Johnson & Johnson Reports 75% Tumor Response Rate for JNJ-6143 in Advanced Prostate Cancer

04:50 AM EDT, 10/26/2026 (MT Newswires) -- Johnson & Johnson's (JNJ) investigational advanced prostate cancer drug JNJ-6143 showed a 75% complete or partial tumor response rate among patients who had received multiple prior treatments in a phase 1 trial, the company said Monday. In the 50 mg dose cohort, 77% of the 38 patients in the ongoing study achieved a confirmed reduction in prostate-specific antigen levels of at least 50%, and 48% had reductions of at least 90%, the company said. Patients had received a median of four previous treatments. At the analysis, 71% of those taking the 50-mg dose remained on treatment after a median follow-up of 5.6 months, Johnson & Johnson said. The company said the most common treatment-related side effects were elevated cholesterol, nausea and elevated triglycerides, and most treatment-related adverse events were mild to moderate. The evidence supports continued development of the drug, including a Phase 2 study, the company said.