Clasp emerges with $150m for safer T-cell engagers
Clasp Therapeutics chief executive Rob Ross
Clasp Therapeutics has burst onto the T-cell engager (TCE) scene with $150 million in funding for a platform that aims to improve the safety of the class, which is currently gaining traction in cancer immunotherapy.
The new company, based in Cambridge, Massachusetts and Rockville, Maryland, has been set up to commercialise TCE technology developed by Johns Hopkins University researchers Bert Vogelstein and Drew Pardoll. It is led by Rob Ross, founder and chief executive of Surface Oncology, which was sold to Coherus for $67 million last September.
TCEs are a relatively new form of cancer immunotherapy that enhances the immune response by retargeting and activating T-cells so they recognise a specific target on cancer cells, guiding an attack. However, the early entrants in the category have seen their use limited by tolerability issues.
Clasp’s approach is dedicated to improving the safety of TCEs by targeting a cancer-specific peptide in the context of a patient-specific immune signature, known as a human leukocyte antigen (HLA) complex.
In theory, that should make the TCE more selective for cancer cells, sparing healthy tissues from off-target effects, and also provide a way to identify patient populations with the best chance of responding.
Claps claims that its platform can generate bispecific antibody-like molecules that have greater specificity and, unlike some other TCEs, can target intracellular proteins. It combines drug candidates that offer the specificity of CAR-T therapies, but can be used ‘off-the-shelf’ with repeat dosing and are as easy to make as a regular antibody, according to the company.
The first TCE to reach the market was Amgen’s Blincyto (blinatumomab) for B-cell acute lymphoblastic leukaemia (B-ALL) in 2014, which is effective, but is also associated with significant adverse events, including cytokine release syndrome (CRS) and neurotoxicity.
Other TCEs have reached the market in the last few years, mostly CD20- and BCMA-targeted bispecific antibodies for blood cancers and, while their side effects tend to be less severe and frequent than CAR-Ts, they can still be a problem.
Another possible advantage of Clasp’s platform is that it can exploit targets that are expressed at much lower levels on cancer cells than those used to direct current CAR-T and TCE therapies, and that could make it much more applicable to solid tumours. So far, the only TCE approved for a solid tumour is Immunocore’s Kimmtrak (tebentafusp) for uveal melanoma, although, others are in late-stage development.
The round – which will be used to take Clasp’s first candidates into the clinic – was led by Catalio Capital Management, Third Rock Ventures, and Novo Holdings, with participation from Vivo Capital, Cure Ventures, Blackbird BioVentures, Pictet Alternative Advisors, American Cancer Society’s Bright Edge, and Alexandria Venture Investments.
