FDA Grants Orphan Drug Designation to Cellenkos' CK0804 Treg Therapy for Treatment of Myelofibrosis
-- CK0804 is a first in class, CXCR4hi Treg therapeutic designed to preferentially traffic towards its ligand CXCL12 over expressed in the bone marrow and spleen in myelofibrosis.
-- CK0804 engages with antigen presenting cells within target tissues and undergoes in vivo proliferation to secrete suppressor cytokine, IL-10.
-- CK0804 Tregs mediate resolution of local and systemic inflammation through a non-MHC restricted mechanism.
HOUSTON, Jan. 6, 2026 /PRNewswire/ -- Cellenkos® Inc., a clinical-stage biotechnology company developing allogeneic, off-the-shelf, regulatory T cell (Treg) therapies for autoimmune and inflammatory diseases, announced that the U.S. Food and Drug Administration (FDA) has granted Orphan Drug Designation to its investigational product, CK0804, for treatment of myelofibrosis, a rare blood cancer with an annual incidence of 1-3 new cases per 100,000 people per year and an estimated U.S. prevalence of approximately of 25,000 patients.
CK0804 is composed of CXCR4hi Tregs that preferentially home to its ligand CXCL12, which is overexpressed in the bone marrow and at the sites of extramedullary hematopoiesis including spleen, in myelofibrosis. Upon arrival in the target tissue, CK0804 Tregs engage with antigen presenting cells (APCs), undergo in vivo proliferation, secrete the suppressor cytokine, IL-10 and resolve inflammation in a non-MHC dependent manner, while regulating PDGF-driven pathways involved disease remodeling.
"Receiving Orphan Drug Designation is an important milestone in the clinical development of CK0804 for myelofibrosis and underscores our commitment to advance CK0804 into phase 2 trials to address the unmet need for patients who have not responded to currently available therapies", said Dr. Simrit Parmar, MD, Founder of Cellenkos. "The observed increase in IL-10 and decreases in TGFβ levels in CK0804 responders, together with reductions in pathogenic monocytes in plasma and bone marrow, support the disease modifying potential of CK0804 Tregs as a distinct and differentiated therapeutic class in myelofibrosis."
In a 13‑patient clinical study in myelofibrosis (median age 68 years; range 55–84 years) in which patients had failed a median of two prior therapies (range 1–6), results presented at the 67th Annual Meeting of the American Society of Hematology in December 2025 showed: spleen volume reduction greater than 10% in 45% of 11 evaluable patients; symptom burden reduction greater than 50% in 78% of 9 evaluable patients; and improvement in transfusion burden in all 3 of 3 evaluable patients. At a median follow‑up of 195 days (range 41–809), 10 patients were alive; 3 proceeded to stem cell transplant, 2 switched to a different class of therapy, and the remaining patients continued their initial treatment with ruxolitinib. CK0804 responders demonstrated decreased circulating levels of TGFβ1, TGFβ2, FGF, PDGF, and sCD40L, reduced plasma and bone marrow monocytes, and normalization of the bone marrow myeloid‑to‑erythroid ratio.
About CK0804
CK0804 is an investigational, allogeneic, off‑the‑shelf Treg cell therapy designed to exploit the CXCR4/CXCL12 axis to engage with the antigen presenting cell, undergo in-vivo proliferation to secrete and deliver tissue targeted, payload of suppressor cytokine IL-10, to resolve inflammation in a non-MHC dependent manner. Specifically in myelofibrosis, CK0804 show disease modifying effect as seen by a decrease in pathogenic monocytes in plasma and bone marrow, normalization of myeloid: erythroid ratio of bone marrow, increase in absolute lymphocyte count and decrease in inflammatory cytokines implicated in the pathogenesis of myelofibrosis including TGFβ1, TGFβ2, FGF, PDGF, sCD40L. Derived from clinical‑grade umbilical cord blood and manufactured using Cellenkos' proprietary CRANE® process, CK0804, i) does not require HLA matching with the recipients, ii) escape innate immune surveillance, iii) can be cryopreserved and stored with a shelf life of more than two years where it retains its viability and suppressor function, iv) can be thawed and infused on‑demand, v) intravenously through a peripheral line in an outpatient setting.
About Myelofibrosis
Myelofibrosis (MF) is a rare blood cancer that affects approximately 25,000 patients in the United States. The disease is characterized by scarring (fibrosis) in the bone marrow, spleen enlargement, progressive anemia, fatigue, and early satiety resulting in poor quality of life. The most widely used treatment for MF patients includes type I JAK2 inhibitors, which can improve symptoms and decrease spleen size but have little effect on the underlying cause of disease. Over time, most MF patients stop type I JAK2 inhibitor therapy due to loss of response. The only cure remains allogeneic stem cell transplant however, less than 30% are eligible for this modality due to high risk of treatment related mortality and lack of donors.
About Cellenkos, Inc.
Cellenkos, Inc. is a clinical‑stage biotechnology company developing allogeneic, off‑the‑shelf, T regulatory (Treg) cell therapies for autoimmune and inflammatory diseases. Tregs are key immune cells that resolve pathologic inflammation and maintain immune homeostasis; seminal work on Tregs was recognized with the 2025 Nobel Prize. Cellenkos' proprietary CRANE® platform isolates highly suppressive, stable Tregs from allogeneic umbilical cord blood, providing several advantages:
- No plasticity: Cord blood–derived Tregs remain stable suppressor cells without converting to pro‑inflammatory phenotypes, even in hostile inflammatory environments
- Tissue targeting: Expression of chemokine receptors such as CXCR3, CXCR4, CXCR7, and LFA‑1 allows precise homing to inflamed tissues
- Off‑the‑shelf availability: No HLA matching or donor conditioning is required; cryopreserved products are ready‑to‑use for outpatient administration
- Scalable manufacturing: A single cord blood unit can yield multiple therapeutic doses
Cellenkos operates an in‑house cGMP manufacturing facility in Houston, Texas, overseeing the full value chain from process development through clinical supply.
For more information about Cellenkos, please visit www.cellenkosinc.com
Contact: bd@cellenkosinc.com
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