Sunday, July 12, 2009

FDA Reevaluates Safety of Plasma-derived Biologic Products

June 16, 2009 — The US Food and Drug Administration (FDA) Transmissible Spongiform Encephalopathies Advisory Committee has decided that no changes to blood-monitoring practices are required at this time. The committee met Friday to evaluate the risk for variant Creutzfeldt-Jakob disease (vCJD) in plasma-derived factor VIII products used for blood-clotting disorders.
Concern for patients was first sparked by a February announcement by health authorities in the United Kingdom reporting a vCJD infection in a person with hemophilia treated with a plasma product.
The FDA is now reevaluating whether current blood-donor policies are sufficient to maintain the safety of plasma-derived biologic products. The decision is anticipated to have international implications, because an estimated 50% of the world's plasma supply is provided by the United States.
Jay Epstein, director of the FDA's office of blood research and review, asked the committee if the UK announcement has "changed the landscape in a fundamental way" and should prompt changes in the United States.
The advisory committee voted unanimously that no changes are required at this time. The 15 voting members concluded that the risk for vCJD to patients who receive US-licensed plasma-derived coagulation factor VIII products is likely to be extremely small.
Committee chair Nick Hogan, MD, from the University of Texas Southwestern Medical School, in Dallas, said, "There is very little change to the modeling and epidemiological data, so there is very little reason to change this."
But during the open public hearing, some voiced concerns about the difficulty of reporting vCJD in many parts of the United States. Without thorough reporting, they question the accuracy of current data.

More Data Needed

The fatal neurodegenerative disease is acquired through infection with the agent that causes bovine spongiform encephalopathy. vCJD is typically acquired by consuming beef products from infected cattle. The first human cases of vCJD were reported in the United Kingdom in 1996. By May 2009, 211 definite or probable clinical cases of vCJD had been reported worldwide, with 168 of these in the United Kingdom.
At the open public hearing, some also raised concerns about inadequate animal surveillance. While countries such as Japan reportedly test every cow, this does not happen in many places, including the United States.
International health authorities have also been concerned about the risk for a secondary epidemic through human-to-human transmission. In the case that prompted the announcement in the United Kingdom, a 70 year-old man had been treated 11 years earlier with a plasma-derived factor VIII product. The product was reportedly developed from pooled plasma containing at least 1 donation from a person who later died of vCJD.
Postmortem examination of the 70-year-old's brain identified no neuropathological changes suggestive of Creutzfeldt-Jakob; however, his spleen revealed abnormal accumulations of prion protein typical of the disease.

Risk Likely Small

Mark Skinner, president of the World Federation of Hemophilia, said that he agrees with the advisory committee's decision. "While the risk may not be zero, it certainly is very small," he said at the meeting.
He suggests that current donor-deferral measures appear to be effective, but a donor screening test could still be useful. Mr. Skinner recommended that product warning labels should be updated to include vCJD among risk factors.
The committee discussed donor-deferral measures and product labeling at length but did not vote on these issues.
The FDA is considering the input from the advisory committee and will issue a final decision after its review.

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