VSIG4

- Once every 3-week dosing of SNS-101 demonstrates initial signs of promising clinical activity - - Pharmacokinetic and safety profile validate conditionally active approach - - Investor webcast to be held on Monday, June 3 at 8:00 a.m. ET - May 23, 2024 -- Sensei Biotherapeutics, Inc. (Nasdaq: SNSE), a clinical stage immuno-oncology company focused on the discovery and development of next-generation therapeutics for cancer patients, today reported encouraging clinical data from the dose escalation portion of its Phase 1/2 trial of SNS-101, a conditionally active, human monoclonal antibody targeting the immune checkpoint VISTA (V-domain Ig suppressor of T cell activation). “I am pleased that SNS-101 has been well-tolerated in the study, reaching its highest planned dose level with no dose limiting toxicities and demonstrating its potential to successfully overcome the prior challenges of VISTA-targeted programs,” said Dr. Shiraj Sen, Medical Oncologist and Director of Clinical Research at NEXT Oncology, Dallas, and a principal investigator for the SNS-101 study. “The data show encouraging signs of clinical activity in a heterogeneous population of patients with advanced solid tumors, where you typically wouldn’t expect to see clinical responses, especially in microsatellite stable colorectal and endometrial tumors. There is a continued unmet need for patient populations that have become resistant or don’t respond to current immunotherapy treatment options. I look forward to continuing to evaluate its progress.” The dose escalation portion of the Phase 1/2 clinical trial is designed to evaluate the safety, tolerability, pharmacokinetics, pharmacodynamics, and efficacy of SNS-101. This study assesses SNS-101 both as monotherapy and in combination with Regeneron’s PD-1 inhibitor Libtayo® (cemiplimab, 350 mg), in patients with advanced solid tumors with primary (unfavorable candidates for immunotherapy) or acquired PD-1 therapy resistance (progressed on prior anti-PD-1 therapy). A total of 34 patients received SNS-101 once every 3 weeks, with 16 patients in the monotherapy arm and 18 patients in the combination arm. The majority of patients (85%) had a tumor type that is typically unresponsive to PD-1 monotherapy (“cold” tumors). As of the April 30, 2024 data cutoff, SNS-101 demonstrated preliminary evidence of promising clinical activity in multiple tumor types, including: One microsatellite stable (MSS) endometrial cancer patient that received SNS-101 plus cemiplimab had a confirmed partial response (59% decrease) and remains on study at 30+ weeks. MSS endometrial cancer has been previously shown to have a low response rate to monotherapy immunotherapy treatments. One MSS colorectal cancer (CRC) patient that received SNS-101 plus cemiplimab remained on study for 18 weeks and had tumor regression of 27%. MSS CRC has been previously shown to be unresponsive to PD-1 treatments. One pembrolizumab-resistant renal cell carcinoma patient that received SNS-101 plus cemiplimab remained on study for 12 weeks and had tumor regression of 18%. One pembrolizumab-resistant human papillomavirus (HPV)+ head and neck cancer patient that received SNS-101 as monotherapy remained on study for 12 weeks and had tumor regression of 17%. These clinical data are consistent with preclinical studies suggesting therapeutically relevant clinical doses of SNS-101 at 3mg/kg or higher. Additionally, preliminary flow-based pharmacodynamic analysis showed dose-dependent changes in specific T-cell populations suggesting SNS-101 may be having a pharmacological effect on T-cell subsets. SNS-101 demonstrated a potentially best-in-class pharmacokinetic (PK) profile with linear elimination kinetics and dose-proportional increases in exposure, supporting once every three week dosing. The data are consistent with lack of target-mediated drug disposition (TMDD), which has been observed in non-conditionally active anti-VISTA antibodies. SNS-101 was well tolerated alone and in combination with cemiplimab, with no dose-limiting toxicities observed. The majority of AEs were Grade 1 or 2 in severity. Two patients experienced Grade 1 cytokine release syndrome (CRS), one in monotherapy and one in combination, both at the highest dose of SNS-101. Both cases were mild and manageable, demonstrating that SNS-101 has the potential to overcome a key hurdle that hindered first-generation VISTA-targeting approaches. Four patients in the combination cohort experienced immune-mediated events. There were also no significant changes to key inflammatory cytokine levels, including interferon gamma, interleukin-6, interleukin-10, interleukin-8, TNF-alpha, and CCL5-RANTES, across cohorts. “The dose escalation portion of the Phase 1/2 trial of SNS-101 answers the critical question of whether a pH-selective approach can overcome the previous hurdles associated with targeting VISTA, which included severe safety and PK issues. We believe the topline data presented today marks an important milestone and validates the mechanism of action by demonstrating the potentially best-in-class PK and a well-tolerated safety profile of SNS-101 at therapeutically relevant dose levels,” said Ron Weitzman, Chief Medical Officer of Sensei Bio. “We saw promising clinical activity primarily in tumor types that don’t typically respond to PD-1 monotherapy and look forward to progressing through the expansion phase of the study.” Patient enrollment is advancing in the dose expansion portion of the Phase 1/2 study. The Company expects to report initial data from the dose expansion cohorts and to hold an end-of-Phase 1 meeting with the FDA by the end of 2024. The data will be presented in a poster presentation entitled “Initial results from a first-in-human phase 1 study of SNS-101 (pH-selective anti-VISTA antibody) alone or in combination with cemiplimab in patients with advanced solid tumors,” on June 1, 2024, at the 2024 American Society of Clinical Oncology (ASCO) Annual Meeting being held in Chicago, IL. The poster will be available on the Sensei website at the start of the poster presentation. Sensei Biotherapeutics (Nasdaq: SNSE) is a clinical stage immuno-oncology company focused on the discovery and development of next-generation therapeutics for cancer patients. Through its TMAb™ (Tumor Microenvironment Activated biologics) platform, Sensei develops conditionally active therapeutics designed to disable immunosuppressive signals or activate immunostimulatory signals selectively in the tumor microenvironment. Sensei’s lead investigational candidate is SNS-101, a conditionally active antibody designed to block the V-domain Ig suppressor of T cell activation (VISTA) checkpoint selectively within the low pH tumor microenvironment, where VISTA acts as a suppressor of T cells by binding the receptor PSGL-1. The company is also developing SNS-102, a conditionally active monoclonal antibody targeting V-Set and Immunoglobulin Domain Containing 4 (VSIG-4); SNS-103, a conditionally active monoclonal antibody targeting ecto-nucleoside triphosphate diphosphohydrolase-1 (ENTPDase1), also known as CD39; and SNS-201, a conditionally active VISTAxCD28 bispecific antibody consisting of a CD28 agonist arm and a pH-sensitive anti-VISTA arm. For more information, please visit www.senseibio.com, and follow the company on X @SenseiBio and LinkedIn. The content above comes from the network. if any infringement, please contact us to modify.

- Completed SNS-101 monotherapy and combination dose escalation through 15mg/kg with no dose limiting toxicities - - Company to present topline clinical data from the SNS-101 Phase 1 dose escalation study at the 2024 ASCO Annual Meeting - - Enrollment in the dose expansion portion of the clinical study advancing - - Strong balance sheet with cash runway into fourth quarter of 2025 - BOSTON, May 09, 2024 (GLOBE NEWSWIRE) -- Sensei Biotherapeutics, Inc. (Nasdaq: SNSE), a clinical stage immuno-oncology company focused on the discovery and development of next-generation therapeutics for cancer patients, today reported financial results for the first quarter ended March 31, 2024, and provided corporate updates. “Building upon our initial data for SNS-101, which we believe support a favorable and potentially best-in-class clinical safety and PK profile, we now look forward to sharing topline dose escalation data at ASCO in June and initial dose expansion data in the fourth quarter of this year,” said John Celebi, President and Chief Executive Officer. “Looking ahead, we are squarely focused on advancing patient enrollment in the dose expansion cohorts, which are intended to generate additional supportive data and optimize the Phase 2 trial design for SNS-101. With cash runway into the fourth quarter of 2025, we believe we are in a strong position to build on both our clinical momentum on behalf of the patients we aim to serve and our scientific advances, as illustrated by our recent publication in Nature Communications.” Highlights and Milestones SNS-101 SNS-101 is a conditionally active antibody harnessing the acidic tumor microenvironment to selectively target the immune checkpoint VISTA (V-domain Ig suppressor of T cell activation). VISTA is implicated in numerous cancer indications and its expression correlates with low survival rates. Sensei is conducting a multi-center Phase 1/2 clinical trial to evaluate the safety, tolerability, pharmacokinetics, pharmacodynamics, and efficacy of SNS-101 as both a monotherapy and in combination with Regeneron’s PD-1 inhibitor Libtayo® (cemiplimab) in patients with advanced solid tumors. Recent updates include: Sensei has completed enrollment in the dose escalation portion of the Phase 1/2 clinical trial of SNS-101, enrolling 16 patients in the monotherapy arm and 18 patients in the combination arm. In the monotherapy dose escalation arm, patients have cleared all planned dosing cohorts of 0.3, 1, 3, 10, and 15 mg/kg.In the combination dose escalation arm, patients have cleared all planned dosing cohorts of 3, 10, and 15 mg/kg of SNS-101 plus Libtayo.There have been no dose limiting toxicities (DLT) observed across both the monotherapy and the combination arms.Sensei will present topline clinical data from the monotherapy and combination dose escalation portion of its Phase 1/2 trial of SNS-101 in a poster presentation at the upcoming 2024 American Society of Clinical Oncology (ASCO) Annual Meeting taking place in Chicago, IL, from May 31 – June 4, 2024. Title: Initial results from a first-in-human phase 1 study of SNS-101 (pH-selective anti-VISTA antibody) alone or in combination with cemiplimab in patients with advanced solid tumorsPresenter: Dr. Shiraj SenSession Type: Poster SessionSession Title: Developmental Therapeutics—ImmunotherapyDate and Time: Saturday, June 1, 2024, at 9:00 a.m. – 12:00 p.m. CDTAbstract Number: 2600 Patient enrollment is ongoing for both the monotherapy and combination dose expansion arms. In the monotherapy dose expansion arm, Sensei is enrolling patients with microsatellite stable (MSS) colorectal cancer (CRC) at a dose level of 15 mg/kg.In the combination dose expansion arm, Sensei is enrolling patients with MSS CRC, Head and Neck (H&N) cancer, non-small cell lung cancer (NSCLC), and melanoma at a dose level of 15 mg/kg plus Libtayo.The solid tumor types were selected to focus the cancer indications on a basket of more commonly occurring histologies, including both “hot” (NSCLC, H&N, Melanoma) and “cold” (CRC) tumors where the company believes SNS-101 has potential to provide clinical benefit based on VISTA biology and supporting preclinical data. Additional tumor types and doses may be considered for both the monotherapy and combination expansion arms.The Company expects to report initial data from the dose expansion cohorts and hold an end-of-Phase 1 meeting with the FDA by the end of 2024. In April 2024, Sensei published a peer-reviewed research paper in Nature Communications describing the mechanism of action of SNS-101 selectively targeting the active form of VISTA within the tumor microenvironment.In March 2024, the company presented SNS-101 data at Keystone Symposia’s Cancer Immunotherapy: Beyond Immune Checkpoint Blockade and Overcoming Resistance.In February, Sensei presented at the 10th Annual Immuno-Oncology 360 Conference (IO360). Corporate Updates In January 2024, Sensei announced the appointment of Ron Weitzman, M.D., F.A.C.P., as part-time Chief Medical Officer.In January 2024, Sensei announced a realignment of its resources to fully support the Phase 1/2 clinical trial of SNS-101. As a result, Sensei has paused IND-enabling work on its preclinical-stage TMAb programs, including SNS-102 (VSIG4), SNS-103 (CD39) and SNS-201 (VISTAxCD28). Preclinical work to characterize selected lead antibodies, including their mechanisms of action, and target biology is expected to continue throughout 2024.As a result of this realignment of resources Sensei’s cash runway now extends into the fourth quarter of 2025. First Quarter 2024 Financial Results Cash Position: Cash, cash equivalents and marketable securities were $58.1 million as of March 31, 2024, as compared to $65.8 million as of December 31, 2023. The decrease is due to cash used to fund operations. Sensei expects its current cash balance to fund operations into the fourth quarter of 2025. Research and Development (R&D) Expenses: R&D expenses were $4.9 million for the quarter ended March 31, 2024, compared to $5.2 million for the quarter ended March 31, 2023. The decrease in R&D expenses was primarily attributable to lower manufacturing-related expenses and lower costs related to preclinical research, primarily offset by higher expenses associated with clinical trials. General and Administrative (G&A) Expenses: G&A expenses were $3.8 million for the quarter ended March 31, 2024, compared to $5.8 million for the quarter ended March 31, 2023. The decrease in G&A expense was primarily attributable to decreased cost for external professional services. Net Loss: Net loss was $8.0 million for the quarter ended March 31, 2024, compared to $10.2 million for the quarter ended March 31, 2023. About Sensei BiotherapeuticsSensei Biotherapeutics (Nasdaq: SNSE) is a clinical stage immuno-oncology company focused on the discovery and development of next-generation therapeutics for cancer patients. Through its TMAb™ (Tumor Microenvironment Activated biologics) platform, Sensei develops conditionally active therapeutics designed to disable immunosuppressive signals or activate immunostimulatory signals selectively in the tumor microenvironment to unleash T cells against tumors. Sensei’s lead product candidate is SNS-101, a conditionally active antibody designed to block the V-domain Ig suppressor of T cell activation (VISTA) checkpoint selectively within the low pH tumor microenvironment, where VISTA acts as a suppressor of T cells by binding the receptor PSGL-1. The company is also developing SNS-102, a conditionally active monoclonal antibody targeting V-Set and Immunoglobulin Domain Containing 4 (VSIG-4); SNS-103, a conditionally active monoclonal antibody targeting ecto-nucleoside triphosphate diphosphohydrolase-1 (ENTPDase1), also known as CD39; and SNS-201, a conditionally active VISTAxCD28 bispecific antibody consisting of a CD28 agonist arm and a pH-sensitive anti-VISTA arm. For more information, please visit www.senseibio.com, and follow the company on X @SenseiBio and LinkedIn. Condensed Statements of Operations (Unaudited, in thousands except share and per share data) Three Months Ended March 31, 2024 2023 Operating expenses: Research and development $4,917 $5,204 General and administrative 3,813 5,804 Total operating expenses 8,730 11,008 Loss from operations (8,730) (11,008)Total other income 738 831 Net loss (7,992) (10,177)Net loss attributable to common stockholders (7,992) (10,177)Net loss per share, basic and diluted $(0.32) $(0.33)Weighted-average common shares outstanding, basic and diluted 25,049,111 30,866,087 Selected Condensed Balance Sheet Data (Unaudited, in thousands) March 31, 2024 December 31, 2023 Cash and cash equivalents $10,956 $13,011 Marketable securities 47,125 52,746 Total assets 66,695 74,374 Total liabilities 8,221 9,479 Total stockholders’ equity 58,474 64,895 Cautionary Note Regarding Forward-Looking StatementsAny statements contained in this press release that do not describe historical facts may constitute forward-looking statements as that term is defined in the Private Securities Litigation Reform Act of 1995. These statements may be identified by words and phrases such as “believe”, “designed to,” “expect”, “may”, “plan”, “potential”, “will”, and similar expressions, and are based on Sensei’s current beliefs and expectations. These forward-looking statements include expectations regarding the development and potential therapeutic benefits of Sensei’s product candidates, the timing of Sensei’s Phase 1/2 clinical trial of SNS-101, including reporting of data therefrom, the timing of preclinical R&D activities, and its belief that its existing cash and cash equivalents will be sufficient to fund its operations into the fourth quarter of 2025. These statements involve risks and uncertainties that could cause actual results to differ materially from those reflected in such statements. Risks and uncertainties that may cause actual results to differ materially include uncertainties inherent in the development of therapeutic product candidates, such as the risk that any one or more of Sensei’s product candidates will not be successfully developed or commercialized; the risk of delay or cessation of any planned clinical trials of Sensei’s product candidates; the risk that prior results, such as signals of safety, activity or durability of effect, observed from preclinical trials, will not be replicated or will not continue in ongoing or future studies or clinical trials involving Sensei’s product candidates; the risk that Sensei’s product candidates or procedures in connection with the administration thereof will not have the safety or efficacy profile that Sensei anticipates; risks associated with Sensei’s dependence on third-party suppliers and manufacturers, including sole source suppliers, over which Sensei may not always have full control; risks regarding the accuracy of Sensei’s estimates of expenses, capital requirements and needs for additional financing; and other risks and uncertainties that are described in Sensei’s Quarterly Report on Form 10-Q filed with the U.S. Securities and Exchange Commission (SEC) on May 9, 2024 and Sensei’s other Periodic Reports filed with the SEC. Any forward-looking statements speak only as of the date of this press release and are based on information available to Sensei as of the date of this release, and Sensei assumes no obligation to, and does not intend to, update any forward-looking statements, whether as a result of new information, future events or otherwise. Investor Contact:Michael BiegaSenior Director, Investor RelationsSensei Biotherapeuticsmbiega@senseibio.com Media Contact: Joyce Allaire LifeSci Advisors Jallaire@lifesciadvisors.com

- Completed SNS-101 monotherapy dose escalation through 15 mg/kg with no dose limiting toxicities - - Expands patient cohort in specific tumor types - - Multiple clinical milestones expected in 2024 - - Strong balance sheet with cash runway extended into the fourth quarter of 2025 - BOSTON, Jan. 04, 2024 (GLOBE NEWSWIRE) -- Sensei Bio, Inc. (Nasdaq: SNSE), a clinical stage immuno-oncology company focused on the discovery and development of next-generation therapeutics for cancer patients, today provided corporate updates on its research and development programs and upcoming milestones. “In 2023, we significantly advanced our lead clinical asset while prudently maintaining our strong balance sheet,” said John Celebi, President and Chief Executive Officer. “We believe SNS-101, which has demonstrated potentially best-in-class pharmacokinetics and tolerability at clinical doses far beyond other VISTA-targeted immunotherapies, has strong potential as a transformative option in multiple cancer indications. Given the favorable data thus far, we are expanding the SNS-101 Phase 1/2 clinical trial to include additional patients in a more focused set of indications as an intermediate stage to further optimize the Phase 2 study design with additional patient data while we prepare for an anticipated end of Phase 1 meeting with FDA by Q4 2024. As a result, we are dedicating additional resources to support this expanded clinical program while pausing the IND-enabling studies originally planned for our next TMAb product candidate. We expect these adjustments to extend our cash runway into the fourth quarter of 2025.” Highlights and Milestones SNS-101 SNS-101 is a conditionally active antibody harnessing the acidic tumor microenvironment to target the immune checkpoint VISTA (V-domain Ig suppressor of T cell activation). VISTA is implicated in numerous cancer indications and its expression correlates with low survival rates. Sensei is conducting a multi-center Phase 1/2 clinical trial to evaluate the safety, tolerability, pharmacokinetics, pharmacodynamics, and efficacy of SNS-101 as both a monotherapy and in combination with Regeneron’s PD-1 inhibitor Libtayo® (cemiplimab) in patients with advanced solid tumors. Recent updates include: As of January 2, 2024: A total of 25 patients have been treated with SNS-101 across various dose levels, with 16 patients in the monotherapy arm and nine patients in the combination arm. There have been no dose limiting toxicities (DLT) observed across both the monotherapy arm and the combination arm. In the monotherapy dose escalation arm, patients have cleared all planned dosing cohorts of 0.3, 1, 3, 10 and 15 mg/kg. In the combination dose escalation arm, six patients have been enrolled in the first cohort and have cleared the DLT period at a dose level of 3.0 mg/kg SNS-101 + Libtayo. The second cohort at a dose level of 10.0 mg/kg SNS-101 + Libtayo has been enrolled and is pending clearance of the DLT period as determined by the study safety monitoring committee. Following completion of dose escalation and prior to initiating the Phase 2 portion, the Company plans to enroll up to 40 additional patients in both monotherapy and in combination with Libtayo in specific tumor types to further optimize the design of the Phase 2 trial. In the monotherapy dose expansion arm, Sensei plans to enroll up to 10 patients with microsatellite stable (MSS) colorectal cancer (CRC) at a dose level of 15 mg/kg. In the combination dose expansion arm, Sensei plans to enroll up to 30 patients with MSS CRC, head and neck cancer (H&N), non-small cell lung cancer (NSCLC), and melanoma. The dose level will be determined following completion of the combination dose escalation phase of the study. The solid tumor types were selected to focus the cancer indications on a basket of more commonly occurring histologies, including both “hot” (NSCLC, H&N, Melanoma) and “cold” (CRC) tumors where we believe SNS-101 has potential to provide clinical benefit based on VISTA biology and supporting preclinical data. All patients with “hot” tumors enrolling into the expansion arm are expected to have been previously treated with a PD1/L1 checkpoint inhibitor. Additional tumor types and doses may be considered for both the monotherapy and combination expansion arms. Sensei expects to open enrollment in the monotherapy expansion arm later this month. The combination expansion arm will begin following completion of the combination dose escalation phase of this study. Anticipated milestones for the SNS-101 Phase 1/2 clinical trial include: Initial safety and pharmacokinetic data for the combination dose escalation arm of SNS-101 and Libtayo in Q1 2024 Topline data for the SNS-101 monotherapy dose escalation arm in Q2 2024 Topline data for the combination dose escalation arm of SNS-101 and Libtayo in Q3 2024 Initial data for the SNS-101 dose expansion cohorts by the end of 2024 Additional Corporate Updates Sensei announces that Ron Weitzman, M.D., F.A.C.P., has joined Sensei as part-time Chief Medical Officer. Dr. Weitzman joined Sensei as a consultant in August 2022 and has been instrumental in the design and implementation of the ongoing Phase 1/2 clinical trial. Dr. Weitzman brings over 25 years experience leading oncology clinical studies ranging from early to late-stage clinical development, including a pivotal study for cabozantanib that led to its FDA approval. Dr. Weitzman has held leadership roles at various global biopharmaceutical companies, including Exelixis, Genentech and Novartis, and has served as a consulting CMO to various biotechnology companies for nearly a decade. Dr Weitzman is board-certified by the American Board of Internal Medicine in Medical Oncology and is an active member of the American College of Physicians. Sensei has decided to realign its resources to fully support the Phase 1/2 clinical trial of SNS-101. As a result, Sensei will pause IND-enabling work on its preclinical-stage TMAb programs, including SNS-102 (VSIG4), SNS-103 (CD39) and SNS-201 (VISTAxCD28). During this time, preclinical work to characterize selected lead antibodies, including their mechanisms of action, and target biology is expected continue. In 2023, Sensei selected lead candidates for both SNS-102 and SNS-201. SNS-102 is a conditionally active antibody targeting VSIG4 that is 585-fold more selective for VSIG4 at low pH conditions. SNS-201 is a bispecific antibody incorporating a CD28 agonist arm and a pH-sensitive anti-VISTA arm designed to conditionally activate CD28 under low pH conditions, such as those found in the tumor microenvironment, leading to T cell activation in the tumor while minimizing off-tumor toxicity. This realignment of resources is expected to extend cash runway into the fourth quarter of 2025. About Sensei Biotherapeutics Sensei Biotherapeutics (Nasdaq: SNSE) is a clinical stage immuno-oncology company focused on the discovery and development of next-generation therapeutics for cancer patients. Through its TMAb™ (Tumor Microenvironment Activated biologics) platform, Sensei develops conditionally active therapeutics designed to disable immunosuppressive signals or activate immunostimulatory signals selectively in the tumor microenvironment. Sensei’s lead investigational candidate is SNS-101, a conditionally active antibody designed to block the V-domain Ig suppressor of T cell activation (VISTA) checkpoint selectively within the low pH tumor microenvironment, where VISTA acts as a suppressor of T cells by binding the receptor PSGL-1. The company is also developing SNS-102, a conditionally active monoclonal antibody targeting V-Set and Immunoglobulin Domain Containing 4 (VSIG-4); SNS-103, a conditionally active monoclonal antibody targeting ecto-nucleoside triphosphate diphosphohydrolase-1 (ENTPDase1), also known as CD39; and SNS-201, a conditionally active VISTAxCD28 bispecific antibody consisting of a CD28 agonist arm and a pH-sensitive anti-VISTA arm. For more information, please visit , and follow the company on Twitter @SenseiBio and LinkedIn. Cautionary Note Regarding Forward-Looking Statements Any statements contained in this press release that do not describe historical facts may constitute forward-looking statements as that term is defined in the Private Securities Litigation Reform Act of 1995. These statements may be identified by words and phrases such as “believe”, “designed to,” “expect”, “may”, “plan”, “potential”, “will”, and similar expressions, and are based on Sensei’s current beliefs and expectations. These forward-looking statements include expectations regarding the development and potential therapeutic benefits of Sensei’s product candidates, the timing of Sensei’s Phase 1/2 clinical trial of SNS-101, including reporting of data therefrom, the expansion of the Phase 1 clinical trial to include additional patients with specific tumor types, the expected timing of an end of Phase 1 meeting with the FDA for SNS-101, preclinical activities related to the Company’s preclinical TMAb product candidates, and its belief that its existing cash and cash equivalents will be sufficient to fund its operations at least into the fourth quarter of 2025. These statements involve risks and uncertainties that could cause actual results to differ materially from those reflected in such statements. Risks and uncertainties that may cause actual results to differ materially include uncertainties inherent in the development of therapeutic product candidates, such as the risk that any one or more of Sensei’s product candidates will not be successfully developed or commercialized; the risk of delay or cessation of any planned clinical trials of Sensei’s product candidates; the risk that prior results, such as signals of safety, activity or durability of effect, observed from preclinical trials and early results from the clinical trial of SNS-101, will not be replicated or will not continue in ongoing or future studies or clinical trials involving Sensei’s product candidates, including SNS-101; the risk that Sensei’s product candidates or procedures in connection with the administration thereof will not have the safety or efficacy pro Sensei anticipates; risks associated with Sensei’s dependence on third-party suppliers and manufacturers, including sole source suppliers, over which Sensei may not always have full control; risks regarding the accuracy of Sensei’s estimates of expenses, capital requirements and needs for additional financing; and other risks and uncertainties that are described in Sensei’s Quarterly Report on Form 10-Q filed with the U.S. Securities and Exchange Commission (SEC) on or about November 7, 2023 and Sensei’s other Periodic Reports filed with the SEC. Any forward-looking statements speak only as of the date of this press release and are based on information available to Sensei as of the date of this release, and Sensei assumes no obligation to, and does not intend to, update any forward-looking statements, whether as a result of new information, future events or otherwise. Investor Contact: Michael Biega Senior Director, Investor Relations Sensei Biotherapeutics mbiega@senseibio.com Media Contact: Joyce Allaire LifeSci Advisors Jallaire@lifesciadvisors.com