Houston-based Cellenkos, Inc. announced receipt of US FDA Fast Track Designation for CK0803, an allogeneic cord blood-derived T-regulatory (Treg) cell therapy, for the treatment of amyotrophic lateral sclerosis (ALS). The designation, communicated by the FDA's Office of Therapeutic Products within the Center for Biologics Evaluation and Research (CBER) in a letter dated August 21, 2026, was granted under Section 506(b) of the Federal Food, Drug, and Cosmetic Act in connection with Investigational New Drug (IND) application IND 28681. Cellenkos says CK0803 is the first Treg cell therapy to receive this designation for ALS.
The clinical signal supporting the designation draws on two sources: six evaluable patients enrolled in the ongoing Phase I/Ib REGALS trial (NCT05695521), and a compassionate-use cohort reported in NEJM Evidence in April 2025. Across both datasets, the company reported an approximately 60% decrease in plasma neurofilament light chain (NfL) — a biomarker of active neuronal injury — and an approximately 200% increase in plasma interleukin-10 (IL-10), consistent with the proposed anti-inflammatory mechanism. Functional data from the published compassionate-use cohort showed the ALSFRS-R rate of decline slowed from −1.66 points per month before treatment to −0.41 points per month on treatment, across six patients with a median follow-up of 18 months. No dose-limiting toxicities have been observed across the Treg platform to date, and all six participants in the published cohort were alive at last follow-up.
CK0803 is engineered to overexpress CXCR3 and CD11a (LFA-1), enabling the cells to cross the blood-brain and blood-spinal cord barriers by migrating along CXCL10 chemokine gradients toward sites of active central nervous system (CNS) inflammation. Rather than targeting a single disease-specific antigen, the therapy is designed to suppress Th1/Th17-driven microglial activation and secrete IL-10 to restore neuroimmune homeostasis. The product requires no HLA or ABO matching and is administered as an outpatient intravenous infusion without conditioning chemotherapy.