Jasper Therapeutics (JSPR) Corporate presentation summary

Briquilimab clinical profile and efficacy

• Demonstrates rapid, deep, and durable clinical responses in chronic spontaneous urticaria (CSU), chronic inducible urticaria (CIndU), and asthma, with >25 point UAS7 reductions and complete responses as early as week 2 across multiple cohorts.

• In BEACON and SPOTLIGHT studies, over 50% of CSU patients at 180mg or higher achieved complete response at 4 weeks, and 92% of CIndU patients at 180mg achieved complete response by week 2.

• ETESIAN study in asthma showed improvements in FEV₁ and substantial reductions in eosinophils, supporting further development.

• Open-label extension studies confirm sustained efficacy, with 62% CSU complete response at week 20 and 65% CIndU clinical response at week 16.

• Data support advancing to Phase 2b in CSU (2H 2026) and Phase 3 in CIndU (early 2028).

Safety and tolerability

• Safety profile is favorable, with most adverse events mild, transient, and related to KIT blockade; no dose delays or discontinuations due to adverse events.

• Most common adverse events include nasopharyngitis, taste disorder, neutrophil count decrease, and fatigue, with low rates of serious adverse events.

• In OLE studies, 61.9% reported any adverse event, but only 1.6% discontinued due to adverse events; no treatment-related deaths.

• SPOTLIGHT and ETESIAN studies confirm low-grade, reversible adverse events, with no serious treatment-related events.

Mechanism of action and differentiation

• Briquilimab is a potent, high-affinity KIT inhibitor that directly blocks the SCF binding site, leading to rapid mast cell depletion and apoptosis.

• Drug properties allow for rapid Tmax, high Cmax, and clearance near the end of the 8-week dosing cycle, minimizing KIT-related adverse events.

• Differentiated from other therapies by targeting mast cell survival rather than inhibition or silencing, potentially leading to deeper and more durable efficacy.