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May 17, 2010
 |  BioCentury  |  Regulation

Adventitious Detection

Rotarix, RotaTeq discoveries point to new framework for managing vaccine safety

Now that an academic researcher using new sequencing technology has detected foreign viral DNA in a live attenuated rotavirus vaccine, vaccine developers would be smart - and may eventually be required - to test all of their animal-derived vaccine materials with state-of-the-art technologies to ensure against contamination.

This testing will modestly slow down development and cost a bit more at the front end, and probably will reinforce efforts by vaccine companies to use non-animal derived materials.

At the same time, to prevent regulatory delays, excessive burden on agency staff and advisors, and revenue losses that could drive investment away from vaccine development, FDA will need to figure out how to routinely decide what to do when foreign material that has always been in a vaccine is detected with increasingly sensitive emerging technologies.

The agency must also determine how to communicate relevant information to the public.

If the rotavirus example proves to be representative of future cases of contamination, the extra time, cost and effort may yield little benefit to public health and safety. But in cases where less safety data has not yet accumulated, the possibility that vaccines could be found to harbor pathogenic viruses probably will drive new requirements for screening.

On March 22, FDA recommended a temporary suspension of the use of Rotarix live attenuated rotavirus vaccine from GlaxoSmithKline plc after porcine circovirus 1 (PCV1) was discovered in two batches of the vaccine.

The agency said follow-up testing showed the virus has been present in Rotarix since the early stages of development, including during clinical trials. FDA also said there is no known safety risk associated with the virus.

On a conference call that day, FDA Commissioner Margaret Hamburg said the decision to suspend use of the vaccine was based partly on the availability of an alternative rotavirus vaccine, RotaTeq from Merck & Co. Inc. Preliminary testing of RotaTeq did not detect components of PCV1.

"This was a difficult decision for us because there's no evidence at this time that there is a risk to patients who have received this vaccine, and we know there are real benefits for children to be vaccinated against rotavirus," Hamburg said on the call.

In contrast, the European Medicines Agency (EMA) and the World Health Organization (WHO) did not recommend any change to the way Rotarix is used in Europe and in the developing world.

FDA sought advice from its Vaccines and Related Biological Products Advisory Committee, which met on May 7 to discuss the use of Rotarix, as well as emerging technologies for detecting adventitious agents in vaccines.

The day before the meeting, FDA announced Merck had discovered fragments of DNA from PCV1 and PCV2 in RotaTeq. FDA did not recommend any change in use of that vaccine even though PCV2 is pathogenic in swine, while PCV1 is not.

Following discussion of the data, all but one of the panelists agreed the benefits of Rotarix and RotaTeq outweigh the risks of harm by the viral contaminants.

On Friday last week, the agency recommended that physicians resume the use of Rotarix and continue to use RotaTeq.

Poking around

The agency's reasoning provides a rough blueprint for making similar decisions in the future. FDA said the recommendation was based on the vaccines' strong safety records; no evidence that...

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