Cellenkos, a clinical-stage biotech developing off-the-shelf regulatory T cell (Treg) therapies, announced a major regulatory milestone: the US FDA has granted Orphan Drug Designation to its investigational therapy for the treatment of myelofibrosis, a rare and aggressive blood cancer.

 

CK0804, the therapy, is engineered with CXCR4hi Tregs that home to CXCL12-rich tissues, including the bone marrow and spleen, where myelofibrosis-driven inflammation occurs. Once in the target tissue, CK0804 Tregs interact with antigen-presenting cells, proliferate in vivo, secrete the suppressor cytokine IL-10, and curb inflammation without relying on MHC, while also regulating PDGF-driven disease pathways.

 

"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, Founder of Cellenkos.

 

She added, "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."

 

Early clinical results are encouraging. In a 13-patient study of heavily pretreated individuals (median age 68; range 55–84), the therapy achieved -- spleen volume reduction >10% in 45% of 11 evaluable patients, symptom burden reduction >50% in 78% of 9 evaluable patients, and improved transfusion needs in all 3 of 3 evaluable patients.

 

At a median follow-up of 195 days, 10 patients remained alive; 3 proceeded to stem cell transplants, 2 switched therapies, and the rest continued on ruxolitinib. Responders exhibited 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.