New Brunswick, N.J. October 25, 2026 /PR Newswire/ – Johnson & Johnson (NYSE:JNJ) today announced promising Phase 1 results for JNJ-6143 (formerly HLD-0915), an investigational once-daily oral Regulated Induced Proximity Targeting Chimera (RIPTAC) small molecule, in patients with advanced prostate cancer who had received multiple prior treatments. Among patients with measurable disease, 75 percent (12 out of 16) had a confirmed complete or partial response assessed by Response Evaluation Criteria in Solid Tumors (RECIST). At the 50 mg dose, 77 percent of patients achieved a confirmed reduction in prostate-specific antigen (PSA) levels of at least 50 percent, and 48 percent had reductions of at least 90 percent. Most treatment-related adverse events were mild to moderate. Data from this study support the selection of the 50-mg once-daily dose for continued clinical development and were presented in a Proffered Paper session at the European Society for Medical Oncology (ESMO) Congress 2026 (#2216O).1
JNJ-6143 is the first investigational molecule from the Company’s RIPTAC platform to advance into clinical studies. The novel mechanism disrupts cancer cell function and triggers cancer cell death using a targeted dual-protein lock between an essential cell survival protein, BRD4, and androgen receptor (AR), a tumor-selective protein, which is highly expressed in prostate cancer cells.
Significant unmet needs remain in advanced prostate cancer
Despite advances in treatment, including therapies that target the AR pathway, chemotherapy and radioligand therapy targeting prostate-specific membrane antigen (PSMA), many patients with advanced prostate cancer experience disease progression and are left with fewer options.2 Median overall survival is approximately two to three years for patients with metastatic androgen pathway modulation-resistant prostate cancer (mAPMR), also known as metastatic castration-resistant prostate cancer (mCRPC), highlighting the need for new treatment approaches with different mechanisms of action.3,4
Expert and company perspectives on the potential of JNJ-6143
“Patients with advanced prostate cancer often go through several treatments as their disease becomes increasingly difficult to control, signaling a significant need for treatments that work differently,” said Professor Johann de Bono, M.D.,* Head of Division: Cancer Biomarkers, Prostate Cancer Targeted Therapy Group, The Adult Drug Development Unit, ICR Cancer Research Institute, London, UK. “These early results with JNJ-6143 are encouraging because we are seeing meaningful anti-tumor activity in patients who have already received multiple therapies. The findings give us confidence to further evaluate this new approach for those with difficult-to-treat disease.”
“For nearly two decades, we have driven progress in prostate cancer care by repeatedly pursuing new scientific approaches with the potential to change the course of the disease,” said Yusri Elsayed, M.D., M.H.Sc., Ph.D., Global Therapeutic Area Head, Oncology, Johnson & Johnson. “JNJ-6143 builds on that approach, bringing a fundamentally different oral mechanism to our prostate cancer pipeline. These early results provide an encouraging foundation for its continued development and our broader exploration of the RIPTAC platform across multiple cancer types.”
Early evidence of deep responses supports continued development
The ongoing Phase 1 study is evaluating the safety and anti-tumor activity of JNJ-6143 and was designed to identify the optimal dose for further study in patients with advanced prostate cancer whose disease progressed after prior treatment. Patients received a median of four prior therapies, including chemotherapy and PSMA-targeted radioligand therapy.1
Among 38 patients receiving the 50-mg once-daily dose, 77 percent had a confirmed reduction of at least 50 percent in PSA, a protein measured in the blood to help monitor prostate cancer, including 48 percent whose PSA levels fell by at least 90 percent. Reductions in PSA were also observed in patients with high-risk molecular features associated with difficult-to-treat disease. Among patients whose tumors could be measured using imaging, 75 percent had a confirmed complete or partial response.1
At the time of the analysis, 71 percent of patients receiving the 50-mg dose remained on treatment, with a median follow-up of 5.6 months. The most common treatment-related adverse events were elevated cholesterol levels (18 percent), nausea (16 percent), and elevated triglyceride levels (16 percent). Four patients (11 percent) interrupted their dose, one patient (three percent) reduced their dose, and one patient (three percent) discontinued treatment due to adverse events.1
The 50-mg once-daily dose will advance into further clinical development, including the Phase 2 study (NCT07832292) of JNJ-6143 in metastatic prostate cancer.5
About the Phase 1 study
The Phase 1 study (NCT06800313) is a multicenter dose-escalation and dose-expansion study of JNJ-6143 in patients with metastatic androgen pathway modulation-resistant prostate cancer (mAPMR) whose disease progressed after one or more androgen receptor pathway inhibitors. The study is evaluating the safety, pharmacokinetics and anti-tumor activity of JNJ-6143 and is designed to determine the maximum tolerated dose and optimal dose for further development. Patients had received a median of four prior therapies, including chemotherapy and PSMA-targeted radioligand therapy.6
The dose-escalation portion evaluated once-daily doses of JNJ-6143 ranging from 12.5 mg to 150 mg, followed by dose expansion randomizing patients 1:1 to receive 25 mg or 50 mg once daily. The 50-mg once-daily dose was identified as the preliminary optimal dose for further development based on the clinical activity, safety and pharmacokinetic data observed in the study.6
About metastatic androgen pathway modulation-resistant prostate cancer (mAPMR)
Metastatic androgen pathway modulation-resistant prostate cancer (mAPMR), also known as metastatic castration-resistant prostate cancer (mCRPC), is an advanced form of prostate cancer that continues to progress despite treatments that target the androgen receptor pathway.2 As the disease progresses, it can spread to other parts of the body, including the bones and lymph nodes, and patients may receive additional treatments such as chemotherapy and radioligand therapy targeting prostate-specific membrane antigen (PSMA).7
Patients with metastatic prostate cancer that has become resistant to androgen pathway modulation face poor outcomes, with survival varying based on factors including the location and extent of disease, prior treatment history and response to therapy. Median overall survival ranges from approximately 13.5 to 31.6 months depending on the site of metastasis.3,4
About JNJ-6143
JNJ-6143 is an investigational, once-daily molecule that uses the novel RIPTAC platform. Its targeted dual-protein lock brings together BRD4, an essential protein for cell survival, and the tumor-selective protein, androgen receptor (AR), which is highly expressed in prostate cancer cells, and is designed to disrupt cancer cell function and trigger cancer cell death.
JNJ-6143 is being evaluated in Phase 1 (NCT06800313) and Phase 2 (NCT07832292) studies in patients with metastatic prostate cancer. It is the first investigational compound from the RIPTAC platform to advance into clinical studies.
In December 2025, Johnson & Johnson completed its acquisition of Halda Therapeutics, adding JNJ-6143 and the RIPTAC platform to its oncology portfolio.
About the Regulated Induced Proximity Targeting Chimera (RIPTAC) platform
The investigational proprietary RIPTAC platform is being explored for the development of oral targeted therapies across multiple tumor types. RIPTAC molecules use a targeted dual-protein lock between an essential protein for cell survival and a tumor-selective protein, designed to disrupt cancer cell function and trigger cancer cell death. Johnson & Johnson is advancing investigational candidates based on the RIPTAC platform, including JNJ-6143 in advanced prostate cancer.
About Johnson & Johnson
At Johnson & Johnson, we believe health is everything. Our strength in healthcare innovation empowers us to build a world where complex diseases are prevented, treated, and cured, where treatments are smarter and less invasive, and solutions are personal. Through our expertise in Innovative Medicine and MedTech, we are uniquely positioned to innovate across the full spectrum of healthcare solutions today to deliver the breakthroughs of tomorrow and profoundly impact health for humanity. Learn more at https://www.jnj.com/ or at www.innovativemedicine.jnj.com. Follow us at @JNJInnovMed.
Cautions Concerning Forward-Looking Statements
This press release contains “forward-looking statements” as defined in the Private Securities Litigation Reform Act of 1995 regarding product development and the potential benefits and treatment impact of JNJ-6143. The reader is cautioned not to rely on these forward-looking statements. These statements are based on current expectations of future events. If underlying assumptions prove inaccurate or known or unknown risks or uncertainties materialize, actual results could vary materially from the expectations and projections of Johnson & Johnson. Risks and uncertainties include, but are not limited to: challenges and uncertainties inherent in product research and development, including the uncertainty of clinical success and of obtaining regulatory approvals; uncertainty of commercial success; manufacturing difficulties and delays; competition, including technological advances, new products and patents attained by competitors; challenges to patents; product efficacy or safety concerns resulting in product recalls or regulatory action; changes in behavior and spending patterns of purchasers of health care products and services; changes to applicable laws and regulations, including global health care reforms; and trends toward health care cost containment. A further list and descriptions of these risks, uncertainties and other factors can be found in Johnson & Johnson’s most recent Annual Report on Form 10-K, including in the sections captioned “Cautionary Note Regarding Forward-Looking Statements” and “Item 1A. Risk Factors,” and in Johnson & Johnson’s subsequent Quarterly Reports on Form 10-Q and other filings with the Securities and Exchange Commission. Copies of these filings are available online at www.sec.gov, www.jnj.com, www.investor.jnj.com or on request from Johnson & Johnson. Johnson & Johnson does not undertake to update any forward-looking statement as a result of new information or future events or developments.
*Prof. de Bono has provided consulting, advisory and speaking services to Johnson & Johnson. He has not been paid for any media work.
Source: Johnson & Johnson
REFERENCES:
1 Garmezy B, et al. Safety and efficacy of JNJ-6143, a first-in-class oral AR-targeted Regulated Induced Proximity Targeting Chimera molecule in patients with mCRPC/mAPMR, including high-risk molecular features. Presented at: European Society for Medical Oncology (ESMO) 2026 Congress; October 24, 2026; Madrid.
2 Kushwaha PP, Gupta S. New insights for drug resistance in metastatic castration-resistant prostate cancer. Cancer Drug Resist. 2022;5(3):846-849. doi:10.20517/cdr.2022.83
3 Wallace KL, Landsteiner A, Bunner SH, et al. Increasing prevalence of metastatic castration-resistant prostate cancer in a managed care population in the United States. Cancer Causes Control. 2021;32(12):1365-1374. doi:10.1007/s10552-021-01484-4
4 Kawahara T, Saigusa Y, Yoneyama S, et al. Development and validation of a survival nomogram and calculator for male patients with metastatic castration-resistant prostate cancer treated with abiraterone acetate and/or enzalutamide. BMC Cancer. 2023;23:214. doi:10.1186/s12885-023-10700-0
5 ClinicalTrials.gov. A Study of JNJ-101556143 in Participants With Metastatic Prostate Cancer. https://clinicaltrials.gov/study/NCT07832292. Accessed October 2026.
6 ClinicalTrials.gov. Study of HLD-0915 (JNJ-101556143) in Patients With Metastatic Prostate Cancer. https://clinicaltrials.gov/study/NCT06800313. Accessed October 2026.
7 Wallace K, Landsteiner A, Bunner S, et al. Epidemiology and mortality of metastatic castration-resistant prostate cancer (mCRPC) in a managed care population in the United States. J Clin Oncol. 2020;38(15_suppl):e13592. doi:10.1200/JCO.2020.38.15_suppl.e13592
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