Jasper Therapeutics reports updated data from BEACON study

The BEACON study is a randomized, double-blind, and placebo-controlled Phase 1b/2a trial evaluating multiple ascending doses of subcutaneous briquilimab as a therapy for adult patients with moderate to severe CSU despite treatment with high dose antihistamines. The primary endpoints are safety and tolerability of briquilimab and secondary endpoints are focused on clinical activity and PK/PD, including measurement of serum tryptase and mast cells in skin. Primary measurements used to assess clinical activity were the sum of the Hives Severity Score and the daily Itch Severity Score, as measured via the Urticaria Activity Score over 7 days on a 0 to 42-point scale. The open-label extension study in chronic urticarias is enrolling participants from the BEACON study as well as the SPOTLIGHT study in CIndU upon completion of their initial follow up period. Participants in the open-label extension are treated with 180mg of briquilimab on a Q8W dosing schedule. The updated data, as of July 3, 2025, includes the results from 20 additional patients treated with briquilimab in the BEACON study, including 2 additional participants at 240mg single dose, 6 at 240mg Q8W, 7 at 240mg followed by 180mg Q8W, and 5 at 360mg single dose, as well as from 11 participants enrolled in the open label extension study at 180mg Q8W, all of whom completed at least 12 weeks of follow-up following initial dosing with investigational product. Substantial reductions in UAS7 scores were reported with a mean change from baseline at 4 weeks of 28.3 points in the 240mg single-dose cohort and 22.9 points in the 360mg single-dose cohort. Complete responses were achieved by 5 of 5 of participants treated in the 240mg single-dose cohort and 3 of 4 participants treated in the 360mg single dose cohort and 7 of 9 maintained well controlled disease through 8 weeks. Briquilimab treatment also resulted in deep and durable disease control in the open label extension study evaluating briquilimab at 180mg Q8W, with 8 of 11 participants achieving complete response at the week 12 assessment. Substantial reductions in tryptase were observed as early as the week 1 assessment and were correlated with the onset of clinical responses. Tryptase levels below the lower limit of quantification were reported for 8 of 10 participants across the 240mg and 360mg single dose cohorts. Briquilimab continued to be well tolerated in the BEACON study, as well as the open label extension, with no dose limiting toxicities observed. Safety observations potentially related to KIT blockade were infrequent and generally limited to low grade events, none of which resulted in discontinuations or dose delays and the majority of which resolved during repeat dosing. Mild and predictable decreases in neutrophil counts were observed upon dosing, with counts generally recovering prior to subsequent dose and no association to fever or infection. All cases of neutrophil count reduction observed in the 240mg and 360mg single dose cohorts resolved while on study with a median time to resolution of 42 days.