utilizes complementary T-cell signals to activate immune cells against cancer, representing the first clinically evaluated dual-tumor-antigen-targeted bispecific antibody regimen in this disease.
In the Phase 1 study, 73% (11 of 15 patients) achieved PSA reductions of at least 50%, while 47% (7 of 15 patients) achieved reductions of at least 90%.
All seven patients with PSA reductions of at least 90% remained on treatment for more than six months without disease progression.
No Grade 3 or higher treatment-related adverse events were reported, & no cases of immune effector cell-associated neurotoxicity syndrome were observed.
Cytokine release syndrome occurred in three patients (20%) but was mild (Grade 1), presenting as temporary fever without requiring tocilizumab treatment.
The recommended regimen involves JNJ-9401 200 mg subcutaneously & pasritamig 300 mg intravenously, both administered every six weeks following initial weekly pasritamig step-up doses.
The dosing schedule suggests potential for outpatient administration as the combination advances to Phase 3.
The Phase 3 KLK2-comPAS study (NCT07164443) is now evaluating whether adding JNJ-9401 to pasritamig improves outcomes for patients with mCRPC.