1. Chairman outlined the morning's program and stressed the shortage of time. At present there is one document with the SSC seeking a final approval for publication (In vivo recovery of factor VIII following transfusion, Dr. Christopher Prowse).

2. STANDARDIZATION
a) Concentrate standards. Dr. Barrowcliffe announced that the 5th International Standard for Factor VIII concentrate was approved by the WHO, with a potency of 5.4 IU/ml. The 3rd International Standard for Factor II-IX-X concentrate had been assessed with consistency. He discussed the possibility of a common monocomponent factor IX concentrate. Dr. Weinstein reported on the progress of work on the FDA/EP common standard which should be complete by the end of 1995. Regarding a factor IXa standard, Dr. Gray discussed variations associated with different methodologies.
b)Plasma standards. Dr. Barrowcliffe has produced a new Factor II-VII-IX-X plasma standard that will be calibrated this autumn. With regard to the 3rd International Standard for Plasma Factor VIII/ von Willebrand Factor, several large plasma pools have now assayed above 100% for factor VIII. He prompted investigators to send him results from their own laboratories. Dr. Kitchen described progress in assessing the SSC secondary plasma standard. These studies are soon to be completed, with stability testing and a few results to be included.
c) Dr. Barrowcliffe described the Factor VIII and IX Concentrate Field Study involving mainly commercial laboratories. The variation seen was related to use of different assay methods, and analytical approaches. It was noted that the chromogenic assay showed a large variation which was discussed. Further studies will be overseen by a small steering group chaired by Dr. Christopher Prowse.
d) Dr. Lee reported that she had found apparent different recoveries of factor VIII in the same patients with the same infusion by one-stage or chromogenic assay.

3. LABELING AND PURITY OF FACTOR VIII CONCENTRATES
Dr. Tuddenham spoke to his paper on this issue which was followed by vigorous discussion. It was the feeling of the meeting that the Subcommittee should recommend that the use of non-scientific purity descriptive phrases should be discouraged in papers and the commercial literature. It should be recommended that products are described in terms of their final constituents and their production technology. The Chairman requested that interested parties write to him so that the final recommendations will be acceptable.

4. A STUDY TO MONITOR THE VIRAL SAFETY OF PCR SCREENED BLOOD PRODUCTS IN NON-INFECTED PATIENTS (NIPS)
Dr. Berntorp proposed a new approach for safety assessment of viral transmission by blood products using NIPS in which PCR analysis would be used to monitor infection. It was decided to include this in proposed guidelines for the surveillance of viral transmission in PUPS (see below).

5. THE GENETIC BASIS OF FACTOR VIII INHIBITORS
In the absence of Dr. Hoyer, the Chairman outlined proposals for the study of the genetic basis of inhibitor development in severe haemophilia A with factor VIII gene inversions. This should either be in PUPS or in existing patients where the inhibitor status was known. Along with this, patients HLA class I and II characteristics would be assessed. Dr. Hoyer had proposed a prospective study and in the light of the comments made during the meeting, the Chairman would discuss the proposal further with him. It was clear that problems relating to the numbers of patients and their differing ethnic origins would make these studies difficult.

6. PROGRESS REPORTS AND FINAL REPORTS
a) Dr. Hill (on behalf of himself, Dr. Mannucci and Dr. Ludlam) outlined their proposals for surveillance of viral transmission in PUPS. There was considerable discussion and, following this, the Chairman requested that all interested parties should write to him, or the authors. A draft document would then be circulated to Subcommittee members and others for comment.
b) The following final reports were made (chaired by Dr. Kasper)
Registry of European-derived clotting factor concentrates (Dr. Costa e Silva)
Registry of North American-derived clotting factor concentrates (Dr. Menache)
Registry of North American Immune Tolerance Practices (Dr. diMichelle)
International Registry of Immune Tolerance Studies (Dr. Mariani)
Protocols for surveillance of inhibitor development in PUPS (introduced by Dr. Kasper, expanded by Dr. Klose)

The Chairman requested that these reports be sent to him as soon as available for assessment by the Subcommittee members prior to final submission to the SSC with a view to publication.

7. NEW PROPOSALS
a) Dr. E. Briet discussed the need to monitor inhibitor development in previously treated patients exposed to a new concentrate. Although that it was felt that such practices are being conducted in many centers, it was thought that this could be included in the inhibitor surveillance guidelines proposed by the Subcommittee. Dr. Bri?t agreed to write to the Chairman outlining his proposal.
b) Dr. Verbruggen described a minor change in the Bethesda inhibitor assay to stabilize factor VIII in the control sample which resulted in a more sensitive and parallel assay. The possibility of a collaborative study was discussed.
c) Dr. J. Lusher proposed a worldwide pharmacokinetic study of factor VIII and IX in infants below the age of five with severe haemophilia. She asked interested doctors to contact either her or Dr. Laurian .

8. CONCLUSION
The Chairman thanked all participants and presenters and said that details of all projects would be sent to the Subcommittee members shortly. The arrangements for 1996 Meeting have yet to be finalized.