Two studies published in the journal Transfusion have assessed prion removal from plasma-derived proteins and transfused plasma. Pathogenic prions in blood or blood products can lead to transmission of variant Creutzfeldt-Jakob disease. However, risk mitigation measures have been in place since the 1990s.
The first study, led by Dr. Kang Cai, assessed the prion removal capacity of protein purification methods used in the manufacturing of plasma-derived proteins.
In an accompanying editorial, Dr. Peter Foster commented on the study. Here is Dr. Foster:
“The data are very encouraging. A high degree of prion removal was observed across a wide range of products, with in many instances, multiple process steps being shown to contribute to the overall removal.”
Dr. Cai and colleagues found that the precipitation, adsorption, chromatography, and filtration processes reduced prion infectivity of the plasma-derived proteins. However, there may be some limitations.
According to Dr. Foster, it may not be clear how much prion removal is necessary: “There are a number of patients in the United Kingdom who have been treated with plasma products prepared with plasma from donors who went on to develop variant CJD. This of course begs the question – what degree of prion removal is required to ensure safety?”
In a second study, researchers conducted a phase I clinical trial to compare recovery, safety, and tolerability of a prion-depleted plasma product, Octaplas LG, to its previous generation solvent-detergent product, Octaplas SD.
Here is Dr. Jilma, who led the trial:
“A prion affinity chromatography step has been implemented into the Octaplas manufacturing process for an effective removal of prion proteins to increase further the safety of Octaplas solvent detergent product. The new plasma, which benefits from this improved manufacturing process, is named Octaplas LG.”
The trial found that both plasma products were bioequivalent with respect to clotting factors. However, the new plasma resulted in significantly higher plasmin inhibitor concentrations in vivo due to its shortened solvent detergent treatment. We’ll be back on September 30th with another edition of Transfusion News. Until then, thanks for joining us.
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