Jasper Therapeutics, Inc. (Nasdaq: JSPR) (Jasper), a clinical stage biotechnology company focused on development of briquilimab, a novel antibody therapy targeting c-Kit (CD117) to address mast cell driven diseases such as chronic spontaneous urticaria (CSU), chronic inducible urticaria (CIndU) and asthma, announced that the first patient has been dosed in Jasper’s Phase 1b/2a clinical challenge study evaluating briquilimab in allergic asthma, called ETESIAN (Evaluating The Efficacy and Safety of briquilimab In participANts with allergic asthma). The ETESIAN study is evaluating a single administration of subcutaneous briquilimab in patients with asthma.

“Dosing of the first patient in our ETESIAN study in asthma is a significant milestone, marking our third clinical program evaluating briquilimab in an inflammatory disease driven by unwanted mast cell activity,” said Edwin Tucker, M.D., Chief Medical Officer of Jasper. “Following dose escalation through Part 2 of the BEACON study in CSU, we obtained regulatory clearance to move directly to a subcutaneous 180mg dose in the ETESIAN study, which we believe will drive deep mast cell depletion in the airways and enable durable clinical benefit for patients with asthma. We look forward to providing enrollment updates as we progress through the study and anticipate reporting the initial data in the second half of 2025.”

The Phase 1b/2a ETESIAN study is a single dose double-blind, placebo-controlled challenge study that is expected to enroll approximately 30 patients across as many as 7 sites in Canada with a key objective of demonstrating proof-of-concept in asthma utilizing a potential therapeutic dose to inform future trials in the broader asthma population. The study will be conducted utilizing a single 180mg dose of subcutaneous briquilimab and key assessments will include both early and late asthmatic response, changes in airway hyperresponsiveness, mast cell depletion and recovery, and safety.

“Depletion of mast cells via inhibition of c-Kit is a novel mechanism with the potential to alleviate asthmatic response in patients underserved by existing therapies,” said Paul O’Byrne, M.D., Professor, Dean and Vice President of the Faculty of Health Sciences at McMaster University. “As a potent and targeted c-Kit inhibitor, I believe briquilimab has the potential to overcome the safety issues that have limited development of other c-Kit inhibiting agents and, in turn, serve as an important treatment option for patients suffering from asthma. I look forward to enrolling patients into the ETESIAN study.”