Dec 27, 2005 (CIDRAP News) – The US Food and Drug Administration (FDA) gave its blessing last week to the use of the antiviral drug oseltamivir (Tamiflu) to prevent influenza in children between the ages of 1 and 12.
The FDA had previously approved oseltamivir for treating (but not preventing) flu in that age-group and for both treating and preventing flu in adolescents and adults. Many countries are stockpiling the drug to prepare for a possible flu pandemic.
In announcing its move, the FDA cited a study of the spread of flu in households. The study involved more than 1,100 people, including 222 children aged 1 to 12 years.
When someone in the household came down with flu, other household members received either no treatment (unless they became ill) or oseltamivir once a day for 10 days. Three percent of those who received the drug contracted flu, versus 17% of those who received no preventive treatment, the FDA said.
"The benefit in children mirrored the benefit seen in older individuals in this and earlier studies," the agency said.
The indicated dosage for preventive use in children is 30 to 60 milligrams per day, depending on body weight, for 10 days, according to Roche Pharmaceuticals, manufacturer of oseltamivir, a Swiss-based company with US headquarters in Nutley, N.J. Preventive use should begin within 48 hours after exposure to the virus, the company said.
"The approval of Tamiflu in this indication enables doctors to have a safe and effective medicine at hand to help prevent young children from getting influenza," said William M. Burns, CEO of Roche's Pharma division, in a company news release. The company noted that children younger than 2 years are as likely as those over age 65 to be hospitalized if they get the flu.
In studies, side effects of the prophylactic use of oseltamivir were similar to the side effects of treatment, the FDA said. The most common side effects were nausea, vomiting, headache, and fatigue. Vomiting was more common with twice-daily dosing than with once-daily dosing.
"In the current study, children reported higher rates of vomiting than adults but this was observed to be dose-related," the FDA said. No new side effects were seen in the study, but the agency has asked Roche for more post-marketing data on the safety of the drug.
In November the FDA announced that a thorough review of post-marketing safety data on oseltamivir had revealed a few reports of severe rash and allergic-like skin reactions that might have been drug-related. As a result, the agency ordered that a new warning about the possibility of serious skin reactions be added to the drug label.
In the same safety review, the FDA also examined reports of 12 deaths in Japanese children who were taking oseltamivir and concluded that the deaths were unrelated to the drug. The agency determined that the deaths were part of a wave of flu-related encephalitis and encephalopathy cases in Japanese children that began before oseltamivir was approved.
Dec 22 FDA news release
Dec 22 Roche news release
Nov 18, 2005, CIDRAP News story "FDA panel: children's deaths unrelated to Tamiflu"