Silverback Therapeutics Extends Series A to $47.5 Million to Advance Pipeline of First-in-Class Systemically Delivered, Locally Active Therapies SEATTLE, September 19, 2018-- Silverback Therapeutics, Inc., a biotechnology company developing a pipeline of systemically delivered, locally active therapies, has closed an extension of its Series A financing to bring the total raised in the round to $47.5 million. The financing was led by existing investor OrbiMed, with participation from new investors Celgene Corporation and Alexandria Venture Investments.