KalVista Pharmaceuticals, Inc. (Nasdaq: KALV) today announced new setralstat findings related to time to end of progression of hereditary angioedema (HAE) attacks, and the effectiveness of treatment of attacks considered the most debilitating by patients, mucosal attacks, and attacks that have progressed in severity after a treatment delay. These data were presented at two congresses taking place concurrently: the 14th C1-inhibitor Deficiency & Angioedema Workshop in Budapest, Hungary, and the Eastern Allergy Conference (EAC) in Palm Beach, Florida, from May 29–June 1, 2025.
Time to End of Progression of Hereditary Angioedema Attacks Treated with Sebetralstat was presented by William Lumry, M.D., Clinical Professor of Internal Medicine at the University of Texas Southwestern Medical School in Dallas and Director at Allergy and Asthma Research Associates, Dallas, Texas, United States.
- Time to end of attack progression (n=1591 attacks) in KONFIDENT-S: median 19.8 minutes
- Results from the open-label extension (KONFIDENT-S) aligned closely with the pivotal phase 3 trial, KONFIDENT, reinforcing the rapid effect of sebetralstat after absorption
“Stopping the progression of an HAE attack as early as possible is paramount to mitigating its impact on patients,” said Dr. Lumry. “In both the KONFIDENT and KONFIDENT-S studies, sebetralstat halted attack progression in a median time of 19.8 minutes. As prior data have demonstrated near-complete plasma kallikrein inhibition 15 minutes after treatment, this analysis reveals that attacks are halted minutes after absorption. The consistency of findings across the KONFIDENT and KONFIDENT-S trials underscores the potential of sebetralstat as an effective and rapid-acting on-demand treatment for HAE attacks.”
Effectiveness of sebetralstat for the on-demand treatment of mucosal hereditary angioedema attacks: interim analysis from KONFIDENT-S was presented by Henriette Farkas, M.D., PhD, DSc, Professor of Allergology and Clinical Immunology at Semmelweis University and Head of the Hungarian Angioedema Center of Reference and Excellence, Budapest, Hungary.
- Patients were able to self-administer sebetralstat quickly, with a median time to treatment of 20 minutes for abdominal attacks and 11.5 minutes for laryngeal attacks
- The median time to beginning of symptom relief was 1.3 hours for both abdominal and laryngeal attacks
- Of attacks reaching symptom relief within 12 hours, 96% did so before or without the need for an additional sebetralstat administration
- Sebetralstat was well-tolerated, even in laryngeal attacks, with no reported difficulties swallowing the oral tablet
“Mucosal HAE attacks, particularly those affecting the larynx, are a significant concern for patients and clinicians due to the risk of rapid progression and severe consequences, including the possibility of asphyxiation if left untreated,” said Dr. Farkas. “These interim data from KONFIDENT-S demonstrate that sebetralstat provided rapid relief and resolution of both abdominal and laryngeal attacks with a favorable safety profile. Patients were able to self-administer sebetralstat very early in the course of an attack, when most attacks were still mild or moderate in severity.”
Effectiveness of Sebetralstat for Severe or Very Severe Hereditary Angioedema Attacks in KONFIDENT-S was presented by H. Henry Li, M.D., Director of Immunology at the Institute for Asthma and Allergy, Wheaton, Maryland, United States.
- Sebetralstat was used to treat 76 attacks that had progressed to severe or very severe after a median of 2.16 hours from attack onset, demonstrating its utility in more advanced stages of HAE attacks
- The median time to beginning of symptom relief for these attacks was 1.36 hours, with reduction in attack severity and substantial reduction of symptom burden in a median of 1.77 hours and 9.15 hours, respectively
“When attacks are not treated early in accordance with guidelines, they can escalate and become severe,” said Dr. Li. “We conducted this analysis of KONFIDENT-S to assess the utility of sebetralstat in more advanced stages of attacks that were associated with delayed treatment. Sebetralstat delivered symptom relief in a median time of 1.36 hours, reinforcing its potential as an on-demand treatment for challenging attack scenarios.”
“These new data underscore the potential of sebetralstat to fundamentally change HAE attack management,” stated Paul Audhya, M.D., MBA, Chief Medical Officer of KalVista. “Even in real-world, high-stakes scenarios—be it mucosal attacks or severe attacks due to delayed treatment—sebetralstat consistently delivered rapid and reliable relief. The uniformity of these results, paired with an oral tablet formulation, solidifies our belief that sebetralstat can empower patients to act swiftly and recover quickly. We remain committed to bringing this innovative therapy to the HAE community as quickly as possible.”
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