Jasper Therapeutics (JSPR) Jefferies 2024 Global Healthcare Conference summary

Strategic focus and pipeline updates

• Lead asset briquilimab is being developed for mast cell-driven diseases, with current studies in chronic spontaneous urticaria (CSU), chronic inducible urticaria (CIndU), and asthma starting later this year.

• Stem cell transplant conditioning regimens have been deprioritized to focus on mast cell-driven indications.

• Asthma was recently added as a new indication, with a phase 1b/2a challenge study set to begin by year-end.

Mechanism of action and differentiation

• Briquilimab is an aglycosylated monoclonal antibody targeting c-Kit, leading to irreversible mast cell depletion via apoptosis.

• This approach is distinct from most therapies, which inhibit mast cell function rather than deplete the cells.

• Depletion provides a prolonged therapeutic window, as mast cell regeneration in the skin can take 18–24 weeks post-dose.

Clinical development and dosing strategy

• Dose-dependent mast cell depletion was observed in healthy volunteer studies, guiding current dosing in urticaria trials.

• Optimal biologic dosing involves depleting mast cells, allowing a drug-free interval, and redosing upon cell return to minimize side effects.

• Side effects such as graying hair, taste changes, and reversible reductions in sperm count are mild, transient, and manageable.