* FDA weighing recommendations on Merck, Glaxo vaccines
* Panelists urge long-term study
By Lisa Richwine
GAITHERSBURG, Md., May 7 (Reuters) - Benefits from rotavirus vaccines made by GlaxoSmithKline Plc (GSK.L) and Merck & Co Inc (MRK.N) outweigh any risk from recently discovered contamination with a pig virus, members of a U.S. advisory panel said on Friday.
Pieces of DNA from porcine circovirus (PCV) have been detected in Glaxo’s Rotarix and Merck’s Rotateq. The U.S. Food and Drug Administration said there was no evidence the virus harms people.
Several members of a Food and Drug Administration advisory panel said the vaccines carried impressive benefits from preventing rotavirus, which can cause fatal diarrhea, and agreed there was no sign so far of illness in people from PCV.
Any risks “are at best theoretical,” said Dr. Melinda Wharton, a panelist and deputy director of the Center for Disease Control and Prevention’s National Center for Immunization and Respiratory Diseases.
“Based on where we are with current knowledge, to me the known benefits clearly outweigh the risks,” she said.
The panel did not take any votes on formal recommendations to the agency.
In March the FDA advised doctors to stop using Rotarix after PCV-1 was found in the vaccine. Merck then tested its vaccine and the FDA announced on Thursday the company found pieces of DNA from PCV-1 and a related virus, PCV-2.
The FDA said it wanted the advisory panel’s input before making new recommendations on either vaccine. The agency will issue its latest advice “in the very near future,” said Karen Midthun, acting head of the FDA unit that reviews vaccines. “We need to consider this very expeditiously,” she told reporters.
Both PCV1 and PCV2 are common in pigs but neither is known to cause illness in humans, the FDA said. PCV2 is believed to cause postweaning multisystemic wasting syndrome in young piglets, marked by diarrhea and an inability to gain weight.
Advisory panel members urged further study to check for any long-term effects from PCV. Some also said parents needed to be told about the PCV finding.
“The fact that it poses no risk in the short term is certainly comforting. I don’t think that necessarily says it’s risk-free in the long term,” said panelist Stephen Hughes, head of the HIV drug resistance program at the National Cancer Institute.
Some panelists said they wanted to know more about PCV2. The committee heard less about that type as Merck’s finding was so recent. The meeting was originally scheduled just to discuss the Glaxo vaccine.
PCV1 apparently has been in Glaxo’s vaccine since it was first developed, the company said. Testing found DNA from the virus in master cells used to make the product.
The material may have come from a pig-derived enzyme called trypsin used early in development, Glaxo officials said.
“All available data support this is a manufacturing quality issue and not a safety issue. PCV1 does not pose a risk for infants vaccinated with Rotarix,” said Dr. Barbara Howe, a Glaxo vice president.
Glaxo said it planned to develop a rotavirus vaccine free from PCV1 but the process would take time.
Merck was not scheduled to speak at the meeting, but the company said on Thursday the levels of DNA from PCV were low in Rotateq and there was no sign it was harmful to people.
Vaccines against rotavirus have a troubled history. Wyeth’s Rotashield was pulled off the market in 1999 after it was linked with a rare but deadly bowel obstruction.
Rotavirus kills more than 500,000 infants each year, mostly in low- and middle-income countries. In the United States, deaths from the virus are rare but it caused more than 50,000 U.S. hospitalizations annually before Merck’s vaccine won FDA approval in 2006.
The World Health Organization and the European Medicines Agency have not recommended any changes in rotavirus vaccine use in Europe or developing countries.
In 2009, sales of Merck’s vaccine totaled $522 million, including $468 million from the United States.
Most of Glaxo’s rotavirus vaccine sales occur outside the United States. Worldwide sales in 2009 were $440 million, including $118 million from the United States. Glaxo’s vaccine won U.S. approval in 2008. (Reporting by Lisa Richwine, editing by Gerald E. McCormick and Carol Bishopric)