A Multicenter, Open-Label Study Will Evaluate the Safety and Preliminary Efficacy of CK0802, a First-in-Class, Commercially Available Treg Therapy, in Patients With Steroid-Refractory GVHD
HOUSTON, May 5, 2026 /PRNewswire/ — Cellenkos®Inc., a clinical-stage biotechnology company pioneering allogeneic tissue-targeted regulatory T cell (Treg) therapies, today announced that the U.S. Food and Drug Administration (FDA) has authorized its Investigational New Drug Application to initiate a Phase 1b/2a clinical trial of CK0802 for the treatment of patients with steroid-refractory graft-versus-host disease (GVHD).
Steroid-refractory GVHD represents a critical unmet need in post-transplant care. Although allogeneic stem cell transplants are curative for many blood cancers, the procedure carries a risk of GVHD, a condition in which the donor’s cytotoxic T cells “misfire,” recognizing the patient’s healthy organs as foreign and launching a systemic attack. This usually manifests as severe skin rashes, debilitating diarrhea, and liver failure.
Current first-line treatment is high-dose intravenous steroids. However, steroids act as a “blunt instrument,” suppressing aggressive T cells while simultaneously depleting the healthy immune system, leaving patients vulnerable to life-threatening infections. In almost 50% of cases, steroids fail to calm the immune attack. Currently available second-line treatments often struggle to provide durable results, often hampered by severe immunosuppression and hematologic toxicities. As a result of these limitations, patients face a poor prognosis, with two-year survival rates currently stagnant at around 30%. New therapies are urgently needed.
“The FDA’s approval to advance CK0802 into a Phase 1b/2a trial marks a hopeful step forward for patients facing the dismal prognosis of steroid-refractory GVHD,” said Simrit Parmar, MD, MSCICellenkos founder and professor, Texas A&M, School of Engineering and Medicine (EnMed). “CK0802 is uniquely qualified to function under intense inflammatory stress, resetting the patient’s immune system and defusing the donor’s T cell attack without the toxicities typically associated with broad-spectrum immunosuppression. »
About the CK0802 phase 1b/2a study
The multicenter, open-label Phase 1b/2a trial is designed to evaluate the safety, tolerability, and preliminary efficacy of multiple infusions of CK0802.
- Target population: Patients with GVHD who have not responded adequately to systemic corticosteroid therapy after allogeneic stem cell transplantation.
- Main criterion: Safety and early efficacy of CK0802 as assessed by overall response rate (ORR) at day 29.
The trial is expected to begin in the second half of 2026, with clinical readout planned for early 2027.
How can CK0802 treat steroid-refractory GVHD?
In case of steroid refractory GVHDpatients face a “vicious loop” of injury and potentially fatal inflammation. This condition is caused by aggressive T cells from the donor that relentlessly attack the recipient’s organs, triggering the release of inflammatory cytokines that further fuel the progression of the disease. CK0802 Tregs are designed to break this cycle. Designed to remain resilient even under intense inflammatory conditions, CK0802 delivers a concentrated dose of highly functional “young” regulatory T cells (Tregs). These cells employ a multifaceted biological approach to suppress uncontrolled inflammation at the source, thereby promoting long-term immune stability.
- Direct deletion: By releasing a suppressive cytokine, IL-10CK0802 Tregs apply “molecular brakes” to the immune system, inhibiting pro-inflammatory mediators (TNF-α, IL-6, IL-12 and IL-17), thereby preventing further tissue damage.
- Indirect starvation: CK0802 Tregs act as “cytokine sinks,” using high-affinity surface receptors to rapidly consume, IL-2a survival cytokine for aggressive T cells. By draining this lifeline, CK0802 effectively starves and depletes the cytotoxic T cells responsible for attacks on target organs.
- APC neutralization: CK0802 Tregs target and neutralize Antigen-presenting cells (APC)which are the main drivers of GVHD. By silencing these “brains,” CK0802 turns off the “cytokine storm” and resolves inflammatory chaos, to establish lasting immune homeostasis.
- Induction of infectious tolerance: Beyond immediate action, CK0802 retrains the patient Endogenous regulatory T cellsrecruiting the host’s immune system to maintain long-term healing and maintain balance.
“The authorization of our IND application is a major milestone for Cellenkos and confirms that the FDA is satisfied with the clinical, preclinical and manufacturing data submitted in support of CK0802, thereby validating our CRANE.® manufacturing platform,” said Tara SadeghiDeputy Managing Director of Cellenkos. “This trial will provide essential data to guide the design of future pivotal studies. We believe CK0802 will be a transformational therapy for steroid-refractory GVHD patients who unfortunately have limited options today.
Acting like a immunological “crossover” CK0802 is specifically trained to thrive in intense inflammatory environments and travel directly to injured tissues to suppress donor-induced immune attacks, effectively restoring immune homeostasis.
Results from the CK0802 phase 1 trial
Results from a randomized, placebo-controlled trial demonstrate that CK0802 Tregs are a safe and highly effective treatment for critically ill patients with COVID-19 ARDS, requiring mechanical ventilation and vasopressor support, thought to be caused by severe “cytokine storm” inflammation, such as that seen in GVHD. All patients had failed traditional corticosteroid therapy. Bayesian regression analysis revealed a probability of beneficial effect (PBE) of 89.7% for being alive and extubated on day +28 in recipients of multiple infusions of CK0802 at a fixed dose of 100 million Treg compared to placebo. Long-term data showed a PBE of 98.6% for one-year overall survival, as well as significant improvements in cognitive function and general quality of life six months after hospital discharge in favor of CK0802 at the same dose. These results suggest that CK0802 could fundamentally alter the prognosis of patients facing the virus’s most life-threatening respiratory complications.
About CK0802
Derived from US public cord blood units qualified in accordance with 21 CFR Part 1271, CK0802 is a pioneering, “ready-to-use” cryopreserved Treg therapy. Featuring a robust shelf life of nearly three years, this investigational treatment is designed for immediate intravenous administration without the logistical delay of HLA matching. This “out-of-the-box” capability is essential for steroid-refractory GVHD patients, where rapid intervention is critical to survival and every hour counts.
At the heart of CK0802 are “supercharged” intelligent regulatory T cells (Tregs) that preserve their cellular naivety. This unique state facilitates fast alive proliferationallowing cells to grow aggressively once inside the patient to create powerful suppression of unwanted elements. Additionally, these cells have a specialized “target readiness” that results in gain of function; enabling rapid resolution of dysregulated inflammation – the primary biological driver of GVHD – restoring balance to the immune system when needed most.
About graft-versus-host disease
Graft-versus-host disease (GVHD) remains one of the most significant and potentially life-threatening complications after allogeneic hematopoietic stem cell transplantation. Approximately 11,000 allogeneic stem cell transplants are performed each year in the United States and 80,000 worldwide. Despite modern prophylactic measures, acute GVHD occurs in approximately 50% of transplant recipients, and chronic GVHD affects between 30% and 70% of patients, seriously affecting long-term quality of life and non-relapse mortality. Current standard treatments rely largely on high-dose corticosteroids, but these interventions are only effective in about 50% of cases. For those with steroid-refractory disease, the prognosis is often poor, with historically recorded 2-year survival rates approaching 30%, highlighting a critical unmet medical need for new and more effective therapeutic options.
About Cellenkos®Inc.
Cellenkos® is a Houston-based, fully integrated biotechnology company focused on developing transformative Treg therapies for inflammatory diseases and autoimmune diseases. Cellenkos was granted a US patent (US12472182B2) on November 18, 2025 for its technology covering “compositions comprising regulatory T cells and methods of production and use thereof.” Take advantage of your exclusive SKULL® technology, Cellenkos is developing off-the-shelf Treg product candidates designed to suppress inflammation and promote tissue repair. The Company’s pipeline includes candidates for aplastic anemia (CK0801); amyotrophic lateral sclerosis, dementia and psoriasis (CK0803); and myelofibrosis, type 1 diabetes and inflammatory bowel disease (CK0804).
For more information, please visit www.cellenkosinc.com.
Media and investor contact: contact@cellenkosinc.com
Forward-looking statements
This press release contains forward-looking statements regarding the clinical development of CK0802. These statements are subject to risks and uncertainties that could cause actual results to differ materially from those projected.
SOURCE Cellenkos, Inc.
