Dive Brief:

• Biotechnology startup Clasp Therapeutics launched on Wednesday with $150 million in financing to develop a group of dual-pronged cancer immunotherapies for tough-to-treat tumors. 
• The Series A raise led by Catalio Capital Management, Third Rock Ventures and Novo Holdings will support a portfolio of so-called T cell engagers, a popular type of medicine that draws immune cells to tumors. Clasp expects to generate human data from its first drug prospects before raising more funding, according to CEO Robert Ross. 
• Clasp hasn’t disclosed which cancers it’s focusing on first. But the company claims its drugs have the potential to target tumors more precisely than similar, existing methods.  

Dive Insight:

Clasp is working in a fast-moving area of cancer research. It’s focused on “bispecific” T-cell engagers, which grab targets on tumors and immune cells to trigger a potent attack on cancer.

These medicines are seen, in some cases, as more convenient, “off-the-shelf” alternatives to personalized cellular medicines. In recent years, they’ve come of age, with multiple drugs winning approvals in blood cancers like lymphoma and multiple myeloma. 

But bispecific drugs are flawed, too. The targets they seek out can also be found on healthy cells, leading to side effects that can force drugmakers to test lower doses or make treatment unworkable. 

Those limitations have left room for startups like Clasp, which claims it’s found a better way to target tumors while sparing healthy tissue.

Clasp matches its drug prospects to patients who have a specific type of immune system signature as well as tumor mutations known to drive cancer. The drugs it designs then bind to mutated protein fragments found only on the surface of their tumor cells. 

According to Ross, this strategy should give Clasp the ability to have a “much bigger therapeutic window” and crank up the doses of its drugs higher. 

“I think we can provide a high level of efficacy, but avoid a lot of the safety complications,” he said. There’s also the potential “to help a broad range of patients with a broad range of tumor types.”

Clasp’s approach is based on the work of two pioneering cancer researchers, Bert Vogelstein and Drew Pardoll of Johns Hopkins University. The company was formed in 2020 and has since garnered the support of a wide range of investors. It now employs more than 15 people at facilities in Cambridge, Massachusetts and Rockville, Maryland. Ross, a former executive at Surface Oncology and Bluebird bio, came aboard in November.

Clasp’s work remains early, though. Ross wouldn’t reveal when human tests should begin or any of the tumors the company is targeting. But he said the funding is large enough that Clasp won’t have to worry about rushing to the public markets “as quickly as possible,” and can instead work on pushing its programs forward.

“Here, we have the opportunity to really generate value in collecting data — clinical data — before that happens,” he said.