Viridian Therapeutics and Kissei Pharmaceutical Ink $70M Deal for Thyroid Eye Disease Drugs in Japan

Viridian Therapeutics has entered into a lucrative licensing agreement with Kissei Pharmaceutical, granting the Japanese company exclusive rights to develop and commercialize two promising thyroid eye disease (TED) drug candidates in Japan. The deal, announced on July 30, 2025, involves an upfront payment of $70 million to Viridian, with the potential for up to $315 million in additional milestone payments.

Deal Highlights and Drug Candidates

The agreement centers around two anti-IGF-1R antibodies: veligrotug and VRDN-003. Both candidates are designed to treat TED, with VRDN-003 boasting potential advantages over veligrotug, including a longer half-life and suitability for subcutaneous administration rather than intravenous delivery.

Viridian CEO Stephen Mahoney described the partnership as the result of "a very competitive partnering process," highlighting the significant interest in these novel TED treatments. Under the terms of the agreement, Kissei will be responsible for all development, regulatory, and commercialization activities and associated costs in Japan.

Market Implications and Competition

This deal positions Kissei as a potential rival to Amgen in the Japanese TED market. Amgen currently sells Tepezza, an anti-IGF-1R antibody, for TED treatment in both the U.S. and Japan. Viridian's candidates aim to improve upon Tepezza's dosing schedule, administration route, and safety profile.

Mutsuo Kanzawa, CEO of Kissei Pharmaceutical, stated that the licensing agreement aligns with the company's strategy to expand its pipeline in rare and intractable diseases. This move could significantly alter the competitive landscape for TED treatments in Japan.

Clinical Progress and Future Outlook

Viridian has advanced both veligrotug and VRDN-003 into phase 3 studies, with promising results thus far. The company aims to file for FDA approval of veligrotug in the second half of 2025, with a potential U.S. launch in 2026. Topline data from phase 3 trials of VRDN-003 are expected in the first half of 2026.

The deal with Kissei strengthens Viridian's financial position, adding to its $636.6 million cash reserves reported at the end of March 2025. This influx of capital is expected to fund operations into the second half of 2027, providing a solid runway for the company's ambitious development and commercialization plans.