Phase III KONFIDENT trial meets all endpoints for sebetralstat as first oral on-demand therapy for hereditary angioedema

KONFIDENT was the largest and most representative trial ever conducted in HAE, and included adolescents, patients using long-term prophylaxis, and all attack severities and locations.

The clinical trial met all primary and key secondary endpoints and demonstrated a favorable safety profile. HAE attacks treated with both 300 mg and 600 mg of sebetralstat achieved the primary endpoint of beginning of symptom relief significantly faster than placebo (p<0.0001 for 300 mg, p="0.0013" for 600 mg). the median time to beginning of symptom relief was 1.61 hours with sebetralstat 300 mg (ci 1.28, 2.27), 1.79 hours with sebetralstat 600 mg (ci 1.33, 2.27) and 6.72 hours with placebo (ci 2.33,>12). Consistent with previous studies, sebetralstat was well-tolerated, with a safety profile similar to placebo. There were no patient withdrawals due to any adverse event and no treatment-related serious adverse events (SAEs) were observed. Treatment-related adverse event rates were 2.3% for 300 mg sebetralstat, 2.2% for 600 mg sebetralstat, and 4.8% for placebo.

“We are thrilled to announce positive phase III results for the KONFIDENT trial, which we believe position sebetralstat to become the first oral, on-demand therapy for the treatment of HAE. These clinically meaningful results represent a potentially significant advance for people living with HAE. If approved, sebetralstat may offer a compelling treatment option for patients and their caregivers given the long-standing preference for an effective and safe oral therapy that provides rapid symptom relief for HAE attacks,” said Andrew Crockett, Chief Executive Officer of KalVista.

Primary and key secondary endpoints were analyzed in a fixed, hierarchical sequence and adjusted for multiplicity. Key secondary endpoints showed: i. Attacks treated with sebetralstat 300 mg or 600 mg achieved a significantly faster time to a reduction in attack severity from baseline, compared to placebo (p=0.0036 for 300 mg and p=0.0032 for 600 mg). ii. Attacks treated with sebetralstat 300 mg or 600 mg demonstrated a significantly faster time to complete attack resolution, compared to placebo (p=0.0022 for 300 mg and p<0.0001 for 600 mg).

“These highly encouraging phase III results show that sebetralstat provided rapid symptom relief in a broad HAE population that reflects my clinical practice,” said Danny Cohn, MD, PhD, Department of Vascular Medicine, University of Amsterdam, and principal investigator for the KONFIDENT phase III trial. “If approved, sebetralstat could transform the management of HAE.”

“With no new on-demand therapies for HAE approved for nearly a decade, having a safe and effective oral, on-demand treatment for HAE attacks could be immensely valuable in addressing unmet needs and reducing the treatment burden associated with current injectable treatments,” said Marc A. Riedl, MD, professor of medicine and clinical director, U.S. Hereditary Angioedema Association Center at the University of California, San Diego, and an investigator for the KONFIDENT phase III trial. “Against the backdrop of patient needs and opportunities, the results of this trial with sebetralstat are extremely encouraging for the HAE community.”

The Company plans to present phase III data for the KONFIDENT trial at the annual meeting of the American Academy of Allergy Asthma and Immunology (AAAAI) on February 25, 2024.

About the KONFIDENT Phase III Trial; The KONFIDENT phase III trial was a randomized, double blind, event-driven, crossover clinical trial evaluating the efficacy and safety of sebetralstat 300 mg and 600 mg versus placebo for the on-demand treatment of HAE. The trial enrolled a total of 136 adult and adolescent HAE patients from 66 clinical sites across 20 countries, making it the largest clinical trial ever conducted in HAE. In the trial, patients treated each eligible attack with up to two doses of study drug, and each patient could treat up to three attacks over the course of the study. The trial included type 1 and type 2 HAE patients who had at least two attacks in 90 days prior to enrollment.