Research on prion removal technology presented to FDA Advisory Committee
East Hills, NY (Oct. 31, 2005) - - At the request of the Food and Drug Administration (FDA) Transmissible Spongiform Encephalopathies (TSEs) Advisory Committee, Pall Corporation (NYSE: PLL) today presented the latest research results on its prion technology to remove TSE infectivity from blood. The Pall LeukotrapR Affinity Prion Reduction Filter system is the only Council of Europe (CE) marked technology shown to remove prions from red blood cells, the most commonly transfused blood component. Samuel Coker. PhD, Principal Scientist and Technical Director of Pall Medical, who has been spearheading the research effort, gave the Committee a first-hand look at the validation studies on the performance characteristics of the prion reduction technology filter that were used to earn its CE mark in Europe. He also presented new results on quality control measures for blood banks to use upon implementation of prion reduction as a means to prevent transfusion-transmitted variant Creutzfeldt-Jakob Disease (vCJD).
TSEs, also called prion diseases, are fatal neurodegenerative diseases that include vCJD, the human form of bovine spongiform encephalopathy (BSE), or "mad cow disease." The presentation, part of the Advisory Committee's discussion on labeling claims for TSE clearance studies for blood component filters, is a continuation of Pall Corporation's dialogue with U.S. regulatory and health authorities on protecting the blood supply from prions that can cause vCJD.
Studies Validating Filter Performance
Dr. Coker presented research results on the ability of the filter to remove all types of prions from red cells including scrapie (a TSE affecting sheep); mouse infected with human variant CJD (mvCJD) and human sporadic CJD (sCJD). Sporadic CJD is the most common form of CJD affecting people.
He provided results of bioassays to provide a quantitative method to determine log removal of infectious prion in hamsters. (Hamsters are recognized as an optimal animal model for studying prion diseases.) These studies found that the technology was effective in reducing infectious prions in the human sCJD, scrapie and mvCJD models.
"These results demonstrate robust performance of the Leukotrap Affinity Prion Reduction Filter in removing different strains of prions," said Dr. Coker.
Dr. Coker reviewed results of studies on the safety of the product and details on the measurement of the quality of red cells post prion reduction, including survival, maintaining their integrity and therapeutic value (oxygen carrying properties) and other metabolic activities. On all counts measured, the studies found that the safety of processed red cells was not impaired.
Implementing Prion Reduction into Routine Blood Banking Practice
He also presented results of a new study that identified a surrogate marker to measure prion removal in order to enable quality control in the blood banking process. A surrogate marker is required since concentrations of infectious prion in blood are too low to measure using currently available methods. After review of a number of potential markers, the studies validated that reduction of a plasma protein present in blood and blood components directly correlated with reduction of infectious prion.
Dr. Coker explained, "These findings provide a feasible means for quality control for blood banks in their prion reduction process since the plasma protein can easily be measured with currently available analytical methods."
Studies on the efficacy of the filter's removal of prions under different processing conditions, which can vary by blood center and country in their use of anticoagulants, red cell storage solutions, temperatures, etc., were also reviewed. The studies showed about 99.9 percent prion removal across all conditions.
"The data show that the Leukotrap® Affinity Prion Reduction Filter is consistently effective in removing different strains of prions over a broad range of processing conditions," added Dr. Coker.
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
Published on PsychCentral.com. All rights reserved.
The best way out is always through.
-- Robert Frost