Jasper Therapeutics (JSPR) Jefferies Global Healthcare Conference 2025 summary

Program overview and scientific rationale

• Lead asset briquilimab targets mast cell-driven diseases by blocking the KIT receptor, inducing mast cell apoptosis and offering a favorable safety profile.

• Three ongoing clinical trials focus on chronic spontaneous urticaria, chronic inducible urticaria, and asthma, leveraging optimal biologic dosing to maximize efficacy and minimize adverse events.

• Mast cell depletion, rather than inhibition, is achieved at higher doses, with sustained tryptase reduction indicating effective mast cell targeting.

• The approach allows for drug-free intervals, potentially reducing off-target effects on other KIT-expressing cells.

Clinical trial results and efficacy

• BEACON phase 1/2 study in chronic spontaneous urticaria shows rapid and durable clinical responses, with significant UAS7 score reductions within the first week at 120 mg and 240 mg doses.

• Efficacy at 240 mg dose is durable through eight weeks, with some patients maintaining well-controlled disease up to 12 weeks.

• Comparative data suggest briquilimab efficacy is competitive with approved and investigational therapies in CSU.

• SPOTLIGHT study in inducible urticaria demonstrates high clinical benefit rates (93% at 120 mg), with durability of response being evaluated at 180 mg.

Safety profile and adverse events

• Most adverse events were transient and self-resolving, including hair color changes and taste disturbances, with median resolution time of 31 days.

• KIT-related adverse events are managed by optimizing dosing intervals, reducing constant inhibition of non-target cells.

• One grade 3 neutropenia occurred in a patient with pre-existing conditions, with no further severe events upon continued dosing.

• Neutrophil counts recover by week four, supporting the differentiated safety profile.