Tr1X, a clinical-stage biopharmaceutical company, announced that the U.S. Food and Drug Administration has cleared its Investigational New Drug application for TRX319, an allogeneic CAR-Tr1 Treg cell therapy designed to treat progressive multiple sclerosis. The company simultaneously secured $50 million in venture financing to extend its cash runway into 2027.
Novel CAR-Tr1 Approach for Progressive MS
TRX319 represents a first-in-class allogeneic, off-the-shelf CAR-Tr1 Treg cell therapy engineered to pair targeted B-cell control with active anti-inflammatory signaling and T-cell regulation. The therapy aims to restore immune balance while leveraging scalable, commercially viable manufacturing processes.
"Progressive MS remains a major clinical challenge—patients can accumulate disability outside of relapses, and therapeutic options are limited," said Jennifer Graves, M.D., Ph.D., M.A.S., Vice Chair of Human Research and Division Head of Neuroimmunology at University of California San Diego. "The exploration of new approaches, such as this first-in-human study of an allogeneic CAR-Tr1 Treg cell therapy that carefully evaluates its potential with clear safety and pharmacodynamic objectives is timely and important."
Preclinical Data and Clinical Trial Design
In preclinical studies, TRX319 demonstrated robust central nervous system penetration and CD19-specific cytotoxicity along with IL-10–associated regulatory activity on both self-reactive T cells and activated microglia. The therapy also showed suppression of key pro-inflammatory cytokines—all features consistent with a Tr1 phenotype.
The upcoming multicenter, open-label, dose-escalation Phase 1/2a study will evaluate safety and tolerability as primary objectives, with pharmacodynamic, clinical disability, and biomarker assessments as secondary and exploratory measures. The trial is on track to initiate in early 2026.
"An approach that targets B-cell biology while actively modulating inflammatory signaling within a regulatory cell-therapy framework is a distinct and promising hypothesis in progressive MS," said Bruce Cree, M.D., Ph.D., M.A.S., the George A. Zimmermann Endowed Professor in Multiple Sclerosis in the Department of Neurology at the University of California San Francisco.
Company Progress and Pipeline
David de Vries, co-founder and CEO of Tr1X, expressed satisfaction with the regulatory milestone and the company's broader progress. "We are pleased to receive IND clearance for TRX319 and to advance our second program into the clinic in early 2026," he said. "We are also encouraged by early safety, PK/PD, and clinical signals from our ongoing TRX103 studies in refractory Crohn's disease and mismatched hematopoietic stem cell transplant, and we plan to share initial data from these trials in the coming months."
The $50 million financing will allow Tr1X to advance both the TRX319 Phase 1/2a study and the ongoing TRX103 Phase 1/2a trial for patients with refractory Crohn's disease. TRX103 is an investigational allogeneic off-the-shelf engineered T cell product generated from CD4+ cells sourced from healthy donors, designed to dampen inflammation and help restore immune tolerance.
Technology Platform
Tr1X develops off-the-shelf, allogeneic Tr1 and CAR-Tr1 Treg cell therapies engineered for superior safety, scalability and accessibility. The platform eliminates the need for standard lymphodepletion and enables durable restoration of immune tolerance. The company was founded by leading scientists who discovered Tr1 cells and is supported by top-tier investors including The Column Group, NEVA SGR and Alexandria Venture Investments.
