BCX7353 is an investigational therapy being developed by BioCryst Pharmaceuticals for patients with hereditary angioedema (HAE).

The medicine is available in two formulations: an oral capsule as a preventive treatment to avoid angioedema attacks, and as an oral liquid for the treatment of acute HAE.

How BCX7353 works

HAE is a rare inherited disease in which mutations in the C1 inhibitor, a protein involved in the immune response, lead to excessive production of bradykinin. This inflammatory mediator, or molecule, that promotes inflammation regulates blood pressure and inflammation by encouraging small blood vessels to dilate (widen). Excessive bradykinin leads to angioedema and pain.

BCX7353 is an oral antagonist of plasma kallikrein, a precursor of bradykinin. By inhibiting plasma kallikrein, BCX7353 is thought to reduce the amount of bradykinin in HAE patients, potentially treating and preventing angioedema attacks.

BCX7353 in clinical trials

The effectiveness, safety, tolerability, pharmacokinetics (movement in the body), and pharmacodynamics (effect on the body) of BCX7353 were first evaluated in a Phase 2 clinical trial (NCT02870972). The study, called APeX-1, aimed to assess the preventative potential of the medicine to reduce the frequency of attacks in people with HAE. The results of the trial, published in the scientific journal Annals of Allergy, Asthma & Immunology, showed that BCX7353 was generally safe, well-tolerated, and associated with a significant reduction in HAE attacks.

BioCryst is recruiting patients for three new clinical trials assessing BCX7353. APeX-2, a Phase 3, placebo-controlled trial (NCT03485911) is designed to evaluate the effectiveness and safety of oral BCX7353 in preventing acute angioedema attacks in patients with type 1 and type 2 HAE. The primary goal of the trial is to determine BCX7353’s ability to reduce the frequency of angioedema attacks after 24 weeks of treatment. According to the company, the first patient has been treated and enrollment continues for up to 100 participants in 14 different centers across the U.S. It is expected that the results of the study will be announced in the first half of 2019.

A Phase 2/3 trial, ApeX-S (NCT03472040), will test the long-term clinical ability of BCX7353 as a preventive treatment for HAE patients. Participants will receive one of two doses of BCX7353 (110 mg or 150 mg) once a day for 48 weeks. The researchers then will assess the long-term safety and effectiveness of the treatment on patients’ quality of life, as well as the durability of any response.

The trial aims to enroll up to 160 patients in Austria, Denmark, the U.K., Germany, and Macedonia. Patients who already had participated in a previous BCX7353 trial will have priority, followed by those who have never had BCX7353 therapy.

ZENITH-1, a proof-of-concept Phase 2 clinical trial (NCT03240133), will study up to three doses of liquid BCX7353 as a treatment for acute angioedema attacks in patients with HAE. Researchers will evaluate the effectiveness of the different doses of BCX7353 by assessing the patient-reported composite visual analog scale scores (a test for gauging pain intensity), patients’ global assessment, any change in symptoms, and the use of rescue medication. The first patient in the trial already has been dosed. Enrollment continues for up to 60 participants across 11 countries in Europe. The trial is expected to be completed in November 2018.


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