Sidewinder Therapeutics, a San Diego startup focused on next-generation antibody-drug conjugates, raised an oversubscribed $137 million Series B led by OrbiMed and backed by other major investors. The company says it plans to advance a lead bispecific ADC program into the clinic in 2027. Sidewinder was founded in 2023 and has previously announced an ADC technology deal with Lonza’s Synaffix BV. The approach targets receptor co-complexes on solid tumors, with stated oncology focus including colorectal cancer and squamous cell carcinomas of the lung and head and neck. The funding underscores continued investor appetite for ADC innovations designed to improve efficacy and reduce toxicities compared with conventional single-target formats.