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From: TSS ()
Subject: TSE ADVISORY COMMITTEE Documents posted on September 19, 2005
Date: September 27, 2005 at 2:47 pm PST

##################### Bovine Spongiform Encephalopathy #####################

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.

http://www.fda.gov/ohrms/dockets/ac/05/minutes/2005-4088M1_draft-quick-summary.pdf

TSS

#################### https://lists.aegee.org/bse-l.html ####################




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