BioCryst says oral drug works for HAE attacks

BioCryst Pharma says its oral drug BCX7353 was effective in treating acute hereditary angioedema (HAE) attacks in a midstage trial, setting up a possible registration study as an alternative to current injectable or intravenous therapies.

At the highest of three doses tested, the plasma kallikrein inhibitor—given as a one-off oral treatment—was superior to placebo against “the majority of efficacy endpoints” in the study, including improvements in symptoms and reduced use of rescue medications. Shares in the company rose more than 6% premarket on the update.

The data from patients in the 750mg cohort of the ZENITH-1 trial shows that BioCryst’s drug started to work on symptoms within an hour of dosing in some cases, with its effects sustained throughout 24 hours, says the biotech. Standard medication use was reduced by 31.6% with BCX7353 compared to placebo, and zero or mild symptoms after dosing were reported in 64.1% of patients on the drug and 32.3% of the control group.

Data from two lower-dose groups (250mg and 500mg) are due next year, but BioCryst says it is encouraged by the results, which could lead to a “future registration trial for the acute treatment of HAE attacks.” The biotech is also developing BCX7353 as a maintenance therapy to prevent HAE attacks, and reported positive data from a second phase 2 trial of the drug in this indication earlier this year.

HAE is a rare genetic disease caused by deficiency of a plasma protein called C1-esterase inhibitor that affects approximately 6,000 to 10,000 people in the U.S. and causes rapid swelling of the hands, feet, limbs, face, intestinal tract or airway that can be life-threatening. Six drugs have been approved by the FDA for treating or preventing HAE attacks since 2008.

At the moment, CSL Behring’s Berinert and Pharming’s Ruconest—both intravenously administered C1-inhibitor concentrates—and Shire’s subcutaneous duo of B2 bradykinin receptor antagonist Firazyr and kallikrein inhibitor Kalbitor are approved to treat acute HAE attacks.

“ZENITH-1 represents a groundbreaking study, as the first clinical trial to demonstrate effective treatment of acute HAE attacks with an oral therapy,” according to principal investigator Hilary Longhurst M.D., Ph.D., of Addenbrookes Hospital in Cambridge, U.K.

“The observed effect of BCX7353 within one hour of dosing and the substantial reduction in rescue medication use compared to placebo suggest that BCX7353 has outstanding potential to offer physicians and patients an urgently needed new oral therapy option,” she added.