With this acquisition, MSD bolsters its oncology pipeline as Harpoon has two immunotherapies in early-stage development – one for a type of lung cancer and the other for multiple myeloma.

Harpoon has developed a portfolio of novel T-cell engagers and its lead candidate, HPN328, is currently being evaluated in a Phase 1/2 clinical trial as monotherapy in patients with advanced small cell lung cancer (SCLC) and neuroendocrine tumors. The study is also evaluating HPN328 in combination with atezolizumab in patients with small cell lung cancer (SCLC).

Additional pipeline candidates include HPN217, currently in Phase 1 clinical development for the treatment of patients with relapsed/refractory multiple myeloma, and several preclinical stage candidates, including HPN601, for the treatment of patients with epithelial cell adhesion molecule (EpCAM) expressing tumors.

“With Merck’s recognized leadership in oncology clinical development and global commercial footprint, our lead candidate, HPN328, is well positioned moving forward,” said Julie Eastland, president and CEO of Harpoon Therapeutics. “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.”

Closing of the acquisition, which has been unanimously approved by Harpoon’s board of directors, is expected in the first half of 2024.