AbbVie doubles down on Harpoon with $50M option on BCMA drug

AbbVie and Harpoon Therapeutics are expanding their relationship, inking a $50 million licensing deal for the latter’s BCMA-targeting multiple myeloma candidate and adding up to six new targets to a discovery deal inked in October 2017. 

Under the deal, Harpoon will develop the treatment, called HPN217, through phase 1/2, after which AbbVie may pull the trigger on its option to license the program. In addition to the $50 million upfront fee, Harpoon will collect another $50 million when it doses the first patient with HPN217 in a clinical trial, the companies said in a statement. All told, Harpoon could net as much as $510 million in total from upfront, option and milestone payments. 

HPN217 is a TriTAC, or a tri-specific T call activating construct, which Harpoon believes can overcome the obstacles that have limited the use of T-cell engagers in solid tumors. These constructs are single polypeptides with three binding sites but are a third the size of monoclonal antibodies. Two of those sites bind to cancer antigens and T cells, while the third binds with albumin, a protein in the bloodstream, to extend the molecule’s half-life.  

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Harpoon has two other TriTAC programs in phase 1—HPN424 targets PSMA in prostate cancer and HPN536 targets mesothelin in ovarian cancer. 

“We believe AbbVie is the ideal partner for Harpoon to support the advancement of our BCMA program given the commercial focus of AbbVie in the treatment of this cancer. In addition, we look forward to expanding our discovery collaboration to include up to six additional molecular targets,” said Harpoon CEO Gerald McMahon, Ph.D., in the statement. 

Under the agreement, struck two years ago, Harpoon is engineering TriTACs against “selected targets,” with AbbVie holding onto the right to pursue the development and commercialization of those drugs. The partners did not disclose financial terms at the time. 

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Now, AbbVie has the rights to develop and market two new TriTAC molecules engineered for two targets and has the option to pick up to four more targets. Harpoon stands to collect up to $310 million for each target that AbbVie chooses to advance. 

The news comes a month after AbbVie exited an $850 million kidney and autoimmune disease deal with Reata, a move that the latter attributed to a waning interest in kidney disease on AbbVie’s part, and an increased focus in oncology.