BioCryst Pharmaceuticals Inc.'s medicine BCX7353 reduced skin-swelling attacks in patients with hereditary angioedema, achieving the main goal of a late-stage study.
The Durham, N.C.-based company's stock, however, was down by 46.96% to $3.92 on the Nasdaq as of 10:27 a.m. ET.
BioCryst evaluated once-daily oral BCX7353 against placebo in a phase 3 trial, dubbed APeX-2, to prevent angioedema attacks in patients with the hereditary version of the disease.
Hereditary angioedema is a disease characterized by recurrent attacks of severe swelling of the skin and mucous membranes. The most common areas of the body to develop swelling are the limbs, face, intestinal tract and airway.
The trial enrolled 121 patients in the U.S., Canada and Europe. Patients were divided into three groups. One group received a 110-milligram dose of BCX7353 while the other received 150 milligrams. The third group received a placebo.
The company said that after 24 weeks of treatment, the 150-milligram dose reduced the attack rate in patients by 44% compared to placebo. About 50% of patients receiving the 150-milligram dose had a more than 70% reduction in their attack rate, compared to when treatment began. About 15% of patients on placebo saw a similar reduction in their attack rate.
The company said that the 110-milligram dose of BCX7353 reduced the attack frequency by 30% compared to placebo.
BioCryst added that both doses of BCX7353 were generally safe and well-tolerated, and no drug-related serious adverse events were reported.
CEO Jon Stonehouse said BCX7353 is "positioned to become a front-line therapy option."
Analysts have previously suggested that the drug would need to reduce the attack rate in patients by at least 50% to compete against the injectable rivals already on the market, Endpoints News reported. Shire PLC's injectable medicine Takhzyro, or lanadelumab-flyo, which was approved by the U.S. Food and Drug Administration in August 2018, reduced the angioedema attack rate by 87% compared to placebo in its phase 3 trial.
BioCryst plans to submit an application for BCX7353 to the FDA in the fourth quarter and to the European Medicines Agency in the first quarter of 2020.