GlaxoSmithKline's Rotavirus Vaccine Suspended for Pig Virus Contamination
On Monday, as the nation was fully focused on passage of the sweeping health care reform bill, the U.S. Food and Drug Administration issued a recommendation regarding a common vaccine given to children to prevent severe diarrhea. The FDA told doctors to temporarily suspend use of GlaxoSmithKline's (GSK) Rotarix vaccine for rotavirus immunization while the agency investigates an extraneous component found in the vaccine.
GlaxoSmithKline notified the FDA on March 15 that an independent U.S. academic research team found, through novel methods, that the vaccine contains DNA from porcine circovirus 1 (PCV1), that is, components of a virus common among pigs. The FDA said there is no evidence at this time that this finding poses a safety risk, adding that "PCV1 is not known to cause illness in humans or other animals."
EMA and WHO See No Need To Take Action
Unlike the FDA, the European Medicines Agency "concluded that no action was necessary at this point" because "the findings do not present a public health threat." Still, the EMA added, "It is nonetheless clear that viral DNA should not be present in the vaccine and that its source is unclear," and therefore requested GSK "to provide further information as a matter of urgency." Similarly, the World Health Organization did not recommend change of the use of the vaccine.
The FDA's commissioner Margaret Hamburg stressed the importance of vaccination, but said that Americans have the luxury of using another licensed vaccine -- Merck & Co.'s (MRK) RotaTeq, in which no components of PCV1 have been detected. RotaTeq, licensed in 2006, is more commonly used in the U.S. than Rotarix, the FDA said.
Virus Was Present in Clinical Trials of Vaccine
The FDA said that Rotarix, licensed in 2008, has been studied extensively, before and after approval, and found to have an excellent safety record. Further, tests by Glaxo found the viral components were present not just in the finished product but also in the viral seed from which the vaccine is made. This means the viral components have been present since the early stages of the vaccine's development, including during clinical studies. Despite all that, the FDA said it prefers to be overly cautious and recommended to stop the use of Rotarix until further investigation.
Rotarix and RotaTeq are given by mouth to young infants to prevent rotavirus disease, which can cause severe diarrhea and dehydration, and is estimated to be responsible for the deaths of more than 500,000 infants around the world each year. Before the introduction of a rotavirus vaccine, rotavirus resulted in more than 50,000 hospitalizations and several dozen deaths in the U.S. each year, the FDA said.
Unfortunately, despite the central role vaccines have played in lowering the presence of so many diseases, when it comes to the rotavirus vaccine, there have been previous unnerving incidents. Specifically, Wyeth's Rotashield vaccine, approved in 1998, was voluntarily withdrawn from the market after a year because studies linked it to intussusception, a rare but serious bowel condition. Studies have not found that either Rotarix or RotaTeq rotavirus vaccines cause intussusception.
No Evidence of Safety Risk
GlaxoSmithKline said it is working to replace the cell bank and virus seeds used as base production material. But in the meantime, it will continue to manufacture the vaccine in accordance with regulators.
"No safety issue has been identified by external agencies or GSK," said Thomas Breuer, Chief Medical Officer of GSK Biologicals, in a statement. "We are already working closely and discussing this finding with regulatory agencies around the world."
GSK added that 90,000 people participated worldwide in the vaccine's clinical trial. The more than 69 million doses of Rotarix vaccine distributed globally reflect the excellent safety profile, it added.
Worldwide Rotarix sales in 2009 grew 50% to £282 million, or about $423 million, with U.S. representing £76 million, or $114 million. Still, this is but 1% of GSK's turnover of $28.4 billion, or some $42 billion, in 2009.
The FDA said its vaccine advisory committee would meet within the next four to six weeks to review the issue, including whether intact virus, as opposed to DNA fragments, is present. It added that no medical follow-up is needed for patients who have been vaccinated with Rotarix, estimated at 1 million kids in the U.S.