Kissei Pharmaceutical is paying Viridian Therapeutics $70 million upfront for Japanese rights to a pair of thyroid eye disease (TED) drug candidates, establishing the drugmaker as a potential rival to Amgen.
The deal, which includes up to $315 million in development, regulatory and commercial milestones, gives Kissei an exclusive license to develop and commercialize veligrotug and VRDN-003 in Japan. Both candidates are anti-IGF-1R antibodies. VRDN-003 has the same binding domain as veligrotug but was designed to have a longer half-life and be suitable for subcutaneous, rather than intravenous, delivery.
Amgen already sells an anti-IGF-1R antibody, Tepezza, for use in TED patients in markets including the U.S. and Japan. Viridian has identified opportunities to improve on Tepezza’s dosing schedule, route of administration and safety profile, leading it to advance veligrotug and VRDN-003 into phase 3 studies.
Viridian CEO Stephen Mahoney discussed ex-U.S. plans for the drug candidates at a Goldman Sachs event in June, telling analysts that the company was keeping all its options open when considering when and how to commercialize the antibodies in markets including Europe and Japan. Wednesday, Mahoney said in a statement that the Kissei deal was the result of “a very competitive partnering process.”
Kissei is licensing the candidates to expand its pipeline in rare and intractable diseases, the company’s CEO Mutsuo Kanzawa said in a statement. The Japanese drugmaker will be responsible for development, regulatory and commercialization activities, as well as the associated costs, in its home country.
Striking the deal strengthens Viridian’s cash position, which stood at $636.6 million at the end of March. The biotech predicted the March figure would fund operations into the second half of 2027. Viridian is aiming to file for FDA approval of veligrotug in the second half of 2025 and launch in the U.S. in 2026. Top-line data from phase 3 trials of VRDN-003 are due in the first half of next year.