Pneumonia deaths seen with Glaxo vaccine: FDA

WASHINGTON (Reuters) - GlaxoSmithKline Plc's rotavirus vaccine is effective but also associated with an increase in pneumonia-related deaths and other reactions, U.S. regulatory staff said in documents posted on Friday.

The review comes ahead of a U.S. Food and Drug Administration advisory meeting on Wednesday to consider approval of the oral vaccine, which aims to prevent rotavirus infection, a cause of severe infant diarrhea that requires hospitalization.

The virus is a major killer of children in developing countries, but deaths in the United States are rare.

FDA staff said its analysis of 11 studies revealed that in the largest trial, there was a statistically significant increase in deaths related to pneumonia compared with placebos, documents posted on the FDA's Web site said.

Bernstein Research analyst Tim Anderson said safety issues could mar his forecasts for the drug reaching sales of $1.3 billion by 2012.

The drug could compete with Merck & Co's RotaTeq vaccine, and a negative safety label for Glaxo could give Merck an advantage, he said.

The two "are battling it out in the area of pediatric rotavirus vaccines," Anderson said.

Deutsche Bank analyst Brian Bourdot downplayed the FDA report, noting the European Medicines Agency has already considered some of the same safety issues with Rotarix, which is already approved outside the United States.

Merck's vaccine is sold in both the United States and abroad. Anderson said Glaxo's two-dose regime, compared with Merck's three-dose course, could give it an advantage depending on how the safety data are interpreted.

The issues with Rotarix come on the heels of problems with Glaxo's blockbuster Cervarix vaccine, a rival to Merck's cervical cancer prevention shot Gardasil. Approval of Cervarix was delayed by the FDA in December and Glaxo says it aims to respond to the agency's concerns during the second quarter of this year.

LARGEST STUDY

In a conclusion section, the FDA documents said the drug was effective at preventing rotavirus-related gastroenteritis, but also noted the pneumonia-related deaths and convulsions. It did not appear to make a recommendation to the advisory panel.

That expert panel will weigh the staff review, but makes its own recommendation, which is typically followed by the

FDA.

The rate of pneumonia-related death was 0.051 percent with the Glaxo vaccine, versus 0.019 percent with a placebo, a difference that statistically was not likely due to chance.

The biggest study, which enrolled about 63,000 children, also found an increase in convulsions in children given the drug, named Rotarix. Another study found an increased rate of bronchitis, compared with placebos.

Rotarix was found not to be linked with a bowel condition called intussusception that caused an earlier rotavirus drug sold by Wyeth to be pulled off the market, FDA staff said.

Glaxo, in documents prepared for the FDA meeting, noted that respiratory infections like pneumonia account for "dramatically greater numbers and proportions of infant deaths in Latin America, compared to the U.S."

The study took place primarily in Latin America.

Last year, the label for Merck's vaccine was changed to include reports of Kawasaki disease, a serious but uncommon illness that causes fever and blood-vessel inflammation.

The FDA staff summary said there were 27 cases of Kawasaki disease reported with Glaxo's vaccine, with 3 cases occurring within 30 days of vaccination.

(Reporting by Kim Dixon; Editing by Brian Moss and Steve Orlofsky, Richard Chang)