Full Dose Expansion Data for Solnerstotug in PD-(L)1 Resistant Tumors October 20, 2025 Presenters: Dr. Kyriakos Papadopoulos Co-Director of Clinical Research START, San Antonio Principal Investigator for Ph1 trial of Solnerstotug John Celebi Chief Executive Officer Ron Weitzman Chief Medical Officer Disclaimer This presentation has been prepared by Sensei Biotherapeutics, Inc. (the "Company," "we," "us") and is made for informational purposes only. The information set forth herein does not purport to be com ...

Summary of Sensei Biotherapeutics (SNSE) FY Conference - September 05, 2025 Company Overview - **Company**: Sensei Biotherapeutics - **Industry**: Biotechnology - **Focus**: Developing conditionally active antibodies for cancer using the Tumor Microenvironment Activated Biologics (TMAb) platform [1] Core Points and Arguments 1. **Defining Year**: 2025 is highlighted as a pivotal year for Sensei Biotherapeutics, transitioning from early promise to more mature efficacy signals, with phase one to dose expansion results expected at the ESMO Congress in October [2] 2. **Lead Program - SylvesterTOG**: - Positioned as the first credible VISTA-targeted therapy, aiming to address issues that previously hindered VISTA-focused antibodies [2] - Designed to selectively bind in the acidic tumor microenvironment, minimizing toxicity and improving pharmacokinetics [3] 3. **Market Opportunity**: - The PD-L1 therapy market is valued at $50 billion, with VISTA expressed in most solid tumors, indicating a significant potential for SylvesterTOG [3] - The approach aims to open a new checkpoint pathway that could rival PD-L1 therapies [3] 4. **Collaboration with Regeneron**: Evaluating SylvesterTOG in combination with Regeneron's PD-1 inhibitor, Libtayo, across various tumors, showcasing the innovative approach and recognition of VISTA's role in immunotherapy resistance [4] 5. **Safety and Efficacy**: - SylvesterTOG has shown a favorable safety profile with no dose-limiting toxicities and manageable cytokine release events, contrasting with earlier VISTA programs that faced severe issues [5] - The trial focused on "hot tumors," with historical response rates for PD-1 rechallenge being in the single digits, yet SylvesterTOG demonstrated remarkable activity [6][7] 6. **Durability of Response**: - Emphasis on the importance of durable responses in immunotherapy, with several patients showing long-term benefits from SylvesterTOG [8][9] - Full phase one to dose expansion data, including six-month progression-free survival (PFS) metrics, will be presented at ESMO [10] 7. **Safety Profile in Expansion Cohort**: Most adverse events were grade one or two, with low-grade cytokine release, indicating a well-tolerated treatment [11] 8. **Future Plans**: - Plans to initiate phase two studies in 2026, with multiple trials aligned with unmet medical needs and commercial potential [11] - Financially positioned with a cash runway into 2026 to support upcoming milestones [12] Other Important Content - **Recognition at ESMO**: The data will be featured in a mini oral session at ESMO, marking a significant recognition of the work being done on VISTA as a therapeutic target [10] - **Investor Opportunity**: Sensei Biotherapeutics presents a unique investment opportunity in the first successful unlocking of VISTA's myeloid biology, which could reshape the immuno-oncology landscape [12]