Sensei Biotherapeutics, Inc.

Sensei Biotherapeutics, Inc. is a clinical-stage biotechnology company focused on improving outcomes for cancer patients through multi-node inhibition of critical oncogenic pathways. On February 17, 2026, the company completed the acquisition of Faeth Therapeutics, a clinical-stage biotechnology company developing multi-node therapies that target tumor metabolism and signaling. In connection with the Acquisition, the company received $200 million in gross proceeds from a private placement financing from a broad syndicate of investors, including several leading life sciences funds, to advance PIKTOR through key clinical milestones. Following the Acquisition, the company's lead program is PIKTOR, an investigational multi-node inhibitor of the PI3K/AKT/mTOR pathway in development for endometrial and breast cancer.

The company's core scientific thesis is that simultaneously suppressing multiple nodes of a pathway produces deeper, more durable tumor suppression than targeting any single node alone, which may also enable lower drug dosing, potentially contributing to an improved tolerability profile. PIKTOR is comprised of two independently dosed inhibitors of discrete pathway nodes: serabelisib, a selective phosphoinositide 3-kinase alpha inhibitor, and sapanisertib, a mammalian target of rapamycin complexes 1 and 2 inhibitor. The PI3K/AKT/mTOR pathway is dysregulated in up to 50% of all solid tumors, making it one of the most prevalent therapeutic targets in oncology. The company believes PIKTOR may have a substantially differentiated clinical profile versus both currently available and developmental treatments for multiple solid tumors.

PIKTOR is currently being evaluated in an ongoing Phase 2 trial in second-line advanced endometrial cancer (Study FTH-PIK-201), with topline data anticipated by year-end 2026. The primary endpoint for this Phase 2 trial is objective response rate, and the secondary endpoints are progression free survival, PFS at six months, overall survival, clinical benefit rate, duration of response and safety and tolerability by assessment of adverse events and serious adverse events. In May 2026, the company announced that it had dosed the first patient in its Phase 1b trial in HR+/HER2- advanced breast cancer (Study FTH-PIK-101). The primary endpoint for this Phase 1b trial is safety and tolerability by assessment of AEs and SAEs, and the secondary endpoints are ORR, PFS, PFS at six months, overall survival, CBR and DOR.

The company's strategy centers on establishing PIKTOR's initial therapeutic proof of concept in endometrial cancer through the ongoing Phase 2 trial, with topline data anticipated by year-end 2026 and longer-term follow-up data in 2027. Concurrently, the company plans to broaden PIKTOR's development into advanced HR+/HER2- breast cancer through Study FTH-PIK-101, for which the first patient was dosed in May 2026, and expects interim dose escalation data and expansion cohort initiation in 2027, and expansion cohort data in 2028. Beyond these near-term priorities, the company intends to explore PIKTOR's potential as a first-line treatment across targeted indications and may pursue development in additional indications, including ovarian cancer and genetically defined subtypes of lung cancer.

The company also has other pipeline programs, including NEAAR, a regimen that restricts patient intake of specific non-essential amino acids, and IEM, which may improve treatment options for Type I Tyrosinemia. Additionally, the company is completing a Phase 1/2 trial of solnerstotug, its conditionally active monoclonal antibody targeting the immune checkpoint VISTA, and has three preclinical-stage conditionally active antibody programs: SNS-102, SNS-103, and SNS-201. In November 2025, as part of cash preservation measures associated with a previously announced strategic review process, the company's Board of Directors approved a reduction in force of approximately 65% of its workforce, incurring total charges of approximately $1.7 million in connection with the restructuring.

Management anticipates topline data from the ongoing Phase 2 trial in second-line advanced endometrial cancer (Study FTH-PIK-201) by year-end 2026, with longer-term follow-up data in 2027. For the Phase 1b trial in advanced HR+/HER2- breast cancer (Study FTH-PIK-101), the company expects interim dose escalation data and expansion cohort initiation in 2027, and expansion cohort data in 2028. The Phase 1b component of the breast cancer study is anticipated to enroll up to six adult participants per dose level in each cohort, up to a total of 36 patients, with plans to subsequently enroll at least two expansion cohorts of approximately 30 patients each under a future amendment in Phase 2.

The company believes the commercial potential for PIKTOR, if approved, in advanced HR+/HER2- breast cancer and endometrial cancer is substantial, estimating the total addressable market in the United States alone for its currently targeted indications at approximately $6 billion, with HR+/HER2- breast cancer accounting for approximately $5 billion and advanced endometrial cancer the remaining $1 billion. The company intends to utilize its expertise in cancer and metabolic disease to identify additional compelling development opportunities and may advance additional pipeline candidates beyond PIKTOR, including its NEAAR and IEM programs.

The company received $200 million in gross proceeds from a private placement financing in connection with the Acquisition to advance PIKTOR through key clinical milestones. The company is obligated to pay Takeda and Millennium Takeda up to an aggregate of $119.0 million in development, regulatory, and commercial launch milestone payments and up to an aggregate of $250.0 million in sales milestone payments for PIKTOR and any other products that contain both a Serabelisib Compound and a Sapanisertib Program Molecule. The company is also obligated to pay Takeda tiered single-digit royalties on annual net sales of PIKTOR Products and tiered single-digit royalties on annual net sales of Serabelisib Products, as well as tiered high single-digit to low double-digit royalties on annual net sales of all Sapanisertib Products.

The company expects that the Phase 1b breast cancer study will evaluate escalating doses of PIKTOR between 2mg and 4mg of sapanisertib and between 200mg and 300mg of serabelisib administered three days per week over 28-day cycles. The company anticipates selectively expanding its workforce as its clinical and operational needs evolve. The company intends to evaluate the results of the Phase 1/2 trial of solnerstotug in 2026 to determine next steps.

The company faces intense competition from pharmaceutical and biotechnology companies, academic institutions, and research entities, many of which have significantly greater financial resources, established market presence, and expertise in research and development, manufacturing, preclinical and clinical testing, obtaining regulatory approvals, and marketing approved products. The company's commercial opportunity could be reduced or eliminated if competitors develop and commercialize products that are safer, more effective, have fewer or less severe side effects, are more convenient, or are less expensive. Competitors may obtain FDA or other regulatory approval for their products more rapidly, which could result in competitors establishing a strong market position before the company is able to enter the market. The company's intellectual property is subject to risks including that patents may not be granted with respect to pending applications, issued patents may not provide meaningful protection, and trade secrets are difficult to protect. The company is subject to extensive government regulation in the United States and other countries, including requirements for FDA approval through the NDA process, which requires the expenditure of substantial time and financial resources. The company faces risks related to healthcare reform initiatives, including the One Big Beautiful Bill Act signed into law on July 4, 2025, which narrowed access to ACA marketplace exchange enrollment and is expected to reduce Medicaid spending and enrollment. The company is also subject to rapidly changing and increasingly stringent U.S. and foreign laws relating to privacy, data protection, and information security, with potential fines under the GDPR of up to 20 million Euros or 4% of annual global revenue.

Management's message emphasizes the company's transformation following the acquisition of Faeth Therapeutics and the $200 million private placement financing, positioning PIKTOR as the lead program with a differentiated multi-node inhibition approach targeting the PI3K/AKT/mTOR pathway. The key strategic priorities emphasized are establishing PIKTOR's initial therapeutic proof of concept in endometrial cancer through the ongoing Phase 2 trial with topline data anticipated by year-end 2026, broadening PIKTOR's development into advanced HR+/HER2- breast cancer with the first patient dosed in May 2026, and exploring PIKTOR's potential as a first-line treatment across targeted indications. Management also highlights the company's intention to utilize its deep expertise in cancer and metabolic disease to identify additional compelling development opportunities.