Sumitomo Pharma shares plunge despite greenlight for Parkinson’s treatment
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Shares of Japanese drugmaker Sumitomo Pharma fell over 12% Friday on what appeared to be profit-taking, a day after the government endorsed the company’s iPS cell-based therapy for Parkinson’s and heart disease.
The decision is a milestone in Japan’s years-long effort to cultivate a homegrown sector focused on cutting-edge cellular therapies.
Sumitomo Pharma’s stock, which rose more than 300% in 2025, hit its highest level since 2019 last week amid growing confidence in its Parkinson’s therapy.
Citigroup Global Markets Japan’s analyst Hidemaru Yamaguchi said that while the treatment might see widespread use and become a blockbuster in Japan and the U.S. over the long term, it would hardly contribute to profits in the near term. Sumitomo’s stock has been overheated, and recent gains have been “excessive,” he added.
According to Japan’s Ministry of Health, Labor and Welfare, formal approval will be granted within the next one to two months, NHK reported.
Sumitomo Pharma develops and markets prescription medicines across multiple therapeutic areas, including neuroscience, oncology and regenerative medicine.
