Biotechs Sesen and Carisma blend together in bid to transform cancer treatment

Sesen Bio and privately held Carisma Therapeutics are merging, with plans to combine into a “well-funded” biotech that will operate under Carisma’s name and work to advance its engineered macrophages for cancer treatment.    

The merger is set to close in the next three or four months, at which time the biotech will trade on the Nasdaq under the ticker “CARM,” according to a Sept. 21 release.

In a financing round concurrent with the merger proposal, Philadelphia-based Carisma has secured $30 million from several investors, including Big Pharmas AbbVie and Merck & Co. The financing is expected to close alongside the merger.

With the cash expected from both companies and the new $30 million, the combined biotech will have about $180 million in cash, equivalents and marketable securities—money that is expected to fund the company through 2024.

Sesen, which is focused on targeted fusion protein therapeutics to treat cancer, recently hit the brakes on its phase 3 bladder cancer program after talks with the FDA. The Cambridge, Massachusetts-based biotech paused U.S. clinical development of its most advanced product, Vicineum, to preserve cash.

“This transaction represents the result of a thoughtful and careful review of strategic alternatives over the past four months, during which Carisma’s clinical programs, management team and corporate strategy stood out amongst the 42 bids reviewed,” said Thomas Cannell, Sesen’s president and CEO.    

The combined company will work to advance Carisma’s cell therapy platform designed to use engineered macrophages and monocytes to treat cancer. The company’s chimeric antigen receptor macrophage (CAR-M) platform can be used to fine-tune specific immune cell targets, opening the door for potential therapeutic applications beyond oncology.

Carisma’s lead candidate is a CAR-M cell therapy, dubbed CT-0508, which is currently being assessed in a phase 1 clinical trial among patients with advanced HER2+ solid tumors. Carisma is also working to expand its oncology pipeline both independently and via a recent partnership with Moderna, in which the biotech received $45 million cash for the discovery, development and commercialization of in vivo CAR-M therapies.

The Sesen merger will give Carisma financial strength to continue to develop CT-0508 and foster additional strong strategic partnerships, said Steven Kelly, Carisma’s president and CEO. Kelly will lead the combined company once the merger closes.