JNJ-6143 / J&J - LARVOL DELTA

Preliminary safety, pharmacokinetics, and antitumor activity of HLD-0915, a first-in-class oral RIPTAC™ binding androgen receptor (AR) and bromodomain 4 (BRD4), in patients with metastatic castrate resistant prostate cancer (mCRPC) (AACR-NCI-EORTC 2025) - P1/2 | "Dose expansion of HLD-0915 is ongoing. The encouraging safety and anti-tumor activity is proof of concept for RIPTACs in other tumor types."

Clinical • Late-breaking abstract • Metastases • PK/PD data • Castration-Resistant Prostate Cancer • Genito-urinary Cancer • Oncology • Prostate Cancer • Solid Tumor • AR • BRD4

A Study of JNJ-101556143 in Participants With Metastatic Prostate Cancer (clinicaltrials.gov) - P2 | N=100 | Not yet recruiting | Sponsor: Janssen Research & Development, LLC

New P2 trial • Genito-urinary Cancer • Oncology • Prostate Adenocarcinoma • Prostate Cancer • Solid Tumor

Safety and efficacy of JNJ-6143, a first-in-class oral AR-targeted regulated induced proximity targeting chimera at the optimal dose for further development in patients with mCRPC/mAPMR, including high-risk molecular features (ESMO 2026) - No abstract available

Clinical • Castration-Resistant Prostate Cancer • Oncology • Prostate Cancer

HLD-0915: could it be the breakthrough drug we need for metastatic prostate cancer? (PubMed, Expert Opin Investig Drugs) - No abstract available

Journal • Genito-urinary Cancer • Oncology • Prostate Cancer • Solid Tumor

HLD-0915-ONC-101: Study of HLD-0915 (JNJ-101556143) in Patients With Metastatic Prostate Cancer (clinicaltrials.gov) - P1/2 | N=190 | Recruiting | Sponsor: Janssen Research & Development, LLC | Trial completion date: Apr 2030 ➔ Jul 2028 | Trial primary completion date: Apr 2028 ➔ Jul 2028

Trial completion date • Trial primary completion date • Castration-Resistant Prostate Cancer • Genito-urinary Cancer • Oncology • Prostate Adenocarcinoma • Prostate Cancer • Solid Tumor

A Study of JNJ-87189401 Combined With JNJ-78278343 for Advanced Prostate Cancer (clinicaltrials.gov) - P1 | N=355 | Recruiting | Sponsor: Janssen Research & Development, LLC | N=250 ➔ 355

Enrollment change • Castration-Resistant Prostate Cancer • Genito-urinary Cancer • Oncology • Prostate Adenocarcinoma • Prostate Cancer • Solid Tumor

HLD-0915-ONC-101: Study of HLD-0915 in Patients With Metastatic Prostate Cancer (clinicaltrials.gov) - P1/2 | N=190 | Recruiting | Sponsor: Halda Therapeutics OpCo, Inc. | N=33 ➔ 190 | Trial completion date: Mar 2027 ➔ Apr 2030 | Trial primary completion date: Mar 2027 ➔ Apr 2028

Enrollment change • Trial completion date • Trial primary completion date • Castration-Resistant Prostate Cancer • Genito-urinary Cancer • Oncology • Prostate Adenocarcinoma • Prostate Cancer • Solid Tumor

Translational Molecular Imaging of Transmembrane AMPAR Regulatory Proteins in the Human Brain (SNMMI 2026) - "We developed 18F-Tarplify as a novel molecular imaging tool for quantitative assessment of TARP γ8 in the living human brain. Robust tracer kinetics and strong concordance among autoradiography, SUV, VT, and BPND data were confirmed in both rodents, NHPs and humans, supporting its utility for therapeutic monitoring and precision imaging of TARP γ8–modulating interventions in patients."

CNS Disorders • Mental Retardation

Development and preclinical evaluation of TARP-γ8 PET tracer [18F]TARP-2306 (SNMMI 2026) - "[18F]TARP-2306 demonstrates high affinity, regional specificity, and reliable in vivo quantification of TARP-γ8. Multimodal correlation, knockout validation, and disease-model sensitivity collectively support its utility for mapping AMPAR auxiliary-subunit biology and investigating TARP-γ8 related neuropathology. The findings highlight the translational potential of [18F] TARP-2306 for further clinical study."

Preclinical • CNS Disorders • Epilepsy • Mental Retardation

Halda Therapeutics announced today that it has entered into a definitive agreement pursuant to which Johnson & Johnson will acquire Halda for $3.05 billion… (GlobeNewswire) - "Halda’s portfolio includes HLD-0915, a first-in-class, oral RIPTAC therapeutic, in development for metastatic castration-resistant prostate cancer (mCRPC)....The transaction is expected to close within the next few months, subject to the satisfaction of customary closing conditions, including expiration of the applicable waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976."

M&A • Castration-Resistant Prostate Cancer

Preliminary safety, pharmacokinetics, and antitumor activity of HLD-0915, a first-in-class oral RIPTAC™ binding androgen receptor (AR) and bromodomain 4 (BRD4), in patients with metastatic castrate resistant prostate cancer (mCRPC) (AACR-NCI-EORTC 2025) - P1/2 | "Dose expansion of HLD-0915 is ongoing. The encouraging safety and anti-tumor activity is proof of concept for RIPTACs in other tumor types."

Clinical • Metastases • PK/PD data • Castration-Resistant Prostate Cancer • Genito-urinary Cancer • Oncology • Prostate Cancer • Solid Tumor • AR • BRD4

Halda Therapeutics Announces First-in-Human Results for HLD-0915, an Oral RIPTAC Therapeutic Demonstrating Encouraging Safety and Anti-Tumor Activity in Metastatic Castration-Resistant Prostate Cancer (mCRPC) (GlobeNewswire) - "At the data cut-off, among all 31 patients who received at least one dose of HLD-0915, 13 (31%) achieved a PSA50 response and 7 (23%) achieved a PSA90 response. The median time to PSA50 across doses was 37 days (between 1-2 cycles). Among the 22 patients who completed at least 2 cycles of therapy, 59% achieved a PSA50 response and 32% achieved a PSA90 response....The Phase 2 expansion is expected to begin in late 2025."

P1 data • Trial status • Castration-Resistant Prostate Cancer

Halda Therapeutics Announces Oral Plenary Presentation on HLD-0915 Clinical Data in Metastatic Castration-Resistant Prostate Cancer (mCRPC) at 2025 AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics on October 24, 2025 (GlobeNewswire) - "...Halda will present clinical and safety data from its first-in-human, multicenter, open label Phase 1/2 study (NCT06800313) to evaluate monotherapy safety, tolerability, and clinical activity of orally administered HLD-0915 AR-BRD4 RIPTAC therapeutic in patients with mCRPC."

P1/2 data • Castration-Resistant Prostate Cancer

Halda Therapeutics Receives FDA Fast Track Designation for HLD-0915 for the Treatment of Metastatic Castration-Resistant Prostate Cancer (The Manila Times) - "Halda is currently enrolling patients in the first-in-human, Phase 1/2 clinical trial (NCT06800313) to evaluate the safety and tolerability of HLD-0915 in the treatment of metastatic castration-resistant prostate cancer (mCRPC)."

Fast track • Castration-Resistant Prostate Cancer

RIPTACs for Precision Cancer Therapy: A Novel Modality with the Inspiration of HLD-0915 as the First Candidate in Clinical Trials. (PubMed, J Med Chem) - No abstract available

Journal • Oncology

An oral prostate cancer RIPTAC therapeutic in phase 1 for metastatic castrate resistant prostate cancer (mCRPC). (ASCO 2025) - P1/2 | "Cohort 1 enrollment begins in January 2025. The Phase 2 portion of the study will confirm the RP2D and clinical activity in up to 3 cohorts which will be decided in the future based on emerging data."

Metastases • P1 data • Castration-Resistant Prostate Cancer • Genito-urinary Cancer • Oncology • Oral Cancer • Prostate Cancer • Solid Tumor

Halda Therapeutics Announces First Patient Dosed in Phase 1/2 Clinical Trial Evaluating HLD-0915 in Metastatic Castration-Resistant Prostate Cancer (Businesswire) - "Halda Therapeutics...announced that the first patient has been dosed in the first-in-human Phase 1/2 clinical trial (NCT06800313) to evaluate the safety and tolerability of HLD-0915 in the treatment of metastatic castration-resistant prostate cancer (mCRPC)....The Phase 1/2 open label, multi-center clinical trial is designed to evaluate the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and anti-tumor activity of orally administered, single-agent HLD-0915 in mCRPC patients....The Phase 1/2 clinical study could enroll up to 80 mCRPC patients."

Trial status • Castration-Resistant Prostate Cancer

A Study of HLD-0915 in Patients with Metastatic Castration Resistant Prostate Cancer (mCRPC) (clinicaltrials.gov) - P1/2 | N=33 | Recruiting | Sponsor: Halda Therapeutics OpCo, Inc. | Not yet recruiting ➔ Recruiting

Enrollment open • Castration-Resistant Prostate Cancer • Genito-urinary Cancer • Oncology • Prostate Adenocarcinoma • Prostate Cancer • Solid Tumor

A Study of HLD-0915 in Patients with Metastatic Castration Resistant Prostate Cancer (mCRPC) (clinicaltrials.gov) - P1/2 | N=33 | Not yet recruiting | Sponsor: Halda Therapeutics OpCo, Inc.

New P1/2 trial • Castration-Resistant Prostate Cancer • Genito-urinary Cancer • Oncology • Prostate Adenocarcinoma • Prostate Cancer • Solid Tumor

Halda Therapeutics Secures $126 Million Financing to Advance RIPTAC Cancer Therapies into the Clinic for Major Solid Tumors (Businesswire) - "Halda Therapeutics...announced that it has raised new financing of $126 million in a Series B extension...Including this financing, Halda has raised $202 million to date from investors. Proceeds from the financing will be used to advance two RIPTAC candidates into clinical trials for patients with prostate cancer and breast cancer, initially in the metastatic setting where drug resistance to standard of care is prevalent. Halda’s lead RIPTAC therapeutic, HLD-0915, is expected to initiate a Phase 1 clinical trial in the first half of 2025 for the treatment of patients with metastatic, castration-resistant prostate cancer (mCRPC). The financing will also support the clinical development of a second RIPTAC therapeutic for metastatic breast cancer."

Financing • New P1 trial • Breast Cancer • Castration-Resistant Prostate Cancer • Genito-urinary Cancer • Metastatic Castration-Resistant Prostate Cancer • Oncology • Prostate Cancer • Solid Tumor

Halda Therapeutics Announces Publication in Cell Chemical Biology Demonstrating Proof-of-Mechanism and Pharmacology of RIPTAC Therapeutics for Precision Treatment of Cancer (Businesswire) - "The publication details several chemical biology approaches using a model with a HaloTag‑FKBP target protein to dissect the mechanism of action and pharmacology of RIPTAC molecules. Key findings from the study include: RIPTAC therapeutics demonstrated selective anti-proliferative activity in cells expressing the target protein; A ternary complex formed by the target protein, the RIPTAC molecule, and a pan-essential protein abrogated the function of the essential protein selectively in target-expressing cells, causing cell death; Several different pan-essential cellular proteins were shown to be amenable for selective cancer cell killing when incorporated into RIPTAC ternary complexes."

Preclinical • Oncology

Prostate cancer RIPTAC™ therapeutics demonstrate activity in preclinical models of Enzalutamide-resistant prostate cancer (AACR 2023) - "RIPTACs were optimized for oral bioavailability, and tumor ternary complex formation in prostate cancer cell line-derived xenograft models. RIPTAC therapeutics display nanomolar in vitro potency in AR:RIPTAC:EP ternary complex formation, which results in abrogation of the EP function and antiproliferative activity in prostate cancer cell lines, but not in AR-knockout control cells. Taken together, our in vitro mechanistic data and in vivo PD/efficacy observations in multiple prostate cancer models support further investigation of prostate cancer RIPTAC therapeutics as a novel heterobifunctional therapeutic modality in mCRPC."

Preclinical • Genito-urinary Cancer • Oncology • Prostate Cancer • Solid Tumor • AR • CASP3 • CASP7

Halda Therapeutics Presents Preclinical Data for RIPTAC Therapeutics Demonstrating Oral Efficacy as a Monotherapy for the Treatment of Prostate Cancer (Businesswire) - "Halda Therapeutics...announced a poster presentation for its lead RIPTAC therapeutic program for prostate cancer at the annual meeting of the American Association for Cancer Research (AACR) being held in Orlando, Florida, from April 14-19, 2023. The preclinical data showed oral efficacy of the RIPTAC therapeutics as a monotherapy and demonstrated anti-tumor activity superior to the standard of care agent in prostate cancer, enzalutamide. Combination therapy with PARP inhibitors is also being explored and RIPTAC therapeutics may have a complementary mechanism."

Preclinical • Genito-urinary Cancer • Oncology • Prostate Cancer • Solid Tumor

Biotech Drug Shown to Kill Prostate Tumor Cells - "'Riptac therapeutics address a shortcoming shared by most current pharmaceutical modalities,' says Crews in a Halda Therapeutics statement, & namely, the reliance on oncogenic driver proteins which can result in drug resistance."

Media quote

An oral androgen receptor RIPTAC for prostate cancer. (ASCO-GU 2023) - " We describe here a novel orally bioavailable heterobifunctional small molecule AR RIPTAC that recruits an essential cellular protein (EP) into a stable ternary complex with AR, thereby inhibiting EP function and leading to cell death selectively in AR-positive cells... In summary, we report preclinical data on orally bioavailable heterobifunctional AR RIPTACs that are active in multiple prostate cancer models. The lead molecules are being evaluated in toxicology studies, with IND filing slated for 2024."

Genito-urinary Cancer • Oncology • Prostate Cancer • Solid Tumor • AR