Prion-busting filter to reach Europe in spring

The new product is designed to remove all the known prion types from donated blood stocks before they are delivered to the patient and could help alleviate shortages of blood components caused by the current ban on blood donations from people who lived in countries with bovine spongiform encephalopathy (BSE) infected cattle, who are at risk of contracting CJD from eating contaminated meat products.

There have been two probable cases of human-to-human vCJD transmission via blood transfusions reported in the past year. But because there are no clinical signs or symptoms of the disease for many years, and the only reliable tests to determine who has the disease are performed post-mortem, there is no way of knowing how many people may be harbouring the disease and donating blood.

Pall's Leukotrap Affinity Prion Reduction Filter removes infectious prions from red cells, the most widely transfused blood component, and is the latest in a range of products aimed at reducing unwanted components from blood sources.

Discussing the implications of the BSE-related ban on blood product stocks, Sam Coker, technical director of Pall Medical, said "a loss of one per cent of donors involves approximately 75,000 to 85,000 individuals in the first year, not to mention their future potential donations."​

Because prions are often found inside white blood cells (leukocytes) some countries are already using technologies to remove leukocytes to help decrease the risk of transmitting prions via blood transfusions."But this removes only about 42 per cent of prion infectivity of blood,"​ according to Coker.

The benefit of Pall's Leukotrap system is that it removes both leukocytes and free prions in the blood, reducing prion infectivity by more than 99 per cent, he said.

Coker presented the data yesterday at a US Food & Drug Administration (FDA) advisory panel meeting to discuss the risk of potential exposure to variant CJD from blood transfusions. He also reviewed a study where it was found that the new filter reduces the human form of vCJD prions from red cells below the limit of detection of the Western blot assay, the gold standard of prion detection. Crucially, the filter does not damage red cells thereby not impacting their efficacy, purity and therapeutic value.

The panel meeting coincides with heightened concerns about the possibility of a second wave of mad cow disease in humans of unknown magnitude globally, including North America where new cases of mad cow disease have just been identified​. Japan has also recently confirmed a vCJD case.

Pall expects to launch the new filter in Europe this spring, and will follow this with marketing applications to regulatory agencies in North America. The company is also working on applying the basic technology to a diagnostic device to aid in the detection of BSE in cattle before entering the food supply.

According to the most recent figures from IMS Health, the market for blood products in the top 13 world markets grew faster than any other category in the pharmaceutical sector in the 12 months to November 2004.

The category put in a 13 per cent rise year-on-year to reach $12.5bn (€9.8bn).