Taiho Pharmaceutical Grants Exclusive Rights for PI3Kα Inhibitor Risovalisib (CYH33) to Haihe Biopharma
Taiho Pharmaceutical Co., Ltd. (“Taiho”) and Haihe Biopharma Co., Ltd. (“Haihe”) today announced the signing of an exclusive license agreement granting Taiho the rights to develop, manufacture, and commercialize risovalisib (CYH33), a selective PI3Kα (phosphatidylinositol 3-kinase alpha) inhibitor, in Japan. This agreement marks a significant milestone in the advancement of targeted oncology therapies, particularly for patients with ovarian clear cell carcinoma (OCCC), a rare and difficult-to-treat form of ovarian cancer.
Risovalisib, developed by Haihe, is currently under review in Japan for manufacturing and marketing approval as a treatment for OCCC. Haihe Biopharma K.K., a wholly owned subsidiary of Haihe, submitted a New Drug Application (NDA) in August 2025 for the anticipated indication of “advanced or recurrent ovarian clear cell carcinoma harboring PIK3CA gene mutations that has progressed after chemotherapy.” In recognition of the high unmet medical need, risovalisib received orphan drug designation from Japan’s Ministry of Health, Labour and Welfare in June 2025.
Under the terms of the agreement, Taiho will secure exclusive rights in Japan for risovalisib, encompassing development, manufacturing, and commercialization. Haihe will receive an upfront payment from Taiho, in addition to development and sales milestone payments, as well as royalties based on net sales. This structured collaboration underscores both companies’ commitment to bringing innovative oncology treatments to patients efficiently and responsibly.
Masayuki Kobayashi, President and Representative Director of Taiho, emphasized the strategic significance of the partnership: “We are pleased to announce this collaboration with Haihe, a company with which we have already built a strong working relationship. Risovalisib represents a promising new treatment option for patients with ovarian clear cell carcinoma, and through this partnership, we aim to further contribute to the care and support of patients and healthcare professionals in Japan.”
Dr. Jian Ding, Academician of the Chinese Academy of Engineering and a representative of Haihe, echoed these sentiments: “We are delighted to partner with Taiho, one of Japan’s leading oncology companies, in advancing the development and commercialization of risovalisib. This collaboration has the potential to provide an important therapeutic option for patients with ovarian clear cell carcinoma and other PI3Kα-associated diseases, reflecting our shared commitment to innovation in oncology.”
Risovalisib is a novel, orally bioavailable PI3Kα inhibitor designed to selectively target the alpha isoform of the PI3K family, which plays a key role in tumor cell proliferation and survival. Mutations in the PIK3CA gene are among the most frequently observed genetic alterations in ovarian clear cell carcinoma and other solid tumors. By selectively inhibiting PI3Kα, risovalisib aims to interfere with critical signaling pathways that drive tumor growth while minimizing off-target effects commonly associated with pan-PI3K inhibitors.
The development of risovalisib aligns with Taiho’s strategic focus on oncology and targeted therapies. Japan has a substantial patient population affected by ovarian clear cell carcinoma, which is often resistant to standard chemotherapy. The collaboration with Haihe allows Taiho to leverage its strong local presence, regulatory expertise, and commercialization capabilities to bring this targeted therapy to patients more effectively.
For Haihe, the partnership provides an opportunity to expand the reach of risovalisib into the Japanese market while sharing the development and commercial responsibilities with a trusted partner. Haihe’s innovative research in PI3Kα inhibitors and commitment to addressing high unmet medical needs complement Taiho’s established oncology infrastructure, creating a synergistic model for advancing cutting-edge treatments.
Beyond ovarian clear cell carcinoma, risovalisib may have broader potential across other malignancies and diseases associated with PI3Kα mutations. Ongoing and future studies may explore its utility in combination with other therapies or in additional patient populations, further expanding its clinical impact.
The agreement highlights the increasing importance of strategic alliances in the global biopharmaceutical industry, particularly for precision oncology therapies. By combining Haihe’s scientific expertise in PI3Kα inhibition with Taiho’s established capabilities in drug development, regulatory navigation, and commercialization in Japan, both companies aim to accelerate the delivery of transformative therapies to patients who have limited treatment options.
In conclusion, the exclusive license agreement between Taiho and Haihe represents a significant step forward in the development of targeted cancer therapies in Japan. Risovalisib’s selective mechanism of action, coupled with its orphan drug designation and potential to address a critical unmet need, positions it as a promising addition to the treatment landscape for ovarian clear cell carcinoma. Through this collaboration, Taiho and Haihe are jointly committed to advancing innovative oncology solutions and improving patient outcomes, reinforcing their leadership in the field of precision medicine.
This partnership exemplifies the growing trend of cross-border collaborations in the pharmaceutical sector, where companies leverage complementary strengths to maximize the impact of novel therapies for patients worldwide. As risovalisib progresses through regulatory review and potential market launch, both Taiho and Haihe remain focused on delivering meaningful clinical benefits and supporting the communities of patients affected by ovarian clear cell carcinoma.
