On March 17, 2025, Taiho Pharmaceutical Co., Ltd., an R&D-driven specialty pharmaceutical company focusing on the fields of oncology and immune-related diseases, and Araris Biotech AG, a Swiss biotechnology company developing next-generation antibody drug conjugates (ADCs), announced that they have entered into a definitive agreement pursuant to which Taiho Pharmaceutical will acquire Araris. Under the terms of the agreement, Taiho Pharmaceutical will pay $400 million at closing, with the potential for additional milestone payments of up to $740 million. The acquisition, which is expected to be completed in the first half of 2025, follows a research collaboration between Taiho Pharmaceutical and Araris signed in November 2023. Wilson Sonsini Goodrich & Rosati advised Taiho Pharmaceutical on the acquisition.

Araris is a spin-off company of the Paul-Scherrer-Institute in Switzerland and is pioneering the development of best-in-class ADCs with superior design, high linker solubility, and simple manufacturing that address the shortcomings of current generation ADCs. Taiho Pharmaceutical, in addition to antimetabolites, has established and created novel drugs through its proprietary small molecule drug discovery platform, Cysteinomix, enhancing cancer treatment and contributing to patient care. By acquiring Araris' innovative ADC drug discovery technology platform, Taiho Pharmaceutical will further expand its ongoing development portfolio in the field of oncology.

The Wilson Sonsini team that advised Taiho Pharmaceutical on the transaction included Miranda Biven, Jason Breen, Nellie Brutocao, and Ken Clark.

For more information, please see the companies’ joint news release. Additional coverage is available on Fierce Biotech and BioSpace.