New Boxed Warning for BoNT Products; FDA Approves Dysport

Subject: New Boxed Warning for BoNT Products; FDA Approves Dysport

Date: 5/12/2009

The United States Food and Drug Administration (FDA) has ordered that the manufacturers of Botox® and Myobloc® add a boxed warning to the prescribing information for each product about the potential for serious side effects at sites distant from injection. The FDA also ordered the manufacturers to develop a Risk Evaluation and Mitigation Strategy, and to submit safety data on injections in children for treatment of spasticity.

In a separate action, the FDA approved DysportTM for treatment of cervical dystonia and glabellar lines. The same additional labeling and monitoring requirements will apply to Dysport.

New Labeling and Safety Monitoring
According to an Update from the Center for Drug Evaluation and Research at the FDA, the new requirements follow an ongoing safety review, which identified case reports of serious adverse events and deaths following treatment for spasticity and cervical dystonia.

Pediatric cases involved treatment for spasticity and “were described as botulism, or involved symptoms including difficulty breathing, difficulty swallowing, muscular weakness, drooping eyelids, constipation, aspiration pneumonia, speech disorder, facial drooping, double vision, or respiratory depression. Serious case reports described hospitalizations involving ventilatory support and reports of death.” Adult cases were for spasticity or cervical dystonia, resulting in hospitalization and placement of a feeding tube or requirement for mechanical ventilation. “Although there were several deaths in adults, it is not possible to attribute them to the botulinum toxin because the patients also suffered from complications of their pre-existing conditions,” the report said.

The FDA recommends that healthcare professionals should understand that unit potency differs among the various BoNT products; should educate patients about the potential for adverse effects, including that onset may be hours or weeks after injection; and that patients should seek medical attention immediately if they develop symptoms.

Symptoms include “unexpected loss of strength or muscle weakness, hoarseness or trouble talking (dysphonia), trouble saying words clearly (dysarthria), loss of bladder control, trouble breathing, trouble swallowing, double vision, blurred vision and drooping eyelids.”

The REMS required of each manufacturer is to include a communication plan to increase knowledge of risks and non-interchangeability of products, and a medication guide to patients, families, and caregivers.

More information can be found in the FDA announcement:
www.fda.gov/Cder/drug/early_comm/botulinium_toxins200904.htm

Dysport Marketing Schedule
According to an Ipsen press release, Ipsen will market Dysport in the United States for cervical dystonia, and is expected to make it available in the second half of 2009. Medicis will market Dysport in the U.S. for glabellar lines, and is expected to do so within the next two months. Both products will be identified as “abobotulinumtoxinA,” to differentiate them from “other marketed botulinum toxin products.”