Sidewinder Therapeutics secured $137 million in an oversubscribed Series B round to advance bispecific antibody-drug conjugates toward clinical testing. Backed by OrbiMed and multiple investors, the San Diego biotech plans to push a lead program into the clinic in 2027. The company’s approach targets receptor co-complexes expressed on solid tumors to improve selectivity and reduce toxicity, and it previously announced an ADC technology deal with Lonza’s Synaffix BV. The financing underscores sustained investor appetite for next-generation ADC platform differentiation, particularly with bispecific formats and dual-targeting design constraints aimed at broad solid-tumor applicability.