Exelixis Partners with Sairopa to Advance Innovative Cancer Immunotherapy with ADU-1805

### Advancing Cancer Immunotherapy: Sairopa and Exelixis Forge Ahead with Innovative Antibody Development

Sairopa B.V. reaches a significant milestone in its collaboration with Exelixis, Inc. through an exclusive clinical development and option agreement for ADU-1805, a groundbreaking anti-SIRPα antibody designed to enhance the immune system's response to cancer. Under this agreement, Exelixis secures exclusive worldwide licensing rights for ADU-1805 and related antibodies, contingent on the ongoing evaluation of data from Sairopa's Phase 1 clinical studies. This partnership signifies a shared commitment to advancing cancer therapies, with both companies poised to make impactful contributions to the oncology landscape.

The financial backing from Exelixis is substantial, reflecting the confidence in Sairopa's innovative approach. The partnership kicks off with an upfront payment of $40 million, complemented by milestone payments that include $35 million for Investigational New Drug (IND) clearance by the FDA and an additional $35 million linked to clinical development progress. Currently, Sairopa's Phase 1 study is evaluating the safety and pharmacokinetics of ADU-1805 in a multicenter, open-label trial. Patient enrollments are taking place across the U.S. and Europe, exploring both monotherapy and combination therapy with pembrolizumab, a well-known PD-1 inhibitor. This trial is pivotal in determining the potential of ADU-1805 to significantly enhance cancer treatment strategies.

Gurvinder S. Chahal, Sairopa’s Chief Business Officer, underscores the partnership's focus on developing next-generation cancer therapies. In addition to ADU-1805, Sairopa's pipeline includes ADU-1604, an anti-CTLA4 antibody, and a SIRPα-PD-L1 bispecific antibody, showcasing the company's dedication to innovative cancer immunotherapies. With plans for a Phase 2 trial slated for 2025 and an IND filing for the bispecific antibody expected in 2026, Sairopa is strategically positioned to leverage its collaboration with Exelixis, a leader in oncology development, to improve cancer treatment outcomes.

Beyond this collaboration, Sairopa emphasizes its mission to enhance cancer treatment through pioneering research and proprietary platforms. The focus on developing innovative therapies aligns with the growing demand for effective cancer treatments that harness the body’s immune system. As the landscape of cancer immunotherapy evolves, partnerships like that of Sairopa and Exelixis are critical in driving forward the development of next-generation therapies that could alter treatment paradigms for patients worldwide.