TScan Therapeutics Secures FDA Agreement for TSC-101 Pivotal Trial, Implements Strategic Restructuring
Key Insights
TScan Therapeutics reached alignment with the FDA on a pivotal study design for TSC-101 to treat acute myeloid leukemia (search) and myelodysplastic syndromes (search), with the trial expected to begin in Q2 2026.
The company implemented a 30% workforce reduction affecting 66 employees to focus resources on hematologic malignancies while pausing solid tumor enrollment.
TScan developed an improved commercial-ready manufacturing process that reduces production time from 17 to 12 days and extends cash runway into H2 2027.
TScan Therapeutics has secured FDA agreement on the pivotal trial design for its lead TCR-T (search) therapy candidate TSC-101, marking a significant regulatory milestone for the clinical-stage biotechnology company. Following a productive End-of-Phase 1 meeting in October 2025, the FDA aligned on the registrational path forward for TSC-101 as a treatment for acute myeloid leukemia (search) (AML (search)) and myelodysplastic syndromes (search) (MDS (search)).
The pivotal study will mirror TScan's ongoing Phase 1 ALLOHA trial, utilizing a biologically assigned internal control arm to support relapse-free survival as the primary endpoint. In this design, patients who are HLA-A02:01-positive with an HLA-A02-negative donor will be assigned to the investigational arm, while patients who are HLA-A*02-01-negative or those for whom an HLA-mismatched donor cannot be found will serve as controls.
Manufacturing Process Improvements
TScan has implemented a commercial-ready manufacturing process that shortens production time by five days, from 17 to 12 days. According to CEO Gavin MacBeath, this improvement "results in substantially lower cost of goods and reduces the need for high levels of ex vivo T cell expansion that we believe may be associated with decreased T cell activity in patients."
The manufacturing optimization addresses recent observations of relapse or prolonged incomplete chimerism in TSC-101 patients enrolled in the Phase 1 study during 2025. These cases appeared to be associated with products that had higher levels of T cell expansion during manufacturing. An initial technology transfer of the improved process to an external contract development and manufacturing organization has been completed.
Strategic Restructuring and Financial Impact
The company announced a strategic prioritization that includes a 30% workforce reduction, affecting approximately 66 employees. This restructuring is expected to generate annual cost savings of $45.0 million in 2026 and 2027, according to Chief Financial Officer Jason A. Amello. The company expects to record a one-time charge of up to $2.3 million in Q4 2025 for severance-related benefits and other costs.
"By focusing clinical development on heme and rightsizing the organization accordingly across all functions, we expect to realize annual cost savings of approximately $45.0 million in 2026 and 2027," Amello stated. "This achieves our goal of preserving capital while continuing to build shareholder value."
Clinical Program Updates
Hematologic Malignancies Program
TSC-101 is designed to treat residual disease and prevent relapse in patients with AML (search) or MDS (search) undergoing allogeneic hematopoietic cell transplantation with reduced intensity conditioning. The FDA has requested that approximately five more patients be dosed at the fixed dose level to support the upper end of the proposed recommended dose range prior to initiating the pivotal trial, now expected to begin in Q2 2026.
Data from the ALLOHA Phase 1 trial, including two-year relapse data on initial patients treated with TSC-101, will be presented at the 67th American Society of Hematology Annual Meeting on December 6, 2025. The presentation is titled "TSC-101 eliminates recipient hematopoietic cells and demonstrates potential for improved relapse-free survival in patients with AML (search), ALL, or MDS (search) undergoing allogeneic HCT: Updated results from the Phase 1 (ALLOHA) trial."
TScan plans to expand HLA coverage of the heme program with two additional investigational new drug applications scheduled for filing in Q4 2025, with the goal of initiating Phase 1 development in H2 2026 subject to additional funding.
Solid Tumor Program Transition
In October 2025, TScan dosed the first two patients with multiplex TCR-T (search) therapy candidates in the PLEXI-T solid tumor trial. Seven patients have been treated to date with singleplex TCR-T at dose level 3 or higher. However, the company is pausing further enrollment to focus resources on the hematologic malignancies program.
TScan expects to share initial safety and efficacy data from the PLEXI-T trial in Q1 2026. The company is shifting to preclinical development of in vivo engineering for solid tumors, having recently partnered with a third party specializing in lentiviral-based platforms for in vivo T cell engineering.
"We have a unique opportunity to develop and potentially commercialize a compelling program for patients with heme malignancies and are well positioned to develop the first in vivo-engineered TCR-T (search) program for patients with solid tumors," MacBeath explained.
Extended Cash Runway
The strategic prioritization extends TScan's cash runway into the second half of 2027, providing financial stability to advance the TSC-101 program through its pivotal development phase. The company's focus on hematologic malignancies represents a strategic decision to concentrate resources on the program with the most advanced regulatory pathway and manufacturing readiness.