# Sidewinder Therapeutics

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

## TL;DR

Sidewinder Therapeutics designs antibody-drug conjugates that bind two proteins found together on some solid tumours, so the cell-killing drug is taken up mainly by cancer cells. It is aiming at squamous lung, head and neck and bowel cancers, with its first human trial expected in 2027.

## Summary

Sidewinder Therapeutics, founded in San Diego in 2023 with OrbiMed as sole Series A investor, develops bispecific antibody-drug conjugates directed at receptor co-complexes that are highly expressed on certain solid tumours, pairing a target that drives the cancer with one that carries the conjugate into the cell. Programmes are aimed at squamous cell carcinomas of the lung and of the head and neck and at gastrointestinal cancers including colorectal cancer; targets are undisclosed. In January 2026 it took a multi-target licence to Lonza's Synaffix conjugation technology, and on 8 April 2026 it announced an oversubscribed USD 137 million Series B co-led by Frazier Life Sciences and Novartis Venture Fund, bringing total funding to USD 162 million. The company expects its lead programme to enter clinical development in 2027.

## Fields

- Kind: Company
- Last checked: 2026-10-29
- HQ: San Diego, CA
- Type: biotech
- Website: https://sidewinderbio.com/

## Notes

- The Series A amount and date are not given in the company's release; only OrbiMed's role as sole Series A investor is stated. Sidewinder emerged publicly with the April 2026 Series B. Lead targets are confidential.

## Sources

- Official website: https://sidewinderbio.com/
- USD 137 million Series B, April 2026: https://sidewinderbio.com/news/sidewinder-therapeutics-announces-137-million-series-b-financing-to-advance-precision-bispecific-adcs-into-clinical-development-for-cancer/
- Synaffix licence, January 2026: https://sidewinderbio.com/news/lonzas-synaffix-and-sidewinder-therapeutics-announce-multi-target-license-agreement-to-advance-development-of-next-generation-bispecific-adcs/

## Connected records

- cancers: [Colorectal cancer](https://onco.cc/cancers/colorectal/), [Head and neck squamous cell carcinoma](https://onco.cc/cancers/head-and-neck/), [Non-small-cell lung cancer](https://onco.cc/cancers/nsclc/)
- fronts: [Antibody-Drug Conjugates](https://onco.cc/fronts/adcs/)
- technologies: [Antibody-drug conjugate (ADC)](https://onco.cc/technologies/adc/), [Bispecific ADC](https://onco.cc/technologies/bispecific-adc/)
- companies: [Alexandria Venture Investments](https://onco.cc/companies/alexandria-venture-investments/), [DCVC](https://onco.cc/companies/dcvc/), [Frazier Life Sciences](https://onco.cc/companies/frazier-life-sciences/), [Longwood Fund](https://onco.cc/companies/longwood-fund/), [Novartis Venture Fund](https://onco.cc/companies/novartis-venture-fund/), [OrbiMed](https://onco.cc/companies/orbimed/), [Samsara BioCapital](https://onco.cc/companies/samsara-biocapital/)

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