Merck concludes acquisition of Harpoon Therapeutics

“We continue to augment and diversify our oncology pipeline with innovative approaches to help people with cancer worldwide,” said Dr. Dean Y. Li, president, Merck Research Laboratories. “We are pleased to welcome our Harpoon colleagues to Merck and look forward to working together to advance a novel portfolio of T-cell engagers, including MK-6070.”

Harpoon’s lead candidate, MK-6070 (formerly known as HPN328), is a T-cell engager targeting delta-like ligand 3 (DLL3), an inhibitory canonical Notch ligand that is expressed at high levels in small cell lung cancer (SCLC) and neuroendocrine tumors. The safety, tolerability and pharmacokinetics of MK-6070 is currently being evaluated as monotherapy in a Phase 1/2 clinical trial (NCT04471727) in certain patients with advanced cancers associated with expression of DLL3. The study is also evaluating MK-6070 in combination with atezolizumab in certain patients with SCLC.

In March 2022, the U.S. Food and Drug Administration (FDA) granted Orphan Drug Designation to MK-6070 for the treatment of SCLC.

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Additional pipeline candidates include HPN217, a T-cell engager targeting B-cell maturation antigen (BCMA), currently in Phase 1 clinical development for the treatment of patients with relapsed/refractory multiple myeloma, and several preclinical stage candidates, including HPN601, a conditionally activated targeting epithelial cell adhesion molecule (EpCAM) for the treatment of certain patients with EpCAM expressing tumors.

Under the terms of the merger agreement, Merck, through a subsidiary, has acquired all outstanding shares of Harpoon. As previously disclosed, this transaction is being accounted for as an asset acquisition. Merck is recording a non-tax deductible charge to R&D expense of approximately $650 million. The impact of the transaction on expected full-year non-GAAP EPS is approximately $0.26 per share, which was included in Merck’s full-year 2024 financial outlook issued on February 1, 2024.

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Medical Dialogues team had earlier reported that the U.S. Food and Drug Administration (FDA) had accepted for priority review a new supplemental Biologics License Application (sBLA) of Merck seeking approval for KEYTRUDA, Merck’s anti-PD-1 therapy, in combination with standard of care chemotherapy (carboplatin and paclitaxel), followed by KEYTRUDA as a single agent for the treatment of patients with primary advanced or recurrent endometrial carcinoma. 

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