FDA Grants Priority Review to C1 Esterase Inhibitor for HAE

The PDUFA date has been set for June 20. In a previous trial of 22 patients, those on the Shire product reported a mean of 6.1 attacks compared with 12.7 with placebo

The US Food and Drug Administration (FDA) has approved the filing of a supplemental Biologics License Application (sBLA) and granted a Priority Review Designation to a C1 esterase inhibitor (Cinryze, Shire) for the treatment of hereditary angioedema (HAE) in children aged 6 years and older.

The FDA is anticipating a Prescription Drug User Fee Act action date of June 20. If approved, it would become the only C1 esterase inhibitor therapy with an indication including childhood and adulthood. Shire is the only drug developer thus far that has completed a study for prophylaxis of hereditary angioedema.

“Adults and adolescents living with [hereditary angioedema] have used CINRYZE to help reduce the frequency and severity of attacks for nearly a decade,” Jennifer Schranz, MD, the global development lead in hereditary angioedema at Shire, said in a statement. “Shire committed to studying the safety and efficacy of our [hereditary angioedema] therapies in children aged 6 years and older because we understand the importance of this work to families in the [hereditary angioedema] community. We look forward to working closely with the FDA in the coming months on this important review.”

A decision about the therapy will be made based on data from 2 open-label studies, LEVP 2006-1 and LEVP 2006-4, as well as 2 trials on pediatric patients (0624-203 and 0624-301) which only evaluated the therapy as prophylaxis.

In a previous trial of 22 patients, those on the Shire product reported a mean of 6.1 attacks compared with 12.7 with placebo (P <.0001). The average duration of the attacks for those in the C1 esterase inhibitor group was 2.1 days compared to 3.4 days in the placebo group (P <.01), and the treatment group experienced a 66% overall reduction in days of swelling (P <.0001).

The primary outcome of the trial was the number of attacks patients experienced while taking Shire’s C1 esterase inhibitor compared to placebo. While the Shire product did reduce the number of attacks, the response to the drug varied. Of the 22 patients who participated in the trial, 20 had fewer attacks, of which 4 had no attacks, but 2 had an increased number of attacks.

Shire’s C1 esterase inhibitor currently services a large portion of the patients with the condition—an estimated 1 in 10,000 to 1 in 50,000 are affected. The therapy was originally approved in late 2008 for use as prophylaxis against attacks of swelling in adults and adolescents with hereditary angioedema.

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