FDA Approves New Drug for Hereditary Angioedema

Yael Waknine

August 25, 2011

August 25, 2011 — The US Food and Drug Administration (FDA) has approved icatibant subcutaneous injection (Firazyr, Shire Human Genetic Therapies, Inc) for the treatment of acute attacks of hereditary angioedema (HAE) in adults aged 18 years and older.

Icatibant, a bradykinin B2 receptor antagonist, is supplied in a prefilled syringe that can be stored at room temperature (up to 77°F) for portability and immediate use.

"Firazyr provides a new option to treat acute attacks of HAE and because it can be self-administered through an injection in the abdominal area, patients can treat themselves upon recognition of an HAE attack," said Curtis Rosebraugh, MD, MPH, director of the Office of Drug Evaluation II in the FDA's Center for Drug Evaluation and Research, in an agency news release.

FDA approval was based on data from 3 randomized, double-blind controlled clinical trials (FAST 1, 2, and 3) of a total of 223 patients, showing that a dose of 30 mg icatibant significantly decreased the median time to symptom relief, relative to placebo.

Data from the FAST 3 study (n = 98) showed a significant decrease in median time to a 50% decrease in symptoms for patients with cutaneous or abdominal attacks compared with placebo (2.0 hours vs 19.8 hours; 95% confidence interval, 6.1 - 26.3 hours; P < .001), as well as a significant decrease in median time to almost complete symptom relief (8.0 vs 36.0 hours). Use of additional rescue mediations was likewise significantly reduced (7% vs 40%).

These findings were corroborated by a meta-analysis of data from all 3 FAST trials, showing that patients treated with icatibant experienced a 50% reduction from baseline symptoms during a median time of 2.0 to 2.3 hours. This interval did not vary with repeated treatment for the first 5 HAE events, the majority of which (93%) were resolved with a single dose. Efficacy did not vary with laryngeal vs nonlaryngeal sites of attack, nor with patient vs clinician administration of medication.

Treatment-emergent adverse events most commonly included injection site reactions (97%). Other adverse events that occurred more than 1% of patients were fever, transaminase increase, dizziness, and rash.

As a condition of approval, the FDA has stipulated the distribution of patient counseling information that includes injection instructions.

Icatibant is already approved in 38 countries worldwide, including member states of the European Union.

As reported by Medscape Medical News, 2 other agents were previously approved by the FDA in 2009 for the treatment of HAE: a plasma-derived C1-esterase inhibitor concentrate for injection (Berinert, CSL Behring, Inc) for the treatment of adults and adolescents with HAE-related acute abdominal attacks and facial swelling, and ecallantide subcutaneous injection (Kalbitor, Dyax Corp) for the treatment of sudden and potentially fatal fluid build-up associated with HAE in patients aged 16 years and older.

HAE, a rare genetic disorder linked to a defect in the C1-esterase inhibitor protein, is characterized by relapsing, self-limiting episodes of edema that occur primarily in the extremities, intestinal tract, face, and larynx. Abdominal symptoms include severe pain, nausea, vomiting, cramps, and diarrhea; attacks that involve the face and throat can result in airway obstruction, asphyxiation, and death if left untreated. Fewer than 30,000 individuals in the United States have HAE.

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