Shares of Japanese drugmaker Sumitomo Pharma fell 15.60% 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.
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. The therapies rely on induced pluripotent stem (iPS) cells — adult cells that are reprogrammed back into a stem-cell-like state.
Stem cells are are capable of self-renewal and work as a repair system, replacing damaged cells and maintaining tissues, allowing them to be used in regenerative medicine.
“While the treatment could potentially see widespread use and become a blockbuster in Japan and the US over the long term, we expect almost no profit contribution near term,” said Citigroup Global Markets Japan’s analyst Hidemaru Yamaguchi.
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.
The endorsement comes years after Kyoto University professor Shinya Yamanaka, who later won a Nobel Prize for his stem cell research, first succeeded in generating iPS cells from mice in 2006.
Japan has been striving to develop stem-cell therapies, with Kyoto University’s CiRA, which runs a clinical-grade iPS cell bank, providing researchers access to prepared cells that can be used in trials for a range of conditions.
Sumitomo Pharma develops and markets prescription medicines across multiple therapeutic areas, including neuroscience, oncology and regenerative medicine.
Source: CNBC