On Wednesday, Jasper Therapeutics, Inc. ( JSPR ) reported preliminary data from the ongoing BEACON Phase 1b/2a study of subcutaneous briquilimab in adult participants with chronic spontaneous urticaria (CSU).

Chronic spontaneous urticaria is defined by the presence of hives daily or almost daily for at least six weeks.

Also Read: Why Is Chronic Disease-Focused Jasper Therapeutics Stock Trading Higher On Monday?

The Urticaria Activity Score (UAS) assesses daily pruritus (itchy feeling) and the number of hives, which, when summed over a week, gives UAS7.

Substantial reductions in UAS7 were reported, with a mean change from baseline at 8 weeks of -26.6 in the 240mg (n=3) single-dose cohort and multiple dosing regimens at or above 120mg demonstrating UAS7 changes of more than -25 points.

Clinical responses were observed as early as one week after the first dose, and Complete Responses (UAS7 = 0) were achieved by patients at each therapeutic dose level (80mg, 120mg, 180mg, and 240mg). Most notably, all patients in the 240mg single-dose cohort maintained Complete Responses through the 8-week time point.

The durability of response was generally dose-dependent, and reductions in serum tryptase to levels below the lower limit of quantification were observed at multiple dose levels. Briquilimab was well tolerated in the study and had a favorable safety profile.

Tryptase levels below the lower limit of quantification were reported for 86% (6 of 7) of participants in the 180mg Q8W cohort at week 2 and for 100% (3 of 3) of participants in the 240 mg single-dose cohort at week 1.

Briquilimab was well tolerated in the study, with no dose-limiting toxicities observed.

Jasper expects to begin a registrational program in CSU, with a Phase 2b study expected to commence in the second half of 2025.

Additional data at 180mg Q8W from the open-label extension study, as well as further data from BEACON cohorts evaluating a 360mg single dose, a 240mg Q8W dose, and a 180mg Q8W dose following a 240mg loading dose, will inform the final selection of doses for the Phase 2 b study.

Data from these additional cohorts are expected to be presented by mid-2025.

William Blair reports that the top-line results show strong efficacy across different dose groups, possibly outperforming Celldex Therapeutics, Inc.’s barzolvolimab.

However, the 180 mg dose performed below expectations, and detailed data on key adverse events by dose level is missing. Analyst Matt Phipps believes more clarity on these issues could ease investor concerns, as the stock faced significant declines.

Price Action: JSPR stock is down 59% at $7.39 at the last check on Wednesday.

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