Sensei Biotherapeutics announced that it is reprioritizing its pipeline programs to focus on its product candidates, including its multi-antigenic next generation ImmunoPhage candidate, now referred to as SNS-401-NG, and its monoclonal antibody SNS-VISTA (V-set Immunoglobulin Domain Suppressor of T cell Activation) candidate. With this reallocation of resources, Sensei expects its cash and cash equivalents will be sufficient to fund its operations into the first half of 2024. SNS-301 was developed as a first-generation, bio-engineered, inactivated bacteriophage virus expressing a fragment of the tumor-associated antigen, human aspartate ß-hydroxylase (ASPH), as a fusion protein to the bacteriophage lambda capsid decoration protein, gpD, for patients with locally advanced unresectable or metastatic squamous cell head and neck cancer (SCCHN). To date, 25 patients were enrolled in the Phase 1/2 clinical study and received at least one dose of SNS-301 in combination with pembrolizumab; one patient had a deep and durable partial response (PR) and 8 patients had stable diseases. While encouraged by the safety profile of the SNS-301 single antigen approach, based upon the recent analysis of antigen specific T-cell activation which did not show a significant increase in ASPH-specific T cells, including the one patient who experienced a long-standing and deep PR, and an updated analysis of clinical data, Sensei has decided to reprioritize its pipeline and refocus resources. Sensei anticipates sharing full SNS-301 clinical data and the results of specific B and T cell response data at a future scientific conference. Next-Generation Pipeline Highlights and Upcoming Milestones: Sensei is focused on progressing novel product candidates generated from both its ImmunoPhage platform and Phortress Library™, coupled with its human monoclonal antibody and nanobody platform. Sensei’s Phortress Library of immunophages, derived from antigens found across multiple patient populations and tumor types, enables a personalized, yet off-the-shelf therapeutic option to patients. SNS-401-NG is a first-in-class, multi-antigenic personalized ImmunoPhage candidate being developed in collaboration with the University of Washington. Sensei has designed SNS-401-NG as a personalized product candidate composed of premanufactured Immunophage from Sensei’s Phortress library on an improved and proprietary bacteriophage construct. Sensei intends to initiate IND-enabling studies for this product candidate in the second half of 2022. The first clinical application is directed to the treatment of Merkel Cell Carcinoma (MCC), an aggressive form of skin cancer commonly driven by the Merkel Cell Polyoma Virus. If clinical proof of concept is achieved, Sensei plans to evaluate a broader basket study in patients with head and neck cancer, lung cancer, melanoma, and triple negative breast cancer based on the prevalence of Phortress antigens. VISTA (V-domain Ig suppressor of T cell activation) is an immune checkpoint that inhibits anti-tumor immune responses. VISTA is implicated in PD-1/PD-L1 resistance and therapeutic intervention. VISTA has the potential to be effective as a monotherapy and synergistic with PD-1/PD-L1 inhibition. Sensei has generated potent pH-dependent parental antibodies that block the interaction of VISTA with its receptor, PSGL1, expected to result in a favorable pharmacokinetic (PK) profile and selective activity in the acidic tumor microenvironment – a critical feature of this product candidate, and an important differentiator to other compounds in development targeting VISTA. Sensei plans to present preclinical data from the SNS-VISTA program at a scientific conference in 2021 and to initiate IND-enabling studies by the end of 2021. VSIG4 (V-Set And Immunoglobulin Domain Containing 4) is a potent inhibitor of T cell activity, often overexpressed on macrophages within the tumor microenvironment. Sensei believes that a tumor-selective blocking monoclonal antibody will have potent anti-tumor immune effects. Sensei is extending its approach to developing antibodies with enhanced tumor selective activity to other candidate immune checkpoint targets, and anticipates selecting a product candidate from this program in 2023.