Ethyreal Bio has launched with $101 million in financing to advance its lead program, ETHY-001, a monoclonal antibody designed to address the underlying driver of both Graves’ disease (GD) and thyroid eye disease (TED).

ETHY-001 represents a potentially novel approach targeting thyroid stimulating hormone receptor (TSHR) activation, a central pathogenic mechanism shared by both TED and GD. Unlike current therapies that typically address either the ocular manifestations of TED or the thyroid dysfunction associated with GD, ETHY-001 is designed to block autoantibody-mediated activation of TSHR, potentially addressing both conditions through a single mechanism-driven therapy.

According to the company, ETHY-001 is engineered to comprehensively inhibit disease activity while supporting a safety profile suitable for long-term administration. The antibody incorporates half-life extension technology intended to enable infrequent dosing and is formulated for low-volume subcutaneous delivery, with plans to develop an autoinjector.

“GD and TED are prevalent and debilitating conditions with a shared causal driver—pathogenic stimulating autoantibodies to the TSHR,” said Niranjan Kameswaran, PhD, CEO of Ethyreal Bio. “These two conditions frequently co-exist in the same individual, yet current treatments for GD do not treat or prevent TED, and conversely, TED treatments do not address the hyperthyroidism characteristic of GD. By blocking autoantibody activation of the TSHR, ETHY-001 is designed to target the underlying cause of disease and has the potential to address both conditions through a single, mechanism-driven therapy.”

Dr. Kameswaran said the company expects to initiate first-in-human clinical trials of ETHY-001 during the second half of 2026. Preclinical data will be presented at the Endocrine Society’s Annual Meeting (ENDO 2026) in Chicago on June 15.

The company’s leadership team includes Dr. Kameswaran as chief executive officer; Jessica Stromme as chief development officer; Kelly Foster, PhD, as senior vice president of translational medicine; and Stephen Huang, MD, as senior vice president of clinical development.

The Series A financing was co-led by Atlas Venture and Medicxi Ventures, with participation from Nandi Life Sciences and Checkpoint Capital. The subsequent Series B round included all Series A investors and was led by Avoro Capital.