Sidewinder Therapeutics Announces $137 Million Series B Financing to Advance Precision Bispecific ADCs into Clinical Development for Cancer

Financing co-led by Frazier Life Sciences and Novartis Venture Fund with significant participation from OrbiMed, Life Sciences at Goldman Sachs Alternatives, DCVC Bio, Samsara BioCapital, Longwood Fund and Astellas Venture Management

SAN DIEGO--(BUSINESS WIRE)--Sidewinder Therapeutics, a biopharmaceutical company pioneering the development of next-generation bispecific ADCs (antibody-drug conjugates) for the treatment of cancer, today announced the closing of an oversubscribed $137 million Series B financing. The round was co-led by Frazier Life Sciences and Novartis Venture Fund, with participation from the sole Series A investor OrbiMed as well as new investors including Life Sciences at Goldman Sachs Alternatives, DCVC Bio, Samsara BioCapital, Longwood Fund, Astellas Venture Management and Alexandria Venture Investments. Concurrent with the financing, Daniel Estes, Ph.D., from Frazier Life Sciences, Michal Silverberg from Novartis Venture Fund, Josh Richardson, M.D., from Life Sciences at Goldman Sachs Alternatives and John Hamer, Ph.D., from DCVC Bio were named to the Board of Directors.

“We are pleased to receive the support of this exceptional group of investors and their shared enthusiasm in advancing Sidewinder’s mission to develop next-generation bispecific ADCs for difficult to treat cancers,” said Eric Murphy, Ph.D., Co-Founder and CEO of Sidewinder Therapeutics. “The ADC field is at an inflection point driven by technological breakthroughs enabling next-generation bispecific ADCs, and Sidewinder is eager to lead this wave of innovation and advance promising therapies for patients with cancer.”

Sidewinder’s mission focuses on developing bispecific ADCs designed to target receptor co-complexes that are highly expressed on certain solid tumors. The pipeline features bispecific antibodies engineered from internally discovered antibody sequences and finely tuned to target tumor-specific co-complexes consisting of an oncogenic driver receptor and an internalizing receptor. Precise targeting of these co-complexes enhances both tumor cell specificity and internalization, thereby improving the delivery of drugs to cancer cells while avoiding normal cells. Sidewinder’s programs are designed to address oncology indications that have limited treatment options and affect substantial patient populations such as squamous cell carcinomas in lung and head and neck cancers as well as gastrointestinal cancers including colorectal cancer. The company expects to advance its lead program into clinical development in 2027.

“Founded on compelling science and a differentiated approach, Sidewinder’s novel bispecific ADC pipeline has the potential to address key hurdles limiting safety and efficacy for this class of therapeutics,” said Daniel Estes, Ph.D., General Partner at Frazier Life Sciences. "We believe that Sidewinder Therapeutics will significantly advance the ADC space and is well positioned to transform the treatment paradigm for cancer patients.”

About Sidewinder Therapeutics

Sidewinder Therapeutics is developing next-generation bispecific ADCs designed to expand the therapeutic window through enhanced tumor specificity and internalization. The company has partnered with Lonza to apply Synaffix's site-specific linker-payload platform across multiple programs. Founded in 2023 with OrbiMed, Sidewinder is headquartered in San Diego and has raised a total of $162 million from a world-class investor syndicate. For more information, visit www.sidewinderbio.com.