Merck, known as MSD outside of the United States and Canada, announced the completion of the acquisition of Harpoon Therapeutics. Harpoon is now a wholly-owned subsidiary of Merck, and Harpoon’s common stock will no longer be publicly traded or listed on the Nasdaq Stock Market.

“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.

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.