MHRA Re-assesses Ban on UK Plasma for Immunoglobulins

Dawn O'Shea

April 26, 2021

The Medicines and Healthcare products Regulatory Agency (MHRA) says lifting the ban on the use of UK plasma for the manufacture of immunoglobulins would result in little or no risk of variant Creutzfeldt-Jakob disease (vCJD).

In 1999, in response to the emergence of the vCJD epidemic in the UK associated with the consumption of meat products from bovine spongiform encephalopathy (BSE)-affected cattle, the Government introduced a ban on the use of UK human blood plasma for the manufacture of all plasma-derived medicinal products. Since the introduction of the ban, plasma for the manufacture of such products used in the UK has had to be imported. The main source of plasma for these products at present is the USA.

In a new report, the MHRA said there is general agreement that it is time to consider whether the ban is still necessary given that the vCJD risk from plasma products appears to be significantly lower than when it was implemented.

However, experts recommend a cautious approach in relation to prions, given the remaining uncertainties around the disease, especially the significance of asymptomatic carriers.

The mathematical model developed by the Department of Health and Social Care to estimate the vCJD risk of blood components was modified to apply it to immunoglobulins taking account of data, including the donor plasma pool size, the batch size and the prion reduction factor.

The risk of vCJD infection and of clinical case was estimated for 17 normal immunoglobulins and six hyperimmune immunoglobulins. If using non-leuco-depleted plasma and depending on the products, the risk of infection expressed per million of single maximum doses ranged from 0.0007 to 324 and the risk of a clinical case ranged from 0.00005 to 24 for normal Igs. For hyperimmune Igs, the risk of infection ranged from 0.0000045 to 0.0009 and the risk of clinical infection ranged from 0.0000003 to 0.00007.

Leucodepletion decreased the risk of infection approximately five-fold, and the risk of clinical case decreased by a factor of 3.5.

The number of vCJD clinical cases expected to occur in the future is estimated to be fewer than one to two cases for most products assessed; for the others, it is of the same order of magnitude as the 15 clinical cases predicted for fresh frozen plasma transfusions over the next 50 years. This level of risk was already considered acceptable for fresh frozen plasma transfusion, and the risk reduction measures previously in place for fresh frozen plasma have been subsequently withdrawn.

Based on external consultation and mathematical modelling, the MHRA review concluded that the use of plasma from UK donors for the manufacture of human Ig products would expose the target patient population to “no or minimal additional risk of vCJD in the future.”

This article originally appeared on Univadis, part of the Medscape Professional Network.


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