# Clasp Therapeutics

Source: https://onco.cc/companies/clasp-therapeutics/  
OnCo record `clasp-therapeutics` (Company). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Clasp Therapeutics makes off-the-shelf T cell engagers that recognise fragments of mutated cancer proteins, such as mutant p53 and KRAS, shown on the surface of tumour cells. Its first medicine, for cancers with a specific p53 mutation, has been in a phase 1 trial since 2025.

## Summary

Clasp Therapeutics, co-founded by Bert Vogelstein and Drew Pardoll of Johns Hopkins University, launched on 20 March 2024 with a USD 150 million Series A led by Catalio Capital Management, Third Rock Ventures and Novo Holdings. Its pHLAre molecules are bispecific T cell engagers that bind a mutant peptide presented by a particular HLA type on cancer cells and recruit T cells to kill them, reaching driver mutations inside the cell that conventional antibodies cannot. The lead CLSP-1025 targets the p53 R175H mutant peptide on HLA-A*02:01 and dosed its first patient in the phase 1 GUARDIAN-101 trial (NCT06778863) in April 2025, with data presented at ESMO 2025. CLSP-5282, a T cell engager against the KRAS G12V peptide on HLA-A*03:01, was unveiled at AACR 2026. The company is based in Cambridge, Massachusetts, with a site in Rockville, Maryland.

## Fields

- Kind: Company
- Last checked: 2026-10-29
- HQ: Cambridge, MA
- Type: biotech
- Website: https://www.clasptx.com/

## Notes

- Founding year not stated; the company launched publicly on 20 March 2024. Only patients whose tumours carry the exact mutation and HLA type can be eligible for each molecule.

## Sources

- Official website: https://www.clasptx.com/
- Launch and USD 150 million Series A, March 2024: https://www.clasptx.com/press-release-publications/clasp-therapeutics-launches-with-150-million-to-pioneer-precision-immuno-oncology-using-next-generation-t-cell-engagers-with-unparalleled-specificity
- GUARDIAN-101 data at ESMO 2025: https://www.clasptx.com/press-release-publications/esmo2025
- CLSP-5282 at AACR 2026: https://www.clasptx.com/press-release-publications/clasp-therapeutics-unveils-first-in-class-kras-t-cell-engager-clsp-5282-at-aacr-2026

## Connected records

- fronts: [Immunotherapy](https://onco.cc/fronts/immunotherapy/)
- technologies: [Bispecific antibodies](https://onco.cc/technologies/bispecific-antibody/), [T-cell engagers (bispecific)](https://onco.cc/technologies/t-cell-engager/)
- targets: [CD3](https://onco.cc/targets/cd3/), [KRAS](https://onco.cc/targets/kras/), [TP53](https://onco.cc/targets/tp53/)
- trials: [CLSP-1025 in p53 R175H solid tumors](https://onco.cc/trials/nct06778863/)
- companies: [ACS BrightEdge (American Cancer Society)](https://onco.cc/companies/acs-brightedge/), [Alexandria Venture Investments](https://onco.cc/companies/alexandria-venture-investments/), [Novo Holdings](https://onco.cc/companies/novo-holdings/), [Third Rock Ventures](https://onco.cc/companies/third-rock-ventures/)

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