KalVista Announces New Data from Sebetralstat Clinical Trials

KalVista announced new data from its sebetralstat clinical trial program presented at the American Academy of Allergy, Asthma & Immunology annual meeting and the Western Society of Allergy, Asthma & Immunology 63rd Annual Scientific Session. As of July 9, 2025, 2,464 HAE attacks were treated with sebetralstat. Across the first 30 attacks for participants: The use of a second dose occurred in 19.3% of attacks and showed a decreasing trend from the first through the thirtieth attack. The use of conventional injectable treatments within 12 hours occurred in only 5.1% of attacks and also showed a decreasing trend with repeated sebetralstat use. Patient satisfaction remained consistently high throughout the study, with 83.1% of sebetralstat-treated attacks rated as satisfied or better on a seven-point scale. Across a total of 2,077 HAE attacks reported as of September 14, 2024, 98.1% were treated using either oral sebetralstat or conventional injectable on-demand treatment. Only 1.9% of attacks were left untreated. Participants chose to treat the majority of attacks with sebetralstat, indicating strong preference regardless of attack severity or location. Nearly all reported attacks were treated, a markedly higher rate than typically observed in real-world HAE studies, suggesting that access to an oral treatment option may increase willingness to treat, including mild attacks. Use of conventional on-demand treatments decreased from 21% to 13% across the first five attacks treated by participants, while sebetralstat use increased from 76% to 85%, indicating a growing shift and preference for oral sebetralstat despite having access to injectable options. Across analyses, treating HAE attacks within 30 minutes of onset was the strongest predictor of achieving earlier symptom relief with sebetralstat. Factors such as attack location, baseline severity and dose did not meaningfully improve the predictive model as significantly as time to treatment. Simulations suggested that early use of oral sebetralstat could provide symptom relief for nearly 90% of subjects within 12 hours.