The Transmissible Spongiform Encephalopathies Advisory Committee met Oct. 28-29 to discuss various issues related to the risk of potential exposure to variant Creutzfeldt-Jakob disease , or vCJD, and whether changes to the labeling of products — including plasma-derived albumin and products containing plasma-derived albumin — to address the possible risk of transmission of vCJD is warranted. The committee heard presentations related to the Food and Drug Administration’s geographic donor deferral policy to reduce the possible risk of transmission of CJD and vCJD by blood and blood products and human cells, tissue, and cellular and tissue-based products, and updates on the development of devices to remove transmissible spongiform encephalopathy agents from blood components.
FDA provided a historical review and an updated assessment of potential risk of transmission of vCJD through U.S.-licensed plasma-derived coagulation factor VIII. Inputs to the risk model were reviewed, and the committee was in unanimous agreement with the FDA conclusion that the risk of vCJD to patients who receive U.S.-licensed plasma-derived coagulation factor VIII products is likely to be extremely small, although the risk is not known with certainty. Following the 2009 report in the U.K. of vCJD infection transmitted by plasma-derived factor VIII (death from unrelated causes), the FDA and industry have looked again at the labeling on plasma derivatives (with and without albumin) and considered the extremely remote likelihood of transmission based on 1) no epidemiological evidence in the U.K. or U.S. for transmission by albumin-containing products; and 2) TSE clearance by precipitation processes for albumin exceeding that of other plasma protein fractions. Currently, the labeling mentions remote risk of viral infections and theoretical transmission of CJD, but there is no mention of vCJD. FDA proposed wording that would include remote risk of vCJD, and the committee was in unanimous agreement that a change to the labeling was appropriate. This would be similar to the language used for whole blood and blood components.
The committee was reminded of FDA’s policies that affect the eligibility of blood and HCT/P donors, including risk associated with travel to specific geographical areas, blood transfusions that may have occurred in these locations and, for a very small population, use of U.K.-sourced bovine insulin. FDA did not ask the committee to consider any changes to the policies. However, during the public hearing, Dr. Marc Germain, on behalf of the American Association of Tissue Banks, did present several points of view that were of particular significance to the tissue community and suggested that it was time — now 10 years later — to revisit the policies in light of the fact that there has been no documented transmission through tissue use and a lack of evidence that the geographical deferrals have prevented transmission. Dr. Celso Bianco, serving as the non-voting industry representative on the committee, also asked FDA to reconsider the risk assessment as it relates to donors — particularly the proportional application of the precautionary principle as it applies to the tissue donor population.
In addition to donor deferral policies and a desire to have a vCJD donor screening test, FDA has established criteria and possible label claims for devices to remove TSE infectivity from blood components. The committee previously has advised FDA on the validation criteria for the devices, and they were updated on recent advances by three manufacturers — Asahi-Kasei Medical, Pall Medical Corporation and Prometric BioSciences.