On May 20, 2025, CRISPR Therapeutics, a biopharmaceutical company focused on creating transformative gene-based medicines for serious diseases, and Sirius Therapeutics, a clinical-stage biotech company developing innovative small interfering RNA (siRNA) therapies for global markets, announced a strategic partnership to develop and commercialize novel siRNA therapies. Wilson Sonsini Goodrich & Rosati advised Sirius on patent matters related to the transaction.

Under the terms of the agreement, CRISPR Therapeutics will make an upfront payment of $25 million in cash and $70 million in equity to Sirius. The companies will jointly develop SRSD107—a next-generation, long-acting Factor XI (FXI) siRNA for the treatment of thromboembolic disorders—under a 50-50 cost and profit-sharing structure. CRISPR Therapeutics will lead commercialization in the U.S., while Sirius will be responsible for commercialization in Greater China. Additionally, CRISPR Therapeutics will have the option to nominate up to two siRNA targets for research and development. For each target, CRISPR Therapeutics will fund research and retain opt-in rights to lead clinical development and commercialization. Sirius will be eligible to receive milestone payments, as well as tiered royalties ranging from high-single to low-double digits.

The Wilson Sonsini team that advised Sirius on patent matters related to the transaction was led by Minyoung Shin and included Mike Hostetler, Hee Min Noh, Jen Zeng, and Tiara Wong.

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