8-K: Jasper posts strong CSU data, eyes Phase 2b H2’26

Jasper Therapeutics reported rapid, durable responses and favorable safety for briquilimab in chronic urticaria, enabling dose selection and a planned Phase 2b CSU study in the second half of 2026.

Summary

• Reported positive updated clinical results for briquilimab in CSU (BEACON Phase 1b/2a) and in an open-label extension (OLE) across CSU and CIndU.
• In BEACON Cohort 9.1 (240mg loading then 180mg Q8W; n=6), 83% achieved complete response (CR) by week 3 and 67% achieved CR at week 12, with a 31-point mean UAS7 reduction at week 12.
• In the OLE CSU cohort (180mg Q8W; n=36), 58% achieved CR at week 12 and 75% achieved CR or well-controlled disease (UAS7 ≤ 6) at week 12.
• In the OLE CIndU cohort (n=17), 65% achieved CR or PR at week 16 (8 weeks after second dose).
• Safety across BEACON and OLE remained favorable: no dose-limiting toxicities, KIT-related AEs were infrequent and predominantly low-grade, and most resolved during continued dosing.
• Median duration of follow-up in OLE was 205 days across 63 participants (46 CSU; 17 CIndU).
• Data are sufficient to select doses for a Phase 2b CSU study planned to start in the second half of 2026.
• A conference call and webinar were scheduled for January 8, 2026 at 8:00 a.m. ET to review the data.

Sentiment

Score: 7

Explanation: Clinically meaningful efficacy with rapid onset and a favorable safety profile across BEACON and OLE, enabling Phase 2b planning; tempered by small cohort size in the newest BEACON update, open-label design elements, and customary development and financing risks.

Positives

• Rapid efficacy in BEACON Cohort 9.1 (n=6): 83% CR by week 3 and 67% CR at week 12; mean UAS7 reduction of 31 points at week 12.
• OLE CSU (n=36): 58% CR at week 12 and 75% CR or well-controlled disease (UAS7 ≤ 6) at week 12 on 180mg Q8W.
• OLE CIndU (n=17): 65% CR or PR at week 16 (8 weeks post-second dose), indicating durable responses.
• Favorable safety profile: no dose-limiting toxicities; KIT-related AEs were low frequency, mostly low-grade, and typically resolved on study.
• Extended exposure: median follow-up of 205 days in OLE (n=63), supporting chronic dosing tolerability.
• Clinical dataset deemed sufficient to enable Phase 2b dose selection and advance a CSU registrational program.

Negatives

• Small sample size in the new BEACON Cohort 9.1 efficacy update (n=6 active), limiting statistical precision.
• Open-label extension design (OLE) may introduce bias relative to blinded, controlled trials.
• Treatment-related serious TEAEs occurred in pooled briquilimab BEACON cohorts (2 of 64; 3.1%), and taste disorders/hypogeusia and transient neutrophil count decreases were observed and require monitoring.
• Long-term safety and durability beyond the current median follow-up (~205 days in OLE) remain to be confirmed in larger, controlled studies.

Risks

• Product candidates may not progress through clinical development or receive required regulatory approvals within expected timelines or at all.
• Clinical trials may not confirm safety, potency, or other characteristics observed to date; prior results may not be replicated.
• May be unable to raise capital to continue operations and continue the BEACON study.
• Potential inability to successfully market or gain market acceptance of product candidates if approved; patient and physician adoption uncertainty.
• Competitive pressures could adversely affect the business.
• Reliance on third parties for laboratory, clinical development, manufacturing, and other services presents performance risk.
• Business operations, clinical plans, timelines, and supply chain could be adversely affected by health epidemics.
• Risk of insufficient intellectual property protection or potential infringement of others’ IP.

Future Outlook

Advance briquilimab into a Phase 2b CSU study in the second half of 2026 using two effective dose regimens versus placebo, supported by rapid and durable efficacy and a favorable safety profile observed to date; continue advancing a CSU registrational program and ongoing OLE follow-up.

Management Comments

• Acting CMO Dr. Daniel Adelman highlighted rapid and durable disease control in CSU, strong performance of the 180mg Q8W dose in OLE, and a favorable safety/tolerability profile that supports a differentiated briquilimab profile.
• CEO Jeet Mahal emphasized rapid onset, durable efficacy, and favorable safety with more than six months median follow-up in over 63 patients, stating the data are sufficient for Phase 2b dose selection with a planned start in the second half of 2026.

Industry Context

Anti-KIT mast cell–depleting antibodies are emerging in chronic urticaria; briquilimab’s updated results show rapid UAS7 reductions and high CR/controlled rates consistent with this class. The presentation includes non–head-to-head cross-trial context versus barzolvolimab, reflecting competitive momentum in CSU and CIndU where durable mast-cell targeting could complement or compete with existing biologics.

Comparison to Industry Standards

• At week 12, briquilimab reported CR or well-controlled disease rates of 58% (OLE CSU, n=36) and 67% (BEACON Cohort 9.1, n=6), compared with barzolvolimab Phase 2 CSU topline CR+WC rates of 60% (150mg Q4W, n=52) and 63% (300mg Q8W, n=51) as shown in the company’s slide (not head-to-head).
• Briquilimab demonstrated a 31-point mean UAS7 reduction at week 12 in BEACON Cohort 9.1, with rapid onset (83% CR by week 3), indicating competitive early disease control relative to class benchmarks shown in the slide (not head-to-head).
• Safety profile to date shows no dose-limiting toxicities and predominantly low-grade KIT-related AEs that resolved on study, aligning with expectations for targeted mast-cell depletion therapies.

Stakeholder Impact

• Shareholders: Positive efficacy and safety updates de-risk the program and set a clear path to Phase 2b in H2 2026.
• Patients and caregivers: Potential for rapid symptom control and durable benefit in CSU and CIndU with manageable safety profile.
• Investigators and sites: Advancement toward Phase 2b may increase trial activity and enrollment opportunities.
• Competitors: Comparative context in the presentation underscores active competition in anti-KIT mast cell–depleting therapies.

Next Steps

• Host conference call and webinar on January 8, 2026 at 8:00 a.m. ET to discuss the data.
• Finalize dose selection for briquilimab in CSU based on BEACON and OLE data.
• Commence Phase 2b CSU study in the second half of 2026, expected to enroll approximately 75–100 patients testing two dose regimens versus placebo.
• Continue OLE follow-up to further characterize durability and safety on 180mg Q8W dosing.

Key Dates

Recommendation

The clinical update is encouraging—showing rapid, durable responses and favorable safety that support advancing to Phase 2b in H2 2026. However, the newest BEACON cohort is small (n=6), OLE data are open-label, pivotal timelines remain ahead, and the company flags capital needs as a risk. A hold stance is warranted pending larger, controlled Phase 2b data and greater visibility on financing.

Keywords

briquilimab, chronic spontaneous urticaria, CSU, chronic inducible urticaria, CIndU, KIT, CD117, mast cell depletion, UAS7, BEACON study, open-label extension, Phase 2b, Jasper Therapeutics, allergic asthma, barzolvolimab