Sensei Biotherapeutics reported second quarter 2025 financial results while providing updates on its lead cancer immunotherapy program targeting the VISTA checkpoint pathway. The clinical-stage biotechnology company announced completion of enrollment in its Phase 1/2 dose expansion cohort and outlined plans for multiple Phase 2 studies across PD-(L)1 resistant tumor types.
Clinical Program Advances
The company's ongoing multi-center Phase 1/2 clinical trial has completed enrollment in the dose expansion cohort with a total of 64 patients. The study includes 10 "cold" microsatellite stable colorectal cancer (MSS CRC) patients receiving solnerstotug monotherapy and 54 patients in the cemiplimab combination arm, consisting of 10 "cold" MSS CRC patients and 44 "hot" tumor patients. Notably, 41 of the 44 patients in the "hot" tumor cohort had received and progressed on a prior PD-(L)1 inhibitor.
"The second quarter was a key inflection point for Sensei, as we now transition from early response-focused readouts to longer-term and commercially relevant efficacy signals with the maturity of the data from our Phase 1/2 study of solnerstotug," said John Celebi, President and CEO of Sensei.
Full dose expansion data, including 6-month progression-free survival (PFS), continues to be expected by year-end 2025. In March 2025, the company announced favorable preliminary clinical data in PD-(L)1 resistant patients from the dose expansion stage, demonstrating favorable activity in patients with PD-(L)1 resistant "hot" tumors.
Safety Profile and Combination Potential
Solnerstotug has demonstrated a favorable safety profile throughout the trial. The therapy continued to be well tolerated, with no dose-limiting toxicities observed and the majority of adverse events being Grade 1 or 2 in severity. Importantly, in combination with cemiplimab, solnerstotug has not demonstrated significant additional toxicity relative to what is typically observed with PD-(L)1 monotherapy.
"Solnerstotug has demonstrated a favorable safety profile and in combination with cemiplimab has not demonstrated significant additional toxicity relative to what is typically observed with PD-(L)1 monotherapy, which we believe could translate into better patient adherence and more meaningful long-term outcomes with continued treatment, as well as physician preference and payor interest," Celebi noted.
VISTA Checkpoint Targeting Mechanism
Solnerstotug (formerly SNS-101) is a conditionally active antibody designed to selectively target the immune checkpoint VISTA (V-domain Ig suppressor of T cell activation) within the tumor microenvironment. VISTA is implicated in numerous cancer indications and its expression correlates with low survival rates. The therapy is designed to block the VISTA checkpoint selectively within the low pH tumor microenvironment, where VISTA acts as a suppressor of T cells by binding the receptor PSGL-1.
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.
Strategic Positioning and Market Opportunity
The company envisions multiple Phase 2 studies across PD-(L)1 resistant tumor types, aligned with unmet need and commercial potential. Celebi emphasized that these differentiated opportunities are viewed as potentially derisking overall, while positioning solnerstotug for multiple indications in high-value immunotherapy segments of the approximately $50 billion PD-(L)1 market.
"We continue to work on finalizing the Phase 2 strategy for solnerstotug, which will be strongly influenced by the full dose expansion dataset we plan to present later this year," added Celebi.
Upcoming Data Presentation
On July 30th, the company announced that clinical data from the dose expansion cohort of the Phase 1/2 trial of solnerstotug alone and in combination with cemiplimab will be presented in a mini oral session at the European Society for Medical Oncology (ESMO) Congress 2025, being held October 17-21, 2025 in Berlin, Germany.
Financial Position
Cash, cash equivalents and marketable securities were $28.6 million as of June 30, 2025, compared to $41.3 million as of December 31, 2024. Sensei expects its current cash balance to fund operations into the second quarter of 2026.
Research and development expenses decreased to $2.5 million for the quarter ended June 30, 2025, compared to $4.6 million for the same period in 2024, primarily due to lower personnel and facilities costs, and reduced manufacturing costs. General and administrative expenses were $2.7 million, down from $3.2 million in the prior year quarter. Net loss was $4.9 million for the quarter, compared to $7.1 million in the second quarter of 2024.
The company regained Nasdaq compliance following a 1-for-20 reverse split of its common stock, which became effective on June 16th, with the subsequent 10-day bid price remaining above $1.
