Jasper Therapeutics (JSPR) Stifel 2024 Healthcare Conference summary

Company overview and lead asset

• Clinical-stage biotech focused on mast cell diseases with lead monoclonal antibody briquilimab targeting c-Kit.

• Clinical trials underway in chronic spontaneous urticaria, inducible urticaria, and asthma; first asthma patient dosing imminent.

Clinical data and efficacy

• Spotlight study in inducible urticaria showed 93% clinical response and 83% complete response at six weeks with briquilimab.

• High complete response rates observed at 120 mg dose, with 50% maintaining complete response at six weeks post-dose.

• Durability of response attributed to mast cell depletion, not just drug presence.

Mechanism of action and biomarker insights

• Briquilimab induces mast cell apoptosis by inhibiting c-Kit, with efficacy linked to Cmax rather than AUC.

• Shorter half-life (9 days) may reduce off-target effects on stem cells, melanocytes, and other c-Kit expressing cells.

• Tryptase correlates with efficacy but is not predictive; current assays do not distinguish between alpha and beta tryptase.