Draft QUICK SUMMARY
for the
Transmissible Spongiform
Encephalopathies Advisory Committee (TSEAC)
on February 8, 2005
This quick
summary provides an unofficial overview of the February 8, 2005 TSEAC meeting
until transcripts are available.
The Committee received an update on the USDA, BSE surveillance program in the United
States by Dr. Lisa Ferguson, APHIS, USDA
Topic # 1 - Possible vCJD Risk from Investigational Coagulation
Factor XI Manufactured before 1998 from Plasma of Donors Residing in the United
Kingdom
After listening to Dr. Mark
Weinstein, FDA, summarize the issues related to this topic, the Committee
listened to a presentation on “Risk Assessment – U.K. plasma
derivatives, risk
assessment methods and assumptions and U.K. actions based on risk assessment”
by Dr. Kate Soldan and Ms. Anna Molesworth, from the U.K. Healthy Protection
Agency. The Committee then listened to
a presentation entitled “Risk
assessment for U.K. Factor XI (FIX)” by Dr. Steven. Anderson, FDA and a
presentation on “Current public health recommendations on management of
surgical instruments used on patients with TSE or TSE risk” by Dr. Lynne
Sehulster, from Center for Disease Control and Prevention. During the open public hearing session the
Committee also listened to a presentation from Dr. Samuel O. Coker, of Pall Medical on the
effectiveness of new filter technology to remove prions.
The Committee was then asked to comment on the
FDA vCJD risk assessment for Factor XI manufactured from U.K. plasma, with
regard to the model as applied to FXI; and any additional information that is
needed to improve risk estimates for this FXI product.
The Committee stated that the risk assessment model was valid, and logically developed. Members agreed with Dr. Anderson, that there are abundant uncertainties and not everyone will agree with all the assumptions that went into the model. The model is a very good start, however, it will need refining in the future. There was strong agreement that more data are needed for better assessment. This need for more data and testing was restated several times throughout the meeting. Some members expressed concern about how the model would be applied and what the public would be told. There was agreement that the model would help to assess the probability of exposure to infectious agent, if not the actual risk that recipients have been infected, but that planning also had to address the significance of estimated exposure prior to notifying patients. It was recommended that we find out what the UK has been telling Factor XI recipients. Several members stated that the issues related to Factor XI did not suggest high levels of risk, and they did not want to cause any unnecessary alarm.
Topic # 2 – Developing Risk Assessment
Models for Potential Risk of Exposure to variant Creutzfeldt-Jakob Disease
(vCJD) Agent in other Plasma Products
The Committee listened to a
presentation entitled “Preliminary Risk Assessment –
U.S. Potential TSE clearance steps in U.S. products - FVIII, FIX, IGIV” by Dr.
Dorothy Scott, FDA and a presentation on “Risk Assessment Model for U.S. plasma
derivatives” by Dr. Steve Anderson, FDA.
FDA requested the Committee
to discuss and comment on the U.S. risk model per se, and any additional
information that is needed to improve risk estimates for the various plasma
derivative.
Again the members stated
that the risk assessment model was a good model that will need additional
refining as more information is collected.
Members of the Committee expressed concern that, since there was
variability in how U.S. manufacturers produced their products, different
products and different methods of production will have different risks that
need to be considered. Committee
members also recommended that other factors such as travel history of the
donors might appropriately be considered in future models. The short period of stay in the UK (one
month in 1989) by a Japanese traveler who later came down with vCJD was
discussed as an issue of concern, as a reminder that current deferral of blood donors
who were in the UK for total periods of three months or more (1980 through
1996), while reducing risk, does not guarantee that every infected donor has
been deferred.
Topic # 3 – Potential Deferral of Blood
and Plasma Donors for History of Transfusion in European Countries
The Committee listened to
presentations on “Epidemiology of vCJD in France and
risk assessments for blood and plasma derivatives” written by Dr. Jean-Philippe Brandel,
Neurologist, Epidemiosurveillance Network (who could not attend the meeting so
the talk was co-presented by Drs. Pedro Piccardo and Stephen Anderson, FDA) and a presentation on “Estimates of
blood-borne vCJD risk in the U.K. and other European populations” by Dr. Sheila
M. Bird, Medical Research Council Biostatistics Unit, Institute of Public
Health, Cambridge University, and a presentation on “Risks and benefits of
deferring donors transfused in France and other European countries: potential
impact on blood and plasma supplies” by Dr. Alan Williams, FDA. The Committee
also listened to presentations during the open public hearing session from the
following organizations, American Association of Blood Banks, America’s Blood Centers, and the New York Blood
Center. These organizations agreed that
deferral of individuals transfused in France would not significantly affect the
U.S. blood supply, however, additional restrictions will increase the
complexity of the donor questionnaire and might have some additional effect in
discouraging blood donors. One
organization recommended that, as the epidemics of BSE and vCJD decrease in
magnitude, an “exit strategy” to relax current vCJD blood safety policies
should be considered.
Committee members noted an
earlier decision in France to defer all transfusion recipients, but agreed that
any recommendation for the US should be based on the available scientific data
and not on the French policy decision per se.
The Committee then discussed
the following questions:
1. Based upon the
available scientific information, does the committee recommend deferral of
blood donors transfused since 1980?
a.
In France?
The
Committee voted: 12 yes (in favor of deferral), 3 no, 1 abstained. (The
industry representative’s (IR’s) position was not to recommend deferral.)
b.
In other countries of
Europe?
The
Committee voted: 0 yes, 15 no (against
deferral), 1 abstained. (The IR’s position was not to recommend deferral.)
2. Based upon the
available scientific information, does the committee recommend deferral of
Source Plasma donors transfused since 1980?
a. In
France?
The
Committee voted: 5 yes, 7 no, 4 abstained. (The IR’s position was not to
recommend deferral.)
b. In other
countries of Europe?
The Committee voted: 0 yes, 16 no, 0 abstained. (The
IR’s position was not to recommend deferral.)
Please refer to the committee transcripts for a
detailed account of the meeting.