Jasper Therapeutics Announces Positive Follow-up Clinical Data from Investigator-Sponsored Study of Briquilimab Conditioning in Sickle Cell Disease Patients

Jasper Therapeutics, a biotechnology company focused on developing novel antibody therapies targeting c-Kit (CD117) to address diseases such as chronic spontaneous urticaria and lower to intermediate-risk myelodysplastic syndromes as well as novel stem cell transplant conditioning regimes, announced that additional follow-up data from Jasper’s investigator-sponsored study of briquilimab (formerly known as JSP191) as a conditioning agent in the treatment of sickle cell disease (SCD) were presented today in a plenary session focused on novel antibody-based conditioning regimens at the 2023 Tandem Meetings: Transplantation & Cellular Therapy Meetings of ASTCT and CIBMTR. Dr. John F. Tisdale, Director of the Cellular and Molecular Therapeutics Laboratory, National Heart, Lung, and Blood Institute, delivered the talk, titled “Improving the Landscape for Curative Therapies in Sickle Cell Disease with Novel Conditioning Methods.”

The study is a Phase 1/2 clinical trial (NCT05357482) evaluating the addition of briquilimab, Jasper’s anti-c-Kit monoclonal antibody, to an existing bone marrow transplantation regimen (NCT00061568) in individuals with SCD and beta thalassemia considered at high risk for complications from or ineligible for standard myeloablative hematopoietic stem cell transplant. The addition of briquilimab is being studied as a potential way to achieve a higher percentage of healthy donor stem cell engraftment (donor chimerism) without increased toxicity.

“We are encouraged by the continued positive data from this important study led by Dr. Tisdale and the National Institutes of Health for a high unmet need population,” said Ronald Martell, President and Chief Executive Officer of Jasper. “There is significant room for improving outcomes for curative therapies in sickle cell disease through targeted antibody-based conditioning for both stem cell transplant as well as gene therapy. These data add to our confidence that directly targeting c-Kit with briquilimab has promise to contribute to that goal and to address a range of rare and chronic diseases driven by stem cells and mast cells.”

For SCD and beta-thalassemia, transplantation of healthy donor stem cells is a multi-step process. After donor cells are collected, a human subject’s existing stem cells must be cleared from the bone marrow to make space for the transplanted cells, which is known as bone marrow conditioning. Next, the newly transplanted cells must survive and replicate within the bone marrow, which is known as bone marrow engraftment. The extent of engraftment is measured by the proportion of the donor cells and the human subject’s own cells, which is known as donor chimerism. As has been shown, improving chimerism is crucial to lead to a sufficient proportion of healthy donor stem cells that produce healthy red blood cells and reverse the sickle phenotype after the stem cell transplant.