FDA Grants Fast Track Designation to CK0803 for Amyotrophic Lateral Sclerosis

The FDA has granted Fast Track designation to CK0803, an investigational allogeneic cord blood–derived regulatory T-cell (Treg) therapy, for the treatment of amyotrophic lateral sclerosis (ALS), according to Cellenkos. The designation makes CK0803 the first Treg product to receive Fast Track status for ALS.¹

The FDA’s Fast Track status is intended to facilitate development and expedite review of therapies for serious conditions that have the potential to address an unmet medical need.^1,2

CK0803 Targets Neuroinflammation in ALS

ALS is a progressive neurodegenerative disease characterized by the loss of motor neurons in the brain and spinal cord. Although its pathogenesis is complex, increasing evidence implicates neuroinflammation and dysregulation of the immune system in disease progression. Regulatory T cells can suppress inflammatory immune responses, but both their number and suppressive function can decline as ALS progresses.³

CK0803 is designed to address this immune imbalance. The therapy consists of healthy donor–derived Tregs collected from umbilical cord blood and engineered to express high levels of the homing molecules CXCR3 and CD11a, also known as lymphocyte function–associated antigen 1. These characteristics are intended to help the cells cross the blood-brain and blood-spinal cord barriers and migrate toward areas of central nervous system inflammation.¹

Rather than targeting a single disease-associated antigen, CK0803 is intended to suppress proinflammatory T-helper 1 and T-helper 17 responses and reduce toxic microglial activation. The cells also secrete IL-10, an anti-inflammatory cytokine involved in immune regulation.^1,3

The product is manufactured using Cellenkos’ proprietary CRANE platform and does not require human leukocyte antigen or ABO matching. It is administered as an outpatient intravenous infusion without conditioning chemotherapy or IL-2 support.¹

Early Trial Findings Support Continued Development

CK0803 is being evaluated in the phase 1/1b CK0803-101-1 study (NCT05695521), which is assessing the safety and preliminary activity of the therapy in patients with ALS. Six evaluable patients—3 with spinal-onset disease and 3 with bulbar-onset disease—received up to 9 infusions of 100 million Treg cells. Treatment consisted of 4 weekly induction infusions followed by 5 monthly consolidation infusions.¹

Early findings from this cohort demonstrated stabilization of decline on the ALS Functional Rating Scale-Revised (ALSFRS-R), an approximately 60% decrease in plasma neurofilament light chain (NfL), and an approximately 200% increase in plasma IL-10.¹

These results remain preliminary because of the small number of patients and the early-phase design of the study. NfL is an increasingly studied biomarker of neuronal injury in ALS, while IL-10 is associated with anti-inflammatory immune activity. The findings therefore provide biologic support for the proposed mechanism of CK0803 but do not yet establish clinical efficacy.^1,4

A 2025 study published in NEJM Evidence also evaluated allogeneic umbilical cord blood–derived Tregs in patients with ALS. Participants received 100 million cells through weekly induction followed by monthly infusions. Investigators reported an acceptable preliminary safety profile and signals suggesting that Treg-based treatment warranted further clinical investigation.⁴

Fast Track Status Could Accelerate Development

Fast Track designation gives sponsors opportunities for more frequent communication with the FDA during development and allows eligibility for rolling review, if applicable. Therapies with Fast Track designation can also qualify for other expedited regulatory pathways if separate criteria are met.²

The designation does not indicate that CK0803 has been shown to be safe or effective. FDA guidance emphasizes that Fast Track products must still meet the same statutory standards for approval as other drugs and biologics.²

For CK0803, the designation adds regulatory momentum to an emerging treatment strategy focused on immune dysregulation rather than directly targeting motor neurons. Further clinical investigation will be needed to determine whether the biomarker changes and functional signals observed in the initial cohort translate into durable clinical benefit for patients with ALS.

REFERENCES

1. Cellenkos receives FDA Fast Track designation for CK0803 in amyotrophic lateral sclerosis (ALS). News release. Cellenkos Inc. Published August 25, 2026. Accessed August 26, 2026. https://www.prnewswire.com/news-releases/cellenkos-receives-fda-fast-track-designation-for-ck0803-in-amyotrophic-lateral-sclerosis-als-302859365.html

2. Expedited programs for serious conditions—drugs and biologics. Guidance for industry. FDA. Updated November 28, 2023. Accessed August 26, 2026. https://www.fda.gov/regulatory-information/search-fda-guidance-documents/expedited-programs-serious-conditions-drugs-and-biologics

3. Zhang N, Su WM, Chen T, et al. From pathogenesis to therapy: the emerging role of regulatory T cells in amyotrophic lateral sclerosis. J Neuroinflammation. 2026;23(1):50. doi:10.1186/s12974-025-03677-z

4. Shneider NA, Nesta AV, Rifai OM, et al. Clinical safety and preliminary efficacy of regulatory T cells for ALS. NEJM Evid. 2025;4(5):EVIDoa2400249. doi:10.1056/EVIDoa2400249