In February 2021, we reported positive results for a Phase 2 clinical trial demonstrating statistically and clinically significant responses for sebetralstat as an oral on-demand treatment for HAE attacks.
The sebetralstat Phase 2 was a randomized, double-blind, placebo-controlled, crossover clinical trial evaluating the efficacy and safety of sebetralstat as an on-demand treatment for hereditary angioedema (HAE) attacks. The trial completed 53 adult HAE patients from 25 clinical sites in the United States and Europe. The trial included type 1 and type 2 HAE patients who had three attacks in 90 days prior to enrollment. During the first part of the two-part trial, patients received a single, open label 600 mg dose of sebetralstat to evaluate pharmacokinetic and pharmacodynamic properties. All patients then entered part two of the trial, which was a double-blind investigation to assess the efficacy of sebetralstat compared to placebo in a two‑attack, crossover design. During part two of the trial, patients took a single dose of 600 mg of sebetralstat or placebo within one hour of the start of the first attack. The second attack was dosed with the alternative crossover treatment. Patients were able to use their conventional rescue treatment, as required.

Topline Phase 2 Results
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Time to use of conventional treatment within 12 h of study drug administration was significantly longer with sebetralstat versus placebo; (p=0·0010)
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Sebetralstat significantly reduced time to onset of symptom relief (p=<0.0001) on the Patient Global Impression of Change scale (PGI-C), with a median time of 1.6 hours versus 9 hours for attacks treated with placebo
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Time to conventional attack treatment use or worsening in severity by 1 level or more on the PGI-S, whichever came first, within 12 h of study administration was significantly longer after treatment with sebetralstat than after treatment with placebo (p<0.001)
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The median time to attack resolution, defined as a PGI-S rating of “none” within 24 h after study drug administration, was significantly shorter with sebetralstat than with placebo (p=0·0021)
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Sebetralstat was well-tolerated and no serious adverse events were reported. The proportion of drug-related treatment-emergent adverse events was similar in attacks treated with sebetralstat and placebo