On April 8, 2026, Sidewinder Therapeutics, a biopharmaceutical company pioneering the development of next-generation bispecific antibody-drug conjugates (ADCs) for the treatment of cancer, 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. Wilson Sonsini Goodrich & Rosati advised Sidewinder Therapeutics on the transaction.

The company expects to advance its lead program into clinical development in 2027.

The Wilson Sonsini team that advised Sidewinder Therapeutics on the transaction was led by Lance Brady and Matthew Bresnahan. The team also included:

Corporate
Alison Sechrest
James Reilly

Intellectual Property
Alicia Umpierre

Technology Transactions
Miranda Biven

National Security
Seth Cowell
Anne Seymour

For more information, please see Sidewinder’s news release. Additional coverage can be found on Fierce Biotech.