FDA Approves Drug to Prevent Hereditary Angioedema Attacks

C1 esterase inhibitor (Haegarda) may prevent swelling attacks associated with hereditary angioedema.

The FDA recently approved C1 esterase inhibitor (human) (Haegarda) for subcutaneous injection to prevent hereditary angioedema (HAE) attacks. The drug is indicated to be injected twice weekly.

Subcutaneous administration allows for in-home injection by a patient after receiving proper training, according to a press release. The drug works by replacing deficient or dysfunctional C1-INH and restoring plasma protein levels above normal levels to reduce the risk of HAE attacks.

HAE is caused by dysfunctional or deficient C1-esterase inhibitor (C1-INH)—a plasma protein— and is characterized by rapid swelling of the hands, feet, limbs, face, intestinal tract, or airway. HAE swelling attacks can be triggered spontaneously or by stress, surgery, and infection, the FDA reported. This rare disease affects 6000 to 10,000 patients in the United States.

"The approval of Haegarda provides a new treatment option for adolescents and adults with Hereditary Angioedema," said Peter Marks, MD, PhD, director of FDA’s Center for Biologics Evaluation and Research. "The subcutaneous formulation allows patients to administer the product at home to help prevent attacks."

C1 esterase inhibitor is derived from human plasma that has been purified, pasteurized, freeze-dried, and concentrated. While the drug has been approved to prevent HEA attacks, it cannot treat onset of an HAE attack, the FDA warned.

The approval is based on positive findings from a clinical trial that included 90 patients with HAE aged 12 to 72 years. Patients were randomized to receive subcutaneous doses of either 40-IU/kg or 60-IU/kg of C1 esterase inhibitor or placebo.

Over 16 weeks, the investigators found that patients treated with C1 esterase inhibitor were found to have a significant reduction in HAE attacks compared with placebo, according to the release.

The most common side effects reported in the study were injection site reactions, hypersensitivity reactions, nasopharyngitis, and dizziness.

The FDA cautions that patients who have experienced life-threatening allergic reactions to a C1-INH preparation or its inactive ingredients should not be treated with C1 esterase inhibitor.

C1 esterase inhibitor was previously granted orphan drug designation.

“The FDA approval of HAEGARDA is an important milestone for the HAE community because it addresses the primary need of patients: to effectively prevent debilitating HAE attacks,” said Andrew Cuthbertson, chief scientific officer and R&D director, CSL Limited. “CSL Behring has a long heritage in HAE, and thanks to our clinical trial participants, we’re proud to lead the community into the next era of treatment by offering the first and only subcutaneous preventive treatment option.”