8-K: Jasper Therapeutics Reports Highly Positive Briquilimab Data in Chronic Inducible Urticaria SPOTLIGHT Study

Jasper Therapeutics announced positive top-line data from the 180mg cohort of its SPOTLIGHT Phase 1b/2a study of briquilimab for chronic inducible urticaria, showing high complete response rates and a favorable safety profile.

Summary

• Jasper Therapeutics reported positive data from the 180mg cohort of its SPOTLIGHT Phase 1b/2a study of subcutaneous briquilimab in adult participants with chronic inducible urticaria (CIndU).
• 11 of 12 participants (92%) in the 180mg cohort achieved a complete response (CR) to provocation testing within the 8-week preliminary analysis period.
• All 12 participants (100%) in the 180mg cohort achieved a clinical response (CR or PR).
• Efficacy was rapid, with 8 of 12 participants (66%) achieving clinical response by week 2.
• Durability was observed, with 7 of 12 participants (58%) maintaining clinical response through week 8.
• Significant reductions in serum tryptase were observed, with 10 of 12 participants (83%) in the 180mg cohort showing levels below the lower limit of quantification.
• The study enrolled 27 participants across three dose cohorts: 40mg (n=3), 120mg (n=12), and 180mg (n=12).
• Overall, 22 of 27 participants (81%) across all doses achieved a CR, and 26 of 27 participants (96%) achieved a CR or PR.
• Briquilimab continued to be well tolerated, with no serious adverse events (SAEs) and no grade 3 or higher adverse events (AEs) reported in the 180mg cohort.
• Mild, transient drops in neutrophil counts (Grade 1 or 2) were observed in 6 of 12 participants (50%) in the 180mg cohort, resolving in a median of 16 days, with 5 of 6 cases potentially linked to concurrent viral infections.
• No AEs related to hair or skin color changes were reported.
• 2 of 12 participants (17%) in the 180mg cohort experienced taste change/hypogeusia.

Sentiment

Score: 9

Explanation: The clinical data for briquilimab in CIndU is overwhelmingly positive, demonstrating high complete response rates, rapid onset, and a favorable safety profile in a patient population with limited treatment options. This significantly de-risks the program and supports its potential as a leading therapeutic.

Positives

• High complete response rate: 92% (11 of 12) of participants in the 180mg cohort achieved a complete response.
• 100% clinical response: All 12 participants in the 180mg cohort achieved a clinical response (complete or partial).
• Rapid onset of efficacy: 66% (8 of 12) of participants achieved clinical response by week 2.
• Durable response: 58% (7 of 12) of participants maintained clinical response through week 8.
• Significant mast cell depletion: 83% (10 of 12) of participants in the 180mg cohort had tryptase levels below the lower limit of quantification.
• Favorable safety profile: No serious adverse events (SAEs) or Grade 3 or higher adverse events (AEs) reported in the 180mg cohort.
• No hair or skin color changes reported, which are sometimes associated with KIT blockade.
• Neutrophil count decreases were mild (Grade 1 or 2), transient (median resolution 16 days), and potentially linked to concurrent viral infections.
• Demonstrated dose-dependent reductions in serum tryptase and improved CR rates at higher doses (75% CR at 180mg vs. 50% at 120mg at week 6).

Negatives

• Mild, transient drops in neutrophil counts were observed in 50% (6 of 12) of participants in the 180mg cohort, though these resolved quickly and were often associated with viral infections.
• Taste change/hypogeusia experienced by 17% (2 of 12) of participants in the 180mg cohort.

Risks

• General economic, political, and business conditions.
• Risk that potential product candidates may not progress through clinical development or receive required regulatory approvals within expected timelines or at all.
• Risk that clinical trials may not confirm any safety, potency, or other product characteristics described or assumed.
• Risk that prior test, study, and trial results may not be replicated in continuing or future studies and trials.
• Risk that Jasper will be unable to successfully market or gain market acceptance of its product candidates.
• Risk that Jasper's product candidates may not be beneficial to patients or successfully commercialized.
• Patients' willingness to try new therapies and physicians' willingness to prescribe these therapies.
• Effects of competition on Jasper's business.
• Risk that third parties on which Jasper depends for laboratory, clinical development, manufacturing, and other critical services will fail to perform satisfactorily.
• Risk that Jasper's business, operations, clinical development plans and timelines, and supply chain could be adversely affected by the effects of health epidemics.
• Risk that Jasper will be unable to obtain and maintain sufficient intellectual property protection for its investigational products or will infringe the intellectual property protection of others.

Future Outlook

Jasper Therapeutics anticipates continued evaluation of briquilimab in chronic urticaria and other mast cell diseases like chronic spontaneous urticaria (CSU) and asthma, based on the robust efficacy and safety profile observed. Full SPOTLIGHT study results are expected in the second half of 2025. The company believes briquilimab can support optimal biologic dosing by rapidly delivering robust and durable control of urticaria symptoms with a potentially differentiated safety profile.

Management Comments

• "We are very pleased by the updated results from the SPOTLIGHT study, with briquilimab driving complete responses in over 90% of CIndU participants enrolled in the 180mg cohort." Ronald Martell, President and Chief Executive Officer of Jasper.
• "In addition to the responses observed, we are pleased that briquilimab continued to be well tolerated in the study." Ronald Martell.
• "Taken together with the results observed thus far in the BEACON study in CSU, these data demonstrate the ability of briquilimab to support optimal biologic dosing by rapidly delivering robust and durable control of urticaria symptoms, along with a potentially differentiated safety profile." Ronald Martell.
• "It is exciting to see additional clinical data showing that treatment with briquilimab can lead to deep clinical benefit shortly after administration in a difficult-to-treat antihistamine refractory CIndU patient population." Martin Metz, M.D., Professor of Dermatology and Allergy Charité Universitätsmedizin Berlin.
• "Notably, the safety and tolerability results observed in both the SPOTLIGHT and BEACON studies thus far show that the adverse events possibly caused by briquilimab are mostly low frequency, low grade, and resolve quickly." Martin Metz, M.D.
• "Patients with CIndU currently have very few treatment options, and I look forward to continuing to support the development of novel therapeutics to treat this debilitating disease." Martin Metz, M.D.

Industry Context

Chronic inducible urticaria (CIndU) is described as a severe and debilitating inflammatory condition with limited treatment options for antihistamine-refractory patients. Briquilimab, by targeting the KIT receptor to deplete mast cells, addresses the underlying cause of the disease, potentially offering a novel therapeutic approach in an area of high unmet medical need. The results suggest briquilimab could be a significant advancement compared to existing symptomatic treatments.

Comparison to Industry Standards

• The document highlights that CIndU patients currently have "very few treatment options" and are often "antihistamine refractory," indicating a high unmet medical need.
• Briquilimab's mechanism of action (KIT receptor blockade leading to mast cell apoptosis) is presented as a differentiated approach compared to symptomatic treatments.
• The observed efficacy (92% complete response, 100% clinical response in 180mg cohort) and rapid onset (66% clinical response by week 2) are presented as robust, suggesting a potentially superior profile for this difficult-to-treat patient population.
• The safety profile, with no SAEs or Grade 3+ AEs and transient low-grade neutrophil decreases, is emphasized as "well tolerated" and "potentially differentiated safety profile" compared to other biologics.

Stakeholder Impact

• Shareholders: Positive impact due to strong clinical trial results, potentially increasing company valuation and future revenue prospects.
• Patients: Significant positive impact as briquilimab offers a promising new treatment option for chronic inducible urticaria, a debilitating condition with limited current therapies, potentially improving quality of life.
• Healthcare Providers: Provides a new, effective, and well-tolerated therapeutic tool for managing antihistamine-refractory CIndU patients.
• Employees: Positive impact on morale and job security due to successful clinical development and potential for future commercialization.

Next Steps

• Host a conference call and webinar on June 16, 2025, to present the data.
• Continue evaluation of briquilimab in chronic urticaria.
• Full SPOTLIGHT study results expected at a medical conference in the second half of 2025.
• Ongoing clinical studies of briquilimab as a treatment in patients with CSU, CIndU, or asthma.
• Patients may roll over to an open-label extension study evaluating briquilimab at 180mg Q8W.
• Future events/milestones include initial clinical data for CSU Registrational Phase, CIndU OLE Study, Asthma Phase 1b/2a, and next Mast Cell Indication.

Key Dates

Recommendation

Keywords

Briquilimab, SPOTLIGHT study, chronic inducible urticaria, CIndU, mast cell diseases, KIT inhibitor, CD117, clinical trial, Phase 1b/2a, biotechnology, dermatology, allergy, antihistamine refractory, complete response, clinical response, serum tryptase, safety profile, JSPR, Jasper Therapeutics