BioCryst Pharmaceuticals announced the dosing of the first subject into ZENITH-1, a clinical trial studying up to three dosage strengths of a liquid formulation of BCX7353 given as a single oral dose for the acute treatment of angioedema attacks in patients with hereditary angioedema (HAE).

"We are excited to launch the ZENITH-1 exploratory phase II trial. Based upon pharmacokinetic and pharmacodynamic properties of BCX7353, we believe it could be an efficacious and convenient oral alternative to parenteral treatments of acute angioedema attacks in patients with HAE. A liquid formulation of BCX7353 would be a strong complement to our prophylactic treatment program," said Jon Stonehouse, Chief Executive Officer. "We believe this new formulation can fill an unmet need for patients who are looking for better and easier ways to manage their illness.”

ZENITH-1 is a randomized, double-blind, placebo-controlled, adaptive dose-ranging trial of the efficacy, safety and tolerability of BCX7353 for treatment of acute angioedema attacks, and will enroll up to 60 subjects with HAE. Blinded study drug will be dosed as an oral liquid after onset of symptoms, for up to three attacks in each subject, with each subject receiving both BCX7353 (for two attacks) and placebo (for one attack) in a randomized sequence. The trial is structured with up to three consecutive cohorts testing single doses of 750mg (from 12 to 36 subjects), 500 mg (up to 12 subjects) and 250 mg (up to 12 subjects), starting with 750 mg. Efficacy assessments include patient-reported composite visual analogue scale (VAS) scores, patient global assessment, change in symptoms, and use of rescue medication.

Treatment effect will be assessed on accumulating results, beginning after 12 subjects have completed study in the first cohort (750mg), by comparing the proportion of BCX7353-treated and placebo-treated attacks which have a stable or improved composite VAS at 4 hours post dose. Once a treatment effect is demonstrated, enrollment at the 500mg dose level will commence. If treatment effect at the 500mg dose level is similar to 750mg dose level, the 250mg dose cohort will be enrolled.