Merck, Johnson & Johnson Announce Acquisitions to Bolster Respective Oncology Pipelines

Merck has acquired Harpoon Therapeutics with its clinical stage T-cell engager, whereas Johnson & Johnson acquired Ambrx Biopharma with its expertise in next generation antibody drug conjugates and targeted oncologic therapies.

Both Merck and Johnson & Johnson have announced separate acquisitions of biopharmaceutical companies in moves that strengthen their respective oncology pipelines. Merck has acquired Harpoon Therapeutics, Inc. for $23 per share for an approximate total equity value of $680 million, while Johnson & Johnson announced it has acquired Ambrx Biopharma, Inc., in an all-cash merger transaction for a total equity value of approximately $2 billion.1,2

In its acquisition of Harpoon, Merck has gained its lead candidate, HPN328, a T-cell engager that targets the delta-like ligand 3 (DLL3), which is expressed at high levels in patients with small cell lung cancer (SCLC) and neuroendocrine tumors. The novel therapy is being analyzed for safety, tolerability, and monotherapy pharmacokinetics in a Phase I/II clinical trial (NCT04471727) among patients with advanced cancers associated with expression of DLL3. HPN328 is also being evaluated in combination with atezolizumab in patients with SCLC.1

Merck also gains a portfolio of novel T-cell engagers using Harpoon’s proprietary Tri-specific T cell Activating Construct (TriTAC) platform. The engineered protein technology directs a patient’s own immune cells to eliminate tumor cells, whereas the ProTriTAC platform works with the TriTAC platform to develop a therapeutic T-cell engager that is inactive until it reaches the tumor.

“At Merck, we continue to enhance our oncology pipeline through strategic acquisitions that complement our current portfolio and advance breakthrough science to help address the needs of people with cancer worldwide,” Dean Y. Li, MD, PhD, president, Merck Research Laboratories, said in a press release.1 “This agreement reflects the creativity and commitment of scientists and clinical development teams at Harpoon. We look forward to further evaluating HPN328 in innovative combinations with other pipeline candidates.”

Other pipeline candidates acquired by Merck in the deal include the Phase I HPN217, which targets the B-cell maturation antigen and is currently in development for relapsed/refractory multiple myeloma, as well as several other preclinical stage novel therapies.

“At Harpoon, we have always been committed to advancing our cancer immunotherapy candidates to improve the lives of patients. With Merck’s recognized leadership in oncology clinical development and global commercial footprint, our lead candidate, HPN328, is well positioned moving forward,” Julie Eastland, president and chief executive officer, Harpoon Therapeutics, said in a press release.1 “The talented, passionate and dedicated Harpoon team has made great progress over the past eight years in leveraging our research platform to develop an innovative suite of candidates, and we are pleased that Merck has recognized the significant potential of our pipeline. I want to personally thank all of our key stakeholders, including our entire team at Harpoon, trial participants, physicians and our shareholders, who have supported us.”

With its acquisition, Johnson & Johnson gains a proprietary synthetic biology technology platform to develop next-generation antibody drug conjugates (ADCs).2 Among the pipeline candidates are ADC ARX517, which targets PSMA for metastatic castration-resistant prostate cancer; ARX788, an ADC that targets HER2 for metastatic HER2-positive breast cancer; and ARX305, an ADC that targets CD-70 for renal cell carcinoma.2

“Ambrx’s ADC technology offers unique advantages in the conjugation of stable antibodies and cytotoxic linker payloads, which results in engineered ADCs that effectively kill cancer cells and limit toxicities,” said Yusri Elsayed, MD, MHSc, PhD, global therapeutic area head, Oncology, Johnson & Johnson Innovative Medicine, in a press release.2 “The results seen to date with ARX517 in mCRPC are promising and represent a potential first- and best-in-class targeted therapy for the treatment of this aggressive disease. In addition, Ambrx’s pipeline and ADC platform present exciting future opportunities to deliver enhanced, precision biologics as we look to transform the treatment of cancer and improve patients’ lives.”


1. Merck to Acquire Harpoon Therapeutics, Further Diversifying Oncology Pipeline. Merck. News release. January 8, 2024.

2. Johnson & Johnson to Acquire Ambrx, Advancing Next Generation Antibody Drug Conjugates to Transform the Treatment of Cancer. Johnson & Johnson. News release. January 8, 2024.

Leave a Reply

Your email address will not be published. Required fields are marked *