Jasper Therapeutics, Inc. announced that new positive data for briquilimab (formerly known as JSP191), will be presented at the 2023 Tandem Meetings: Transplantation & Cellular Therapy Meetings of ASTCT and CIBMTR, taking place on February 15-19, 2023 in Orlando, Florida. Three abstracts, covering data related to the Phase 1 study of briquilimab in combination with fludarabine and low-dose irradiation (Flu/TBI) conditioning in older adults (62 to 79 years) with acute myeloid leukemia (AML) or MDS undergoing allogeneic hematopoietic cell transplant (HCT), will be presented. The studies demonstrate that a regimen of briquilimab plus Flu/TBI leads to successful engraftment of donor blood stem cell without the usual short and long-term toxicities that accompany alternative busulfan-based regimens commonly used in transplant of donor or gene-corrected cells.

Based on its mechanism of action, briquilimab is known to potently synergize with radiation, amplifying its stem cell depleting effects without increasing off-target toxicity. The first abstract demonstrates that briquilimab was safe, well-tolerated, and achieved durable remissions in 8 of 12 of the first treated AML patients. All 8 patients were relapse-free at one-year follow up.

Six of 9 patients who entered transplant with detectable AML, a group known to have a poor prognosis with high relapse rates, showed long-term eradication of the AML clones at one-year. In a companion abstract, the total group of 29 AML and MDS patients treated with briquilimab and Flu/TBI demonstrated lower than expected rates of acute and chronic graft-versus-host disease (GVHD). The third abstract, to be presented in the Best Abstract session, evaluated the costs and healthcare utilization of 12 briquilimab plus Flu/TBI study patients who received outpatient conditioning and donor cell transplant at a single study center.

During the first 100 days post-procedure there were a total of 7 hospitalizations in the 12 patients, with an overall mean stay of 4 days. These results demonstrate the feasibility and potential significant cost savings of outpatient briquilimab plus Flu/TBI conditioning followed by outpatient donor cell transplant in older patients with AML or MDS.