Cellenkos Announces FDA Clearance of Investigational New Drug (IND) Application for Phase 1b/ 2a Trial of CK0802 in Steroid-Refractory Graft-versus-Host Disease (GVHD)

Multicenter, open-label study will evaluate the safety and preliminary efficacy of CK0802, a first-in-class, off-the-shelf Treg therapy, in patients with steroid-refractory GVHD

HOUSTON, May 4, 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 cleared 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. While allogeneic stem cell transplants are curative for many blood cancers, the procedure carries the risk of GVHD—a condition where donor cytotoxic T cells "misfire," recognizing the patient's healthy organs as foreign and launching a systemic attack. This typically manifests as severe skin rashes, debilitating diarrhea, and liver failure.

Current first-line treatment relies on high-dose intravenous steroids. However, steroids act as a "blunt instrument," suppressing the aggressive T cells while simultaneously depleting the healthy immune system, leaving patients vulnerable to life-threatening infections. In nearly 50% of cases, steroids fail to calm the immune attack. Currently available second-line therapies often struggle to provide lasting results, frequently hampered by severe immunosuppression and hematologic toxicities. Due to these limitations, patients face a poor prognosis, with two-year survival rates currently stagnating at approximately 30%. Novel therapies are urgently needed.

"FDA clearance to advance CK0802 into a Phase 1b/ 2a trial marks a hopeful step forward for patients facing the dire prognosis of steroid-refractory GVHD," said Simrit Parmar, MD, MSCI, Founder of Cellenkos, and Faculty, 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 de-escalating donor 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 failed to respond adequately to systemic corticosteroid therapy following allogeneic stem cell transplantation.
• Primary endpoint: Safety and early efficacy of CK0802 as assessed by overall response rate (ORR) at Day 29.

The trial is scheduled to commence in the second half of 2026, with a clinical readout anticipated in early 2027.

How can CK0802 treat Steroid Refractory GVHD?
In cases of steroid-refractory GVHD, patients face a life-threatening "vicious loop" of injury and inflammation. This condition is driven by aggressive donor T cells that relentlessly attack the recipient's organs, triggering the release of inflammatory cytokines that further fuel the disease's progression. CK0802 Tregs are designed to break this cycle. Hardwired to remain resilient even under intense inflammatory conditions, CK0802 delivers a concentrated dose of "young," highly functional regulatory T cells (Tregs). These cells employ a multi-faceted biological approach to suppress runaway inflammation at the source, actively promoting long-term immune stability.

• Direct Suppression: By releasing suppressor cytokine, IL-10, CK0802 Tregs apply "molecular brakes" to the immune system, inhibiting pro-inflammatory mediators (TNF-α, IL-6, IL-12, and IL-17), preventing further tissue injury.
  
  
• Indirect Starvation: CK0802 Tregs act as "cytokine sinks," utilizing high-affinity surface receptors to rapidly consume, IL-2, a 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 take aim and neutralize Antigen-Presenting Cells (APCs), which are the primary drivers of GVHD. By silencing these "masterminds", CK0802 extinguish the "cytokine storm" and resolve the inflammatory chaos, to establish durable immune homeostasis.
  
  
• Infectious Tolerance Induction: Beyond immediate action, CK0802 retrain the patient's endogenous regulatory T cells, recruiting the host's immune system to sustain long-term healing and maintain equilibrium.

"Clearance 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, further validating our CRANE^® manufacturing platform," said Tara Sadeghi, Chief Operating Officer of Cellenkos. "This trial will provide critical data to guide the design of future, pivotal studies. We believe that CK0802 will be a transformational therapy for steroid refractory GVHD patients who tragically have limited options today."

Acting as an immunological "crusader," CK0802 is specifically trained to thrive within intense inflammatory environments and home directly towards injured tissues to suppress donor-driven immune attacks, effectively re-establishing immune homeostasis.

CK0802 Phase 1 Trial Outcomes
Results from a randomized, placebo-controlled trial demonstrate that CK0802 Tregs are a safe and highly effective treatment for critically ill COVID-19 ARDS patients, requiring mechanical ventilation and vasopressor support, thought to be driven by severe "cytokine storm" inflammation, like that seen in GVHD. All patients had failed traditional steroid therapy. Bayesian regression analysis revealed a probability of beneficial effect (PBE) of 89.7% for being alive and extubated at day+28 in recipients of multiple infusions of CK0802 at a fixed dose of 100 million Tregs compared to placebo. Long-term data showed a 98.6% PBE for overall survival at the one-year mark, alongside significant improvements in cognitive function and general quality of life six months after hospital discharge in favor of CK0802 at the same dose. These findings suggest that CK0802 could fundamentally shift the prognosis for patients facing the most life-threatening respiratory complications of the virus.

About CK0802
Derived from qualified U.S. public cord blood units in compliance with 21 CFR Part 1271, CK0802 is a pioneering, "off-the-shelf" 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 "ready-to-use" capability is critical for steroid-refractory GVHD patients, where rapid intervention is essential for survival and every hour counts.

At the core of the CK0802 are "supercharged," intelligent regulatory T cells (Tregs) that preserve their cellular naivety. This unique state facilitates rapid in vivo proliferation, enabling the cells to expand aggressively once inside the patient to mount a powerful suppression of the rogue elements. Furthermore, these cells possess a specialized "target readiness" that drives a gain of function; allowing for the swift resolution of dysregulated inflammation—the primary biological driver of GVHD—restoring balance to the immune system when it is needed most.

About Graft-versus-Host Disease
Graft-versus-host disease (GVHD) remains one of the most significant and life-threatening complications following allogeneic hematopoietic stem cell transplantation. Approximately 11,000 allogeneic stem cell transplants are performed annually in the United States, and 80,000 worldwide. Despite modern prophylactic measures, acute GVHD occurs in approximately 50% of transplant recipients, and chronic GVHD impacts between 30% and 70% of patients, severely affecting long-term quality of life and non-relapse mortality. Current standard-of-care treatments rely heavily on high-dose corticosteroids, yet these interventions are only effective in roughly 50% of cases. For those with steroid-refractory disease, the prognosis is often dismal, with 2-year survival rates historically recorded near 30%, highlighting a critical unmet medical need for novel, 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 disorders. Cellenkos was granted US patent (US12472182B2) on November 18, 2025, for their technology covering "Compositions comprising regulatory T cells and methods of producing and using them". Leveraging its proprietary CRANE^® technology, Cellenkos develops off-the-shelf Treg product candidates designed to suppress inflammation and support 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.

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