The US Food and Drug Administration (FDA) has granted fast track designation to Jasper Therapeutics’ antibody, JSP191, for the treatment of severe combined immunodeficiency (SCID) patients who undergo allogeneic hematopoietic stem cell transplant. 

A humanised anti-CD117 monoclonal antibody, JSP191 hinders stem cell factor receptor signalling, resulting in hematopoietic stem and progenitor cell clearance from the bone marrow.

Currently in the clinical stage, the antibody is being developed as a stem cell transplant conditioning agent. It aids in creating a vacant space for the donor or gene-corrected transplanted stem cells to be engrafted. 

In an ongoing multicentre clinical trial, JSP191 has so far been analysed in 14 patients with SCID.

The antibody was also analysed in a total of more than 110 healthy subjects and patients. 

Jasper Therapeutics president and CEO Ronald Martell said: “Patients born with SCID have a severely compromised immune system and need to rely on an allogeneic hematopoietic stem cell transplant to create the immune cells needed to fight infection. 

“Along with the FDA’s previous designations of Orphan and Rare Pediatric Disease for JSP191, this new Fast Track designation recognises the potential role of JSP191 in improving clinical outcomes for these patients and will allow us to more closely work with the FDA in the upcoming months to determine a path toward a Biologics License Application (BLA) submission.”

Apart from SCID, three other trials of JSP191 for myelodysplastic syndromes (MDS)/ acute myeloid leukaemia (AML), Fanconi anaemia (FA) and sickle cell disease undergoing allogeneic transplant are progressing. 

The company plans to advance the antibody to clinics as a second-line therapy in transfusion-dependent, reduced-risk MDS patients later in the year.