The European Medicines Agency (EMA) has released a draft Guideline on epidemiological data on blood transmissible infections intended to provide clarification on the data requirements for plasma-derived products.
In the EU, companies must submit scientific data for blood- or plasma-derived medicinal products using the plasma master file (PMF) certification procedure. The requirement for PMF certification was established in Directive 2003/63/EC, which replaced earlier requirements to include blood and plasma data in the product dossier.
Once certified, the PMF is incorporated into the companies' marketing authorization(s), and must be updated annually. Within the PMF, companies "are required to include the epidemiological data on the local viral epidemiology" for the collection centers used to gather the blood/plasma in the PMF.
EMA says this requirement is "an essential part of the measures taken to ensure an adequate selection of donors of blood and plasma," and contributes to the safety of products derived from blood components. Additionally, gathering epidemiological data allows health authorities to gauge infection risk and track trends in the epidemiological profile of certain regions and donor pools.
EMA says the new guideline was drafted following a public consultation in 2014 to reflect "additional experience acquired" from evaluations of epidemiological data over the previous four years.
The new revision is intended to give PMF holders additional guidance in several areas.
Currently, blood donors in the EU are screened for viruses that pose a high risk of transmission through blood products, including human immunodeficiency virus (HIV), hepatitis B virus (HBV) and hepatitis C virus (HCV). The guideline clarifies companies' responsibility to report confirmed results of these screenings, and they are instructed to report the positive results of other screenings, such as nucleic acid test assays separately. Additionally, companies must justify their criteria for excluding donors based on the results of these screenings.
In the EU, blood donors are classified as prospective, first time, repeat or regular donors. However, for epidemiological purposes, EMA has established two classifications of donors, "first time tested donor," and "repeat tested donor." EMA says these classifications are useful in tracking epidemiological and donor trends.
Epidemiology Data Reporting
EMA requests companies clearly describe the definitions of testing results and donor classification to facilitate comparability studies.
Organizations that collect both blood and plasma are instructed to collect data for the donor population for plasma, including the average number of donations per year and whether plasma donors are first time tested or repeat tested donors.
EMA says epidemiological data should be reported for the current year as well as the previous three years. Additionally, EMA requests data for whole blood recovered plasma and plasmapheresis be presented separately and asks that figures be recorded in absolute numbers per 100,000 donors.
Assessing the Data
The epidemiological data collected by PMF holders is important to understanding changes in the viral landscape over time. Tracking this data allows PMF holders to track "rates of infectious markers outside the normal range," which may be compared to the general population when the PMF is evaluated.
Companies should also establish criteria for so-called alert limits in situations when rates of specific viral markers are above a certain threshold. Companies should also have corrective measures in place for when an alert limit is triggered.
The draft guidance also provides instructions to companies for estimating the risk of viral infections going undetected during screening.
Because recently acquired infections may go undetected by some screening methods, EMA instructs companies to calculate the risk of infection in a "window period," for repeat tested donors. This is done by calculating the incidence of a particular infection in a donor pool and multiplying that figure by the window period, or "estimate of the time period in which a test method is unable to detect an infection."
For first time tested donors, EMA says companies can generally multiply the risk factor by three based on evidence in the scientific literature.
Additionally, the draft guideline also includes a model for adjusting the risk estimate for HBV infections. Due to the "transient nature of HBV infections," screenings may not be able to detect HBV infections acquired between donations.