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Palleon Lands $48M to Develop New Type of Checkpoint Cancer Drug

Xconomy Boston — 

[Corrected 10/4/17, 9:11 a.m. See below.] A Waltham, MA biotech aiming to activate more parts of the immune system in the fight against tumors announced a $47.6 million Series A round of funding from a syndicate of corporate investors.

Palleon Pharmaceuticals is developing three antibodies that aim to reactivate immune system activity after having been tricked into passivity by glycans, sugar molecules present on tumor cells. If it sounds similar to other cancer research, it is. Dozens of companies have been pursuing treatments that try to get the immune system’s T cells to once again attack tumors, after proteins on the tumors trick checkpoints on the T cells into believing the tumor is not dangerous. [Corrected amount of Series A funding in first paragraph and headline.]

Palleon is taking that concept and applying it to the sugary glycans that sit on the surface of the tumors, which the company says suppress T cells and other parts of the body’s immune system—dendritic cells, macrophages, and NK cells—into inactivity, says CEO Jim Broderick. Palleon targets those parts of the immune system that are meant to sense the tumors, but are instead being suppressed by the glycans—an approach that Broderick says was demonstrated scientific founder Carolyn Bertozzi, a professor of chemistry at Stanford and researcher at the Howard Hughes Medical Institute.

“An immune response to tumors requires a coordination of multiple different cell types and there’s multiple mechanisms that are stopping these immune cell types,” Broderick says. “What you want to do is make it so the tumor can use this checkpoint access to evade immunosuppressant activity.”

Another scientific co-founder, Paul Crocker, discovered the family of receptors that the company is targeting. Crocker is a professor of glycoimmunology and the head of the cell signaling and immunology division at the University of Dundee, Scotland.

Palleon calls its treatments glycoimmune checkpoint inhibitors, riffing off of well-known checkpoint inhibitor treatments such as Merck’s (NYSE: MRK) pembrolizumab (Keytruda) and Bristol-Myers Squibb’s (NYSE: BMY) nivolumab (Opdivo). Checkpoint inhibitors disrupt “checkpoint” proteins that tumors use to hide from the immune system, but have only been successful in a minority of patients. Since those drugs came to market, researchers have rushed to develop new versions or make cocktails out of existing ones, which has raised safety concerns among some experts, as Xconomy reported in May.

Other companies are also trying to target tumors by sending antigens after glycans, such as Newton, MA-based Siamab Therapeutics, which has a preclinical treatment for solid tumors. Broderick says glycans have been associated with tumors for more than 50 years, so it’s not a surprise that others are somehow pursuing glycan strategies.

What he contends will set Palleon apart is its targeting of immune cell receptors, not the glycans themselves, which can vary widely. The receptors, however, will cause responses in a wide variety of glycans, he says.

“An excellent team is exploring an attractive area of glycoimmunology to find novel cancer therapeutics,” Peter Seeberger, a professor at the Free University of Berlin and the Max-Planck Institute for Colloids and Surfaces in Potsdam, Germany, wrote in an e-mail when asked to comment on the company.

Palleon’s work is quite young, with all of its candidates in the preclinical stage. Broderick isn’t revealing a timeline on the development or detailing which cancers the drugs will first target.

“This is a mechanism that can be exploited across cancer,” he says. “It’s seen in the whole spectrum of tumors.”

The company also has technology that will allow it to discover which patients have the correct glycans for which treatment, diagnostic work that Broderick says the company may outsource. That will help the company recruit patients when it enters clinical trials, he says.

Investors in the $46.7 million Series A round include the venture capital arms of multiple large pharmaceutical companies, including SR One (GlaxoSmithKline), Pfizer Ventures, Vertex Ventures HC, Takeda Ventures, and AbbVie Ventures. Vertex Ventures HC actually isn’t associated with Vertex Pharmaceuticals, but instead is a part of Temasek Holdings, a sovereign wealth fund for the Singapore government, Broderick says.