KalVista Pharmaceuticals Shares Response Drivers in Sebetralstat Placebo-controlled Clinical Trials

Analysis shows sebetralstat 600 mg achieved symptom relief sooner than placebo, regardless of time to treatment, attack location, or severity

Published on Feb. 27, 2026

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KalVista Pharmaceuticals presented an analysis of data from phase 2 and phase 3 clinical trials of sebetralstat, an oral plasma kallikrein inhibitor for on-demand treatment of hereditary angioedema (HAE) attacks. The analysis found that the likelihood of symptom relief was achieved sooner with sebetralstat 600 mg compared to placebo, regardless of the time to treatment administration, attack location, or baseline severity. Model-based simulations showed that a single dose of sebetralstat 600 mg had a high probability of providing symptom relief within 12 hours, with the earliest relief achieved when the medication was taken within 30 minutes of attack onset.

Why it matters

This analysis provides important insights into the factors that predict the efficacy of sebetralstat, a newly approved oral treatment for HAE attacks. The finding that sebetralstat works well across different attack characteristics suggests it could be a valuable on-demand option for patients, who often need fast-acting relief during unpredictable and potentially life-threatening HAE episodes.

The details

The analysis utilized parametric time-to-event modeling to evaluate the impact of factors such as time to treatment, attack location, and baseline severity on the time to beginning of symptom relief with sebetralstat 600 mg versus placebo. The Gompertz probability distribution was used to describe the hazard function. The results showed that regardless of the time to treatment administration, the likelihood of symptom relief was achieved sooner with sebetralstat 600 mg than placebo. Additionally, the probability of symptom relief following sebetralstat 600 mg treatment was similar regardless of attack location, baseline severity, and number of doses. Model-based simulations predicted that a patient who administers 1 dose of sebetralstat 600 mg within 30 minutes, 30-60 minutes, or after 60 minutes of attack onset would have a probability of experiencing symptom relief within 12 hours of 88.5%, 81.9%, and 84.4%, respectively.

  • The phase 2 and phase 3 clinical trials of sebetralstat were conducted between 2023 and 2025.

The players

KalVista Pharmaceuticals

A pharmaceutical company that developed sebetralstat, an oral plasma kallikrein inhibitor for the on-demand treatment of hereditary angioedema (HAE) attacks.

Jonathan A. Bernstein

A researcher from the University of Cincinnati College of Medicine and Bernstein Clinical Research Center who was involved in the analysis.

Emel Aygören-Pürsün

A researcher from the University Hospital Frankfurt, Goethe University Frankfurt who was involved in the analysis.

Danny M. Cohn

A researcher from the Amsterdam University Medical Center, University of Amsterdam who was involved in the analysis.

Henriette Farkas

A researcher from the Hungarian Angioedema Center of Reference and Excellence, Department of Internal Medicine and Hematology, Semmelweis University who was involved in the analysis.

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What they’re saying

“The model suggests earlier time to treatment associates with an earlier likelihood of achieving symptom relief with sebetralstat 600 mg”

— Jonathan A. Bernstein, Researcher (Presented at the American Academy of Allergy, Asthma and Immunology Annual Scientific Meeting)

“As an oral treatment, sebetralstat enables early administration, which was the strongest predictor of symptom relief”

— Marc A. Riedl, Researcher (Presented at the American Academy of Allergy, Asthma and Immunology Annual Scientific Meeting)

The takeaway

This analysis of the sebetralstat clinical trials highlights the importance of early treatment for achieving symptom relief in HAE attacks. The findings suggest sebetralstat 600 mg could be an effective on-demand option for patients, as it appears to work well regardless of attack characteristics. The high probability of symptom relief within 12 hours, especially with early administration, makes sebetralstat a potentially valuable new treatment for this unpredictable and serious condition.