What changed, and when

Johnson & Johnson acquires Halda Therapeutics on 29 Dec 2025 for $3.05 billion and will account for the deal as a business combination, with an estimated $0.20 total dilution to adjusted EPS split between 2025 and 2026. (J&J press release, Business Wire) Independent reports confirm closing and consideration magnitude. (Reuters preview, Nov 17, 2025, Financial Times preview)

60-second thesis frame

Signal quality is solid for a private, clinical-stage buy: Halda’s RIPTAC modality is a small-molecule induced-proximity approach designed to kill only tumor cells co-expressing a tumor biomarker and an essential survival protein, aiming to overcome resistance that limits today’s precision drugs. (Cell Chem Bio 2024 methods paper) Lead asset HLD-0915 is oral and already in a multi-center Phase 1/2 for mCRPC, with a registered Phase 2 expansion design at NCT06800313. (ClinicalTrials.gov) The strategic fit is clear versus J&J’s prostate franchise and next to approved competitors such as Pluvicto radioligand therapy, which expanded its label in Mar 2025. (FDA Pluvicto label update) Near-term value hinges on reproducible anti-tumor activity, tolerability that supports chronic oral use, and demonstrating differentiation from AR-pathway drugs and PSMA-targeted radioligands. Closing terms and EPS impact now confirmed by the issuer. (J&J press release)

The seven diligence questions

Clinical

• What degree of PSA declines, RECIST responses and durability did HLD-0915 show in Phase 1, and how were prior therapies balanced in responders versus non-responders, per site updates or conference posters? (Halda news summary, Oct 24, 2025)
• Does the RIPTAC “hold-and-kill” mechanism translate into a predictable therapeutic window in humans, and are on-target AEs manageable at doses planned for Phase 2? (Cell Chem Bio 2024, ClinicalTrials.gov NCT06800313)

Payer or Access

• If approved, how will US payers position an oral, targeted therapy for post-ARPI mCRPC relative to Pluvicto’s expanded, pre-taxane use, and what step edits could emerge? (FDA Pluvicto expansion, Mar 28, 2025)
• Will coding and distribution align to retail or specialty pharmacy under Part D, and how would that compare with radiopharmaceutical buy-and-bill dynamics that currently favor center-based care? (Context from FDA labels for analogues, Xtandi label, Pluvicto label)

Ops or Adoption

• Can J&J scale companion-like biomarker testing workflows needed to identify the tumor-protein target for RIPTACs, with turnarounds suitable for community urology and oncology? (Modality background, Cell Chem Bio 2024)

Competitive

• Where does an oral RIPTAC sit versus AR-pathway inhibitors and PSMA-targeted agents in future NCCN-like sequences, given earlier use of agents such as enzalutamide and the broadened Pluvicto label? (Xtandi label, FDA Pluvicto expansion)

Team or Cap table

• How are key Halda scientists and program leaders retained post-close, and are milestone or earn-out constructs tied to clinical inflections? (J&J press release)

Red flags

• Platform novelty risk, first-in-class induced-proximity cytotoxicity in solid tumors may face unforeseen human toxicities or heterogeneous biomarker expression that blunts benefit. (Mechanism overview, Cell Chem Bio 2024)
• Competitive pressure from PSMA-targeted radioligands moving earlier in disease, potentially shrinking second-line mCRPC share where new orals often start. (FDA Pluvicto expansion, WSJ on Pluvicto Phase 3 signal)
• Earnings drag is modest but real, and press reports previously cited different EPS impacts, so investors should anchor on the issuer’s closing update that pegs about $0.20 total, split across 2025–2026. (J&J press release, Reuters preview with prior estimate)

Next catalyst

First detailed 2026 clinical update for HLD-0915 is plausible at ASCO GU 2026 if submitted, Feb 26–28, 2026, Moscone West, San Francisco. (ASCO GU 2026 program page, ASCO GU dates). Backup venue if timelines slip: mid-year oncology meetings. (Calendar context, Hematology/Oncology meeting calendar)

FAQ

• What exactly changed by J&J’s completion of the Halda Therapeutics acquisition on 29 Dec 2025, and why does it matter for prostate cancer?
  The deal closed, bringing Halda’s RIPTAC platform and lead oral candidate HLD-0915 for mCRPC into J&J, which aims to expand in precision oncology. (J&J press release, Business Wire)
• What is the regulatory path after the Halda acquisition by J&J and what are the next formal steps in the US, UK, and EU?
  HLD-0915 remains investigational in a Phase 1/2 trial registered at NCT06800313, so next steps are dose-expansion data and potential end-of-Phase-2 interactions before pivotal design. No marketing applications are filed. (ClinicalTrials.gov)
• Which endpoints in the HLD-0915 program drove the early signal referenced in the announcement, and how meaningful was the effect size?
  Company communications highlighted PSA reductions and RECIST responses with a favorable tolerability profile in heavily pretreated mCRPC from first-in-human experience, though full datasets are not yet peer-reviewed. (Halda news, Oct 24, 2025)
• What safety issues matter post-completion of the Halda acquisition and do they change real-world use if approved?
  As a first-in-class induced-proximity cytotoxic, on-target effects in normal tissues are the key watch-out, and chronic oral dosing must avoid cumulative toxicity. Label analogues for current standards of care show different risk profiles, which will shape sequencing. (Xtandi label, Pluvicto label)
• How will major US payers treat access after a future approval of HLD-0915, including prior auth or step edits, and are codes available?
  If approved as an oral targeted agent, HLD-0915 would likely adjudicate under Part D with specialty-pharmacy distribution and prior authorization anchored to biomarker status and prior ARPI exposure, while Pluvicto remains a procedure-based Part B therapy with site and imaging logistics. (FDA Pluvicto expansion, context from labels Xtandi)

Publisher / Disclosure

Publisher: LucidQuest Ventures Ltd. Produced: 30 Dec 2025, 13:00 London. Purpose: general and impersonal information. Not investment research or advice, no offer or solicitation, no suitability assessment. UK: directed at investment professionals under Article 19(5) and certain high-net-worth entities under Article 49(2)(a)–(d) of the Financial Promotion Order 2005. Others should not act on this. Sources and accuracy: public sources believed reliable, provided “as is,” may change without notice. No duty to update. Past performance is not reliable. Forward-looking statements carry risks. Methodology: questions-first framework using public sources. No conflicts. Authors do not hold positions unless stated. © 2025 LucidQuest Ventures Ltd.

Entities / Keywords

Johnson & Johnson; JNJ; Halda Therapeutics; RIPTAC; Regulated Induced Proximity Targeting Chimeras; HLD-0915; metastatic castration-resistant prostate cancer; mCRPC; NCT06800313; induced proximity; small-molecule proximity; oral oncology; prostate-specific membrane antigen; PSMA; Pluvicto; lutetium Lu 177 vipivotide tetraxetan; enzalutamide; Xtandi; abiraterone; Zytiga; FDA; EMA; ASCO GU 2026; ClinicalTrials.gov; Cell Chemical Biology; induced-proximity cytotoxicity; biomarker-defined therapy; payer access; Part D; specialty pharmacy; EPS dilution; $3.05 billion acquisition; business combination; Yale spinout.