By Connor Hart

Shares of Jasper Therapeutics rose after the company disclosed what it called positive data from a recent trial of its treatment for chronic mast cell diseases.

The stock climbed 13%, to $6.32, in premarket trading Monday. Through Friday's close, shares have lost more than three-quarters of their value in the past year.

The Redwood City, Calif., biotechnology company on Friday said it would present new data from a Phase 1b/2a study of briquilimab, its novel treatment for cell-driven diseases such as chronic spontaneous urticaria, chronic inducible urticaria and asthma.

The company, which said it will hold a conference call Monday morning to discuss results of the study, said administration of the therapy resulted in deep disease control at a dose of 180 mg, with all participants enrolled in the cohort achieving a clinical response within the 8-week preliminary analysis period.

Jasper said the treatment's efficacy was rapid and durable, as two-thirds of participants achieved clinical response by week 2, and more than half maintained clinical response through week 8.

The treatment continues to be well tolerated, with no serious adverse events reported in the study, the company said.

Chief Executive Ronald Martell said the company was very pleased with the updated results of the study. He said the results, combined with those of previous studies, "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."

Write to Connor Hart at connor.hart@wsj.com

(END) Dow Jones Newswires

June 16, 2025 07:07 ET (11:07 GMT)

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