Taiho Pharma and Haihe Biopharma Form Exclusive Japanese Partnership for PI3Kα Inhibitor Risovalisib
Taiho Pharmaceutical Co., Ltd. (“Taiho”) and Haihe Biopharma Co., Ltd. (“Haihe”) today announced the signing of an exclusive license agreement for the development, manufacturing, and commercialization of risovalisib (development code: CYH33), a selective PI3Kα (phosphatidylinositol 3-kinase alpha) inhibitor. The agreement grants Taiho exclusive rights in Japan to further develop and market the therapy, while Haihe will receive an upfront payment, milestone-based development and sales payments, and royalties tied to the product’s sales revenue.
Risovalisib represents a novel approach in the treatment of ovarian clear cell carcinoma (OCCC), a rare and aggressive subtype of ovarian cancer. The drug, developed by Haihe, is currently under regulatory review in Japan, with Haihe Biopharma K.K., a wholly owned Japanese subsidiary of Haihe, having submitted a New Drug Application (NDA) in August 2025. The application seeks approval for treating “advanced or recurrent ovarian clear cell carcinoma harboring PIK3CA gene mutations that has progressed after chemotherapy.” Notably, risovalisib received orphan drug designation from Japan’s Ministry of Health, Labour and Welfare in June 2025, reflecting its potential to address a serious unmet medical need in a rare patient population.
The collaboration leverages the strengths of both organizations. Taiho, a leading oncology company in Japan, brings extensive experience in clinical development, regulatory strategy, and commercialization within the Japanese healthcare system. Haihe contributes its innovative research and early-stage development capabilities, particularly in targeted cancer therapies. By combining theseTaiho Pharma complementary capabilities, the partnership aims to accelerate patient access to a potentially life-changing treatment for OCCC.
Masayuki Kobayashi, President and Representative Director of Taiho, expressed optimism about the collaboration, stating, “We are pleased to announce that we will be entering into this partnership with Haihe, with whom we have already built a strong collaborative relationship. Through risovalisib, a new treatment option for patients with ovarian clear cell carcinoma, we will continue to work together with Haihe to further contribute to patients and healthcare professionals.” Kobayashi emphasized the shared commitment of both companies to advance innovative therapies that address critical unmet needs in oncology.
Dr. Jian Ding, Academician of theTaiho Pharma Chinese Academy of Engineering and a representative of Haihe, also commented on the partnership, highlighting the potential benefits for patients in Japan. “We are pleased to announce that we are entering into a partnership with Taiho, one of the leading oncology companies in Japan, regarding the PI3Kα inhibitor risovalisib. We hope our collaboration will be able to provide a promising treatment option for patients with ovarian clear cell carcinoma and other PI3Kα-associated diseases,” Dr. Ding stated. This collaboration underscores Haihe’s ongoing strategy of forming alliances with established pharmaceutical companies to expand the reach of its pipeline therapies and maximize patient impact.
Ovarian clear cell carcinoma is characterized by its resistance to standard chemotherapy and poor prognosis compared with other ovarian cancer subtypes. Approximately 5–10% of ovarian cancers in Japan are clear cell carcinomas, and a significant proportion of these cases are associated with mutations in the PIK3CA gene. The PI3Kα pathway plays a key role in cell proliferation, survival, and metabolism, making it a highly relevant target for precision oncology. By selectively inhibiting PI3Kα, risovalisib has the potential to interfere with cancer growth while minimizing off-target effects commonly associated with broader PI3K inhibitors.
The license agreement is expected to accelerate the clinical development and commercialization of risovalisib in Japan, potentially providing physicians and patients with a much-needed therapeutic option in a disease space that has seen limited advancement. Under the agreement, Taiho will manage the regulatory submission process, clinical trial execution, Taiho Pharma and post-approval commercialization, ensuring that risovalisib is effectively positioned for patient access once approved. Haihe, meanwhile, will continue to oversee ongoing research and development activities globally, including studies targeting other PI3Kα-associated cancers.
This strategic alliance is part of a broader trend in the oncology sector, where biopharmaceutical companies increasingly partner across borders to combine innovative drug discovery with local expertise in regulatory and commercial execution. By leveraging Taiho’s established presence in Japan, Haihe aims to maximize the clinical and commercial potential of risovalisib, while Taiho benefits from access to an advanced oncology asset targeting a significant unmet need.
In summary, the exclusive license agreement between Taiho Pharmaceutical and Haihe Biopharma represents a significant step forward in the development of targeted therapies for ovarian clear cell carcinoma. With Taiho’s robust development and commercialization capabilities in Japan and Haihe’s innovative approach to PI3Kα inhibition, risovalisib has the potential to offer a new treatment paradigm for patients with limited options. As regulatory review progresses, both companies are positioned to deliver a therapy that could meaningfully improve outcomes for patients facing this challenging disease.
