Plaintiffs: Allergan Promoted Off-Label Use of Botox

In Orange County, California, opening statements began yesterday in a multi-plaintiff civil case against Allergan, maker of Botox. The plaintiffs, including the mother of a deceased 7-year-old Texas girl with cerebral palsy, argue that off-label use of the company's drug caused severe adverse reactions including death. Trial coverage is provided in frustratingly nonlinear stories from ABC News and the LA Times.

Piecing together the information, the case against Allergan appears to rest on these issues:

1. Can injected botulinum toxin migrate sufficiently, especially when used for spasticity, to cause paralysis of respiratory muscles?
2. Can injected botulinum toxin cause seizures?
3. Did Allergan promote the off-label use of Botox for pediatric spasticity?

Related to the third issue is whether Allergan promoted the off-label use of Botox a) at particularly high doses and b) despite being aware of the related dangers.

For its part, Allergan is claiming that Botox did not cause the death of the 7-year-old girl, Kristen Spears, who received a series of 7 Botox treatments, beginning at the age of 6 years, for muscle spasticity in her legs, groin, and chest. Spears's mother alleges that these treatments led to the girl's clinical deterioration. Already underweight and with a baseline seizure disorder, Kristen allegedly experienced more severe seizures and swallowing difficulties after her treatments began. The latter problem, along with breathing problems, led to 10 hospitalizations. Kristen died of respiratory failure and pneumonia in November 2007, reports the LA Times. 

Apparently on the basis of Kristen's case and others, the FDA announced last year that it had received postmarketing reports of toxin spread, when the drug was used to treat spasticity in children or adults. The reported symptoms were essentially those of botulism: dysphagia and respiratory compromise. Consequently the agency required makers of botulinum toxin products to add a black-box warning to their drug labels, advising of the risk of toxin spread.

But in its very recent review of published trials, the American Academy of Neurology (AAN) did not find evidence of drug-associated hospitalization or death when botulinum toxin was used to treat limb spasticity in children. All trial-based adverse events—the most common being localized pain, excessive weakness, unsteadiness, increased falls, and fatigue—were transient. Dysphagia was observed in 2 patients among more than 500 children. Seizures or the increased severity of seizures were not reported.*

The plaintiffs also argue that Allergan, in violation of federal law, promoted the off-label use of Botox for pediatric spasticity and specifically in the case of Kristen Spears. The company allegedly paid for the girl's pediatrician, Rolf Habersang, and his nurse practitioner wife to attend sponsored training seminars in 2000 and 2001 and arranged for Dr. Habersang to receive instruction from an Arkansas pediatric neurologist. In depositions, Habersang testified that he learned to use Botox at a dosage of 15 units/kg—a high, but not-unheard-of, dose in the case of CP-related spasticity in kids. The suit also alleges that Allergan sales reps discussed the off-label use of Botox repeatedly with the Habersangs and provided the dosage range of 10-15 units/kg for juvenile spasticity.

While the off-label promotion reportedly took place, the company knew of mounting Botox-related adverse events, the plaintiffs claim. Beginning in 2005, Allergan became aware of European reports of toxin spread that led to aspiration and death, and the company accumulated its own safety database, at least some of which it shared with the FDA. Also according to the plaintiffs, Allergan knew of reports of Botox-related seizures.*

The plaintiffs' allegations of off-label promotion, if true, are at complete odds with Allergan's current stance against the FDA, which requested last year that the company disseminate safety information about the off-label use of Botox. The agency's request led to Allergan's pending federal suit against the government, which seeks "declaratory relief" from the FDA's long-time restrictions against the discussion of off-label uses of prescription drugs.

To confuse matters even further, Allergan's supplemental biologics license application (sBLA) for the use of Botox in upper-limb spasticity after stroke is currently being considered by the FDA. The goal date for the agency's decision is April 1st.

Currently Botox is approved to treat spasticity associated with pediatric CP in more than 60 countries, according to news reports. In the United States, the drug's off-label use for CP-related spasticity is, by and large, considered standard practice.

* Because the effects of botulinum toxin are strictly confined to the neuromuscular junction, it seems highly unlikely that a direct mechanism exists for the drug to cause or exacerbate seizures. However, it is conceivable that the drug, through respiratory compromise, could indirectly precipitate or exacerbate seizures through hypoxic brain damage. The case of Kristen Spears, as reported, is unusual in that she received injections of botulinum toxin in her chest, which could have paralyzed her intercostal muscles.

02/01/10 addendum: The total doses used in the pediatric Botox studies that were assessed by the AAN ranged from 2 to no more than 13 U/kg for upper-extremity spasticity (n = 193; age range, 2.5-10 years) and from 4 to 30 U/kg for lower-extremity spasticity (n = 286; age range, 2-16 years). Ranges of respective per-muscle doses, when provided, were 0.3-4 U/kg and 4-6 U/kg (only 1 lower-extremity study provided these data).