Briquilimab (Formerly JSP191)

Briquilimab (JSP191) is an unconjugated, aglycosylated, anti-c-Kit antibody that functionally blocks the interaction of the c-Kit receptor from its ligand, stem cell factor (SCF). The interaction of SCF and c-Kit is required for mast cells to survive. By blocking SCF from binding to c-Kit and disrupting the critical survival signal, briquilimab causes mast cells to undergo orderly cell death. For mast cell-driven diseases such as chronic urticaria, this removes the underlying source of the inflammatory response. In low-to-intermediate risk MDS, briquilimab blocks critical cell survival signals, depleting Kit-expressing MDS cells. For stem cell transplant, briquilimab blocks the ability of stem cells to recover from low intensity radiation, thereby opening the specific niches in the bone marrow for donor or gene-corrected hematopoietic stem cells to engraft.

Mechanism Of Action

Clinical Development

To date, briquilimab has been evaluated in more than 145 healthy volunteers and patients. This humanized antibody is being studied in Jasper-sponsored clinical trials in multiple diseases.

  • Chronic Spontaneous Urticaria (ongoing): Phase 1b/2a BEACON study to evaluate briquilimab as a chronic therapeutic for patients with Chronic Spontaneous Urticaria. (NCT06162728)
  • Chronic Inducible Urticaria (upcoming): A clinical study to evaluate briquilimab as a chronic therapeutic for patients with Chronic Inducible Urticaria.
  • Low to Intermediate Risk MDS (ongoing): A clinical study to evaluate briquilimab as a chronic therapeutic for transfusion dependent low to intermediate risk MDS patients. (NCT05903274)
  • SCID Transplant (ongoing): Phase 1/2 dose-escalation and expansion trial is evaluating briquilimab as a sole conditioning agent to achieve donor stem cell engraftment in patients undergoing hematopoietic stem cell transplantation for SCID, which is potentially curable only by this type of treatment. (NCT02963064)

See our expanding pipeline here.

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