Sidewinder Therapeutics emerged from stealth with an oversubscribed $137 million Series B to advance bispecific antibody-drug conjugate programs toward the clinic. The San Diego company’s plan calls for a 2027 debut of a lead program following preparations powered by the fresh funding. The round is backed by a mix of blue-chip investors and comes alongside earlier technology validation: Sidewinder has referenced its ADC approach aimed at receptor co-complexes on solid tumors. The financing is notable because it targets the next wave of ADC differentiation, including attempts to reduce toxicity while improving efficacy in harder-to-treat indications. With ADC competition intensifying across oncology, Sidewinder’s funding signals continued investor appetite for platform-style approaches that can broaden payload and targeting strategies.