8-K: Jasper Therapeutics Reports Mixed Briquilimab Trial Results Amidst Drug Product Lot Issue, Halts Asthma and SCID Programs

Jasper Therapeutics announced updated clinical data for its briquilimab therapy in chronic spontaneous urticaria, showing strong efficacy in some cohorts but revealing a confounding drug product lot issue that led to halting its asthma and SCID programs and delaying its Phase 2b CSU study.

Summary

• Jasper Therapeutics reported updated data from its BEACON Phase 1b/2a study of subcutaneous briquilimab in adult participants with chronic spontaneous urticaria (CSU).
• In the 240mg and 360mg single-dose cohorts, 8 of 9 participants (89%) achieved a complete response (UAS7=0), with 7 of 9 (78%) achieving a clinical response by week 2.
• Participants in the open-label extension study dosing at 180mg Q8W demonstrated robust clinical efficacy, with 8 of 11 (73%) achieving a complete response at 12 weeks.
• Results from the 240mg Q8W and the 240mg followed by 180mg Q8W dose cohorts appear to be confounded by an issue with one drug product lot (Lot A34954), affecting 10 of 13 patients.
• Patients dosed with the problematic lot showed lower than expected drops in mean tryptase levels and no discernable impact on UAS7 scores, while 2 patients dosed with a different lot achieved complete responses.
• The Company is investigating the drug product lot issue, with results expected in the coming weeks.
• Due to the drug product lot issue, the ETESIAN trial evaluating briquilimab in asthma has been halted, and development in SCID has also been halted.
• Jasper plans to enroll an additional 10-12 patients across the two impacted multi-dose CSU cohorts to ensure a robust data set for Phase 2b dose selection.
• Data from these additional BEACON patients is expected in Q4 2025, and commencement of the Phase 2b CSU study is now expected in mid-2026.
• The Company is implementing cost-cutting measures, including a potential restructuring, to extend its cash runway and reduce expenses.
• Briquilimab continued to be well tolerated with no grade 3 or higher treatment-related adverse events observed across studies.

Sentiment

Score: 4

Explanation: The sentiment is mixed to negative. While single-dose and open-label extension data for CSU are strong and positive, the significant drug product lot issue impacting multi-dose cohorts, leading to program halts in asthma and SCID, and a delay in the pivotal CSU study, introduces substantial uncertainty and operational challenges. The need for cost-cutting measures further underscores financial pressures.

Positives

• Briquilimab demonstrated deep and rapid disease control in the 240mg and 360mg single-dose cohorts, with 89% of participants achieving a complete response.
• The 180mg Q8W dose in the open-label extension study showed robust clinical efficacy, with 73% of participants achieving a complete response at 12 weeks.
• Substantial reductions in serum tryptase were observed as early as week 1, correlating with clinical responses, and 80% of single-dose participants had tryptase levels below the lower limit of quantification.
• Briquilimab maintained a favorable safety profile across studies, with no dose-limiting toxicities or grade 3 or higher treatment-related adverse events reported.
• Mild and predictable decreases in neutrophil counts were observed but generally resolved, with a median time to resolution of 42 days in single-dose cohorts, and no discontinuations or dose delays due to these reductions.

Negatives

• Results from the 240mg Q8W and 240mg followed by 180mg Q8W dose cohorts were confounded by an issue with one drug product lot (Lot A34954), impacting 10 of 13 patients.
• Patients dosed with the problematic lot showed lower than expected drops in mean tryptase levels and no discernable impact on UAS7 scores.
• The ETESIAN study in asthma has been halted due to the same drug product lot issue.
• Development in SCID has been halted to focus resources on advancing briquilimab in CSU.
• Commencement of the Phase 2b CSU study is now expected in mid-2026, a delay from previous expectations.

Risks

• General economic, political, and business conditions could impact operations.
• Potential product candidates may not progress through clinical development or receive required regulatory approvals within expected timelines or at all.
• Clinical trials may not confirm any safety, potency, or other product characteristics described or assumed.
• Prior test, study, and trial results may not be replicated in continuing or future studies and trials.
• The investigation into the drug product lot issue may be inconclusive or may not lead to the anticipated conclusion.
• Inability to raise capital to continue operations and the BEACON study.
• Inability to successfully market or gain market acceptance of product candidates.
• Patients' willingness to try new therapies and physicians' willingness to prescribe these therapies.
• Effects of competition on the Company's business.
• Third parties on which the Company depends for laboratory, clinical development, manufacturing, and other critical services may fail to perform satisfactorily.
• Business, operations, clinical development plans and timelines, and supply chain could be adversely affected by health epidemics.
• Inability to obtain and maintain sufficient intellectual property protection for investigational products or infringement of others' intellectual property.

Future Outlook

Jasper Therapeutics expects to have results from the investigation into the problematic drug product lot in the coming weeks. The company plans to enroll an additional 10-12 patients in the affected multi-dose CSU cohorts, with data from these patients expected in Q4 2025. The commencement of the Phase 2b CSU study is now anticipated in mid-2026. The company will implement cost-cutting measures, including a potential restructuring, to extend its cash runway and reduce expenses.

Management Comments

• Ronald Martell, President and Chief Executive Officer of Jasper, stated: 'We were pleased that results from the 240mg and 360mg single dose cohorts continue to indicate that briquilimab treatment can lead to deep and durable disease control in patients with CSU.'
• Martell also commented: 'We are also very excited by the performance of the 180mg Q8W dose in the open label extension study with the strong efficacy observed, in combination with the encouraging safety data, supporting a differentiated profile.'
• Regarding the drug product issue, Martell said: 'While we are very disappointed by the confounded results seen in the two multi-dose cohorts of the BEACON study, we are currently investigating the cause and are taking steps to ensure that drug product from the lot in question is returned to the Company and that sites have drug product from other lots to continue dosing.'
• Martell added: 'We plan to enroll an additional 10-12 patients across the two impacted cohorts to inform final dose selection for the Phase 2b study, and will be implementing a number of cost cutting measures to reduce burn and extend our cash runway in light of this delay.'

Industry Context

This announcement highlights the inherent risks in clinical-stage biotechnology, where drug product quality and trial outcomes can significantly impact development timelines and strategic focus. Briquilimab, as a KIT (CD117) targeting antibody, aims to address mast cell-driven diseases like CSU, a market with existing treatments (e.g., omalizumab) but still a need for highly effective and well-tolerated options. The decision to halt asthma and SCID programs to focus resources on CSU indicates a strategic prioritization in response to clinical challenges and financial constraints, a common occurrence in the competitive biopharmaceutical landscape.

Comparison to Industry Standards

• The complete response rates of 89% in single-dose cohorts (240mg and 360mg) and 73% in the 180mg Q8W open-label extension for CSU are strong, particularly when compared to existing therapies like omalizumab (Xolair), which typically achieves complete response rates in CSU ranging from 30-50% in clinical trials, though direct head-to-head comparisons are not available.
• The rapid onset of clinical response (78% achieving response by week 2 in single-dose cohorts) suggests a potentially faster therapeutic effect than some current CSU treatments.
• The favorable safety profile with no Grade 3 or higher treatment-related adverse events and manageable neutrophil count decreases positions briquilimab as potentially differentiated in terms of tolerability compared to therapies with more significant systemic side effects.
• The drug product lot issue, however, represents a significant setback, impacting data integrity and leading to program halts, which is a critical operational challenge that can delay market entry and increase development costs, similar to manufacturing or quality control issues faced by other pharmaceutical companies during clinical development.

Stakeholder Impact

• Shareholders: Potential negative impact due to clinical trial delays, program halts, and the need for cost-cutting measures, which could affect future valuation and dilution if a capital raise becomes necessary.
• Patients (CSU): Continued hope for a new, effective treatment, but delays in the Phase 2b study mean a longer wait for potential market availability.
• Patients (Asthma/SCID): Disappointment as development programs for briquilimab in these indications have been halted.
• Employees: Potential impact from restructuring and cost-cutting measures, which could include workforce reductions.
• Clinical Sites/Investigators: Will receive new drug product and enroll additional patients, requiring continued operational coordination.

Next Steps

• Investigation of the problematic drug product lot (Lot A34954) is ongoing, with results expected in the coming weeks.
• New drug product will be provided to clinical sites to transition affected patients.
• Enrollment of an additional 10-12 patients across the 240mg Q8W and 240mg followed by 180mg Q8W cohorts to gather robust data.
• Data from these additional BEACON patients is expected in Q4 2025.
• Commencement of the Phase 2b CSU study is expected in mid-2026.
• Implementation of cost-cutting measures, including a potential restructuring, to extend cash runway and reduce expenses.
• Host a conference call and webinar on July 7, 2025, at 8:30 a.m. EDT to present updated data and program updates.

Key Dates

Recommendation

Keywords

Jasper Therapeutics, JSPR, Briquilimab, Chronic Spontaneous Urticaria, CSU, BEACON study, Clinical trial data, Drug product lot issue, Asthma, SCID, Biotechnology, Clinical stage, Mast cell diseases, KIT inhibitor, Antibody therapy, UAS7, Serum tryptase, Phase 1b/2a, Open-label extension, Corporate restructuring, SEC filing, 8-K