Novartis-Backed Sidewinder Therapeutics Raises $137M Series B for Bispecific ADCs Targeting Hard-to-Treat Tumors

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Sidewinder Therapeutics closed a $137 million Series B funding round co-led by Novartis Venture Fund and Frazier Life Sciences, bringing total funding to $162 million since 2023.123

The funds will advance bispecific antibody-drug conjugates (ADCs) that target pairs of receptors on cancer cells for improved specificity and reduced off-target effects in solid tumors like bladder, lung, colorectal, head and neck, and squamous cell carcinomas.123

Lead program SWT012, tested in preclinical bladder cancer models, plans IND submission by end of 2026 for 2027 clinical trials; SWT019 (lung cancer) IND in H1 2027, SWT020 (colorectal) advancing.12

Other investors include OrbiMed (Series A lead), Astellas Venture Management, Samsara BioCapital, Goldman Sachs Alternatives, DCVC Bio, Longwood Fund, and Alexandria Venture Investments.123

Announcement made April 8/9, 2026, amid biotech funding challenges, highlighting investor enthusiasm for next-gen ADCs.12

Sources:

1. https://www.biospace.com/business/novartis-backed-sidewinder-collects-137m-series-b-to-strike-at-difficult-to-treat-tumors

2. https://www.fiercebiotech.com/biotech/orbimeds-sidewinder-slithers-toward-clinic-137m-series-b-antibody-drug-conjugates

3. https://www.biopharmadive.com/news/sidewinder-bispecific-antibody-drug-conjugates-orbimed-financing/816942/