OMass Therapeutics closed an oversubscribed $310 million Series C to advance its endocrinology and immunology programs. The company said the bulk of proceeds will support OMS1620 through Phase II development for congenital adrenal hyperplasia (CAH) and ACTH-dependent Cushing’s syndrome, with an emphasis on extending receptor residency time. The financing also funds early clinical work on a second candidate, SLC15A4, positioned for lupus and other interferon-linked conditions. New investors include Bain Capital Life Sciences, Forbion, and Novo Holdings, alongside participation from existing backers such as Syncona and Sanofi Ventures. OMass’ CEO Ros Deegan said the raise was timed to strengthen the balance sheet and generate “meaningful data” across both programs.