Jasper Therapeutics, Inc. announced that the European Medicines Agency (EMA) Committee for Orphan Medicinal Products (COMP) has granted orphan drug designation to briquilimab (formerly known as JSP191), a monoclonal antibody targeting the CD117 (stem cell factor) receptor, for conditioning treatment prior to HCT. Previously, the U.S. Food and Drug Administration granted orphan drug designation to briquilimab in HCT, as well as rare pediatric disease designation for the treatment of severe combined immunodeficiency (SCID). Jasper is currently conducting clinical studies of briquilimab as a conditioning agent prior to hematopoietic stem cell transplant in patients with SCID, a rare, life-threatening, pediatric disorder affecting an estimated 1/58,000 births in the general population, and separately in patients with acute myeloid leukemia (AML) or myelodysplastic syndromes (MDS).

In these diseases, prognosis is poor for patients and transplant rates are low due to the highly toxic conditioning required. Jasper's ongoing clinical trial in SCID is evaluating briquilimab as a conditioning agent to enable stem cell transplantation in patients who are either transplant-naive or who received a prior stem cell transplant with a poor outcome. Jasper presented data from this study at multiple scientific conferences, which demonstrated that briquilimab has been well tolerated with no treatment-related adverse events across multiple patients ranging from 3 months to 38 years old.

Successful stem cell engraftment and immune reconstitution have also been observed. Jasper has also presented data from a study that has demonstrated a tolerable safety profile and full donor chimerism in 24 of 24 patients with AML or MDS. To date, there have been no reports of briquilimab-related significant adverse events, classical acute grade II-IV graft versus host disease, or transplant related mortality within 100 days.

MDS are a group of disorders in which immature blood-forming cells in the bone marrow become abnormal and do not make new blood cells or make defective blood cells, leading to low numbers of normal blood cells, especially red blood cells. In about one in three patients, MDS can progress to AML, a rapidly progressing cancer of the bone marrow cells. Both are diseases of the elderly with high mortality.