Johnson & Johnson prostate cancer drug JNJ-6143 shows tumor shrinkage in early-stage trial

At the 2026 ESMO Congress, Johnson & Johnson reported promising early-stage clinical trial results for its experimental prostate cancer drug JNJ-6143, acquired via its $3.05 billion purchase of Halda Therapeutics in 2025. Among 31 patients on a 50-mg dose, 77% achieved at least a 50% drop in PSA levels, and 69% showed tumor shrinkage. Separately, a UCL study demonstrated that the Decipher genomic test can identify high-risk patients who would benefit most from abiraterone hormone therapy.

Early-stage trial results for JNJ-6143

• ▪Common side effects in the JNJ-6143 trial were nausea, elevated cholesterol, and elevated triglyceride levels, leading one patient to discontinue treatment due to adverse effects.
• ▪Early-stage trial results for JNJ-6143 were presented at the 2026 European Society for Medical Oncology Congress in Madrid.
• ▪In an early-stage trial of Johnson & Johnson's experimental prostate cancer drug JNJ-6143, prostate-specific antigen levels fell by at least 50% in 77% of 31 evaluable patients receiving a 50-milligram dose, and by at least 90% in 48%.
• ▪Among trial patients with measurable tumors, 69% achieved a confirmed complete or partial response following treatment with JNJ-6143.

JNJ-6143 mechanism and trial population

• ▪Johnson & Johnson evaluated the experimental prostate cancer drug JNJ-6143 in patients with advanced disease who had previously received multiple treatments.
• ▪The experimental once-daily oral drug JNJ-6143 selectively kills cancer cells by interfering with a protein necessary for their survival.

Johnson & Johnson acquisition of JNJ-6143

• ▪A Johnson & Johnson spokesperson stated that JNJ-6143 adds a new mechanism of action to the company's existing prostate cancer portfolio.
• ▪Johnson & Johnson gained access to the experimental prostate cancer drug JNJ-6143 through its $3.05 billion acquisition of Halda Therapeutics in 2025.

Decipher test for prostate cancer

• ▪University College London researchers found Decipher scores predicted which patients whose cancer had not yet spread to lymph nodes would benefit from abiraterone therapy.
• ▪Dr. Sarah Howlett of the UCL Cancer Institute noted that genomic testing could spare men with low Decipher scores from intensive treatments while prioritizing high-score men for them.
• ▪A University College London study analyzing Decipher scores for over 6,000 men found higher scores consistently predicted worse prostate cancer outcomes.
• ▪The Decipher test analyzes cellular genetics from an existing tissue biopsy to measure tumor aggressiveness and evaluate spreading risk on a numerical scale.

Abiraterone treatment for prostate cancer

• ▪A study led by University College London showed that combining standard treatment with the hormone therapy abiraterone halved mortality risks and slowed disease progression in high-risk prostate cancer cases.
• ▪In January 2026, NHS England expanded eligibility for abiraterone to include men whose high-risk prostate cancer had not yet spread to other areas.