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Notes: Summary.  The severe clotting defects associated with the diagnosis of severe haemophilia A and B require a quality management and quality assurance system designed to avoid both bleeding sequelae (such as damaged joints) through early on-demand or prophylactic treatment in a home-care setting, and side-effects such as infectious diseases (hepatitis A–G and human immunodeficiency virus), allergic reactions, haemolysis and if possible inhibitor formation, by using highly purified, virus-inactivated or recombinant products in which the factor VIII and IX proteins are as natural as possible. As the intravenous injection of the required clotting factor is entrusted to the patients in home treatment, the haemophilia centre has to check treatment protocols and, when necessary, joint and muscle status. In addition, it is imperative to ensure the safety of the product, and checks must be carried out to make sure that batch numbers are recalled as soon as possible if side-effects are observed. These are the reasons for several Acts of Parliament in Germany requiring special treatments and regular checks (the Disabled Act, recommendations by the German Medical Council, the Transfusion Act). Thus, at the haemophilia centre in Bonn we have established a special quality management and quality assurance system taking into account the great number of patients (〉 800), the often considerable distance between the centre and the patient, and the aforementioned regulations and laws. Quality management involves dealing with daily practicalities such as 24-h availability of a physician, medical technologist and nurse, careful instruction of patient and family in home care, genetic counselling, regular laboratory tests (especially recovery time, half-life, inhibitors and gene defects, clinical chemistry and serology) and clinical investigations (especially joint and muscle status). It also includes co-operation with family doctors and different departments at our university hospital (e.g. orthopaedic, microbiology), daily conferences with staff, information for nursery schools, schools, training institutions and/or the workplace in case of emergency, and cooperation with German haemophilia foundations. For quality assurance, several self-controlling systems are in place, such as distribution of concentrate, laboratory data, treatment protocols, joint and muscle status and bleeding tendencies. All these and more are double-checked and interactive, controlling data and activities with the help of EDP. Exceptional staff motivation and patient compliance are important for this quality system.

Notes: An immunoaffinity purified, solvent/detergent virally inactivated factor VIII (FVIII) concentrate (Hemofil® M) has been in clinical use in persons with haemophilia A since March 1987 and under clinical trial prior to licencing in the USA, Europe and Japan.The specification set and consistently met for the monoclonal antibody (mAb) content of the final product is 0.1 ng/IU FVIII. This level was considered non-immunogenic, based upon animal studies, recommendations of the European PHarmacopoeia with ovalbumin contamination of influenza vaccine and also the experience during clinical research studies using aAb for diagnostic or other clinical purpose as reported in the medical literature.This research communication documents the surveillance for human anti-murine antibodies (HAMA) in 13 patients with serve haemophilia A. These patients have been treated with a large amount of product (mean 14,026 IU), numerous different lots of Hemofil M (total 45; mean 17) over a substantial period of time (mean 28 months).The data generated from this group of 13 patients before and during therapeutic Hemofil M administration failed to show the development of any HAMA response at any timepoint. Therefore Hemofil M prepared by mAb resin immunoaffinity column chromatography under the currently set specifications for mAb contaminant of 0.1 ng/IU FVIII or less is a safe therapeutic agent in the management and prevention of bleeding episodes in persons with haemophilia A.

Notes: Summary.  Alloantibodies (inhibitors) against factor VIII (FVIII) develop in 20–30% of patients with severe haemophilia A and render classical FVIII substitution therapy ineffective. Several studies have shown that genetic factors, the type of FVIII gene mutation and immune response genes (e.g. the Major Histocompatibility Complexes), influence the risk of inhibitor formation. In particular, the type of FVIII gene mutation has proven to be a decisive risk factor. Patients with severe molecular gene defects (e.g. large deletions, nonsense mutations, intron-22 inversion) and no endogenous FVIII synthesis have a 7–10 times higher inhibitor prevalence than patients with milder molecular gene defects (e.g. missense mutations, small deletions, splice site mutations). To date, at least 10 distinct classes of mutations have been shown which have differing risks of associated inhibitor formation. A challenging observation in inhibitor patients is the heterogeneity of the antibody epitopes with respect to their number and their specifity. At least five epitopes in the FVIII molecule have been identified that constitute the targets for antibodies in most inhibitor patients. These epitopes are located in the ar3 region and the A2, A3, C1, C2 domains which correspond to the functional binding sites of the ligands of the FVIII protein. At present, the determinants of the characteristics of these epitopes and the subsequent inhibitor titre are unknown. A relationship of the mutation site and the epitope localization has been shown for some individual patients with mild haemophilia A. However, in severely affected haemophilia A patients, the influence of patient genetics on inhibitor titre and epitope specifity has yet to be elucidated.

Notes: Summary.  Technologies in molecular biology have greatly advanced the knowledge regarding the origin of haemophilia A and the physiology of the factor VIII (FVIII) protein. A variety of different mutations in the FVIII gene have been identified and their effects on the FVIII protein described. It has been shown that the frequency of haemophilia A is due to a high mutation rate predominantly in male germ cells. A significant proportion is originating de novo in early embryogenesis from somatic mutations, a finding that has implications for genetic counselling. The life-cycle of the FVIII protein and its structure-function relationships are continuously clarified. Most recently it has been shown that FVIII clearance from the circulation is mediated by the low-density lipoprotein receptor-related protein (LRP) and cell-surface heparan sulphate proteoglycans (HSPGs). These findings raise hope for novel recombinant FVIII molecules with prolonged half-life that may improve therapies for haemophlia A.

Notes: Summary.  Development of inhibitors to coagulation factors is one of the major problems faced by people with haemophilia. Up to a third of patients, following treatment with factor concentrates, will develop an antibody (inhibitor) to that factor, rendering it inactive, and leaving the patient at risk from life-threatening bleeding. Evidence shows that this immune response is T-cell-dependent, but as yet, the epitopes responsible have not been identified. Risk for inhibitor development is highest within the first 50 days of treatment, with reactions being rare after 200 days. The risk is mediated by the major histocompatibility complex class of the patient, and by mutations in the factor VIII genotype, with large deletions conferring greatest risk.

Notes: Treatment of previously untreated patients (PUPs) and minimally treated patients (MTPs) with severe hemophilia A using FVIII concentrates is complicated by FVIII inhibitor formation in ∼30% of patients. The incidence of FVIII inhibitors was determined in a prospective clinical trial of sucrose-formulated full-length recombinant FVIII (rFVIII-FS, KOGENATE® Bayer; Kogenate® FS) in pediatric patients.Methods:  PUPs and MTPs (=4 exposure days-EDs) with hemophilia A (〈2% FVIII) were enrolled from 19 EU and 13 US centers. Sixty patients were evaluable for inhibitor formation (EU, 31; US, 29). Patients were tested regularly with the Nijmegen-modified Bethesda assay (negative, ≤0.6 BU; Low Titer, 〉0.6-5 BU; High Titer, 〉5 BU).Results:  In the EU cohort (31 Caucasian), 4 patients developed inhibitors (3 Low; 1 High). Five high titer inhibitors developed in the US cohort (17 Caucasian; 5 Black; 7 Other). Median EDs at inhibitor detection was 8 [range, 3-16], and at study end 1 EU and 4 US patients had 〈20 EDs. The incidence of inhibitors in patients achieving 20 ED was 16.4% (9/55).Conclusions:  The rate of inhibitor formation in pediatric patients with severe hemophilia A treated with rFVIII-FS is consistent with that observed with plasma-derived and other recombinant FVIII products. Major gene disruptions were observed in all inhibitor patients.

Notes: Summary The incidence of male-to-female transmission of HIV infection was studied in a population of 198 sexual partners of hemophiliacs who tested HIV positive since 1984. The follow-up observation period was 1987–1992. Transmission occurred in 20 (10%) cases. The analysis of risk factors for transmission was performed in a subgroup of 57 hemophiliacs with seronegative sexual partners as compared to eight transmitters. Transmitters showed a significantly more advanced immune depletion at enrollment as well as at the end of the observation period. Furthermore, transmitters had a more advanced disease at the end of the study (75% vs. 29% CDC IV; p〈0.01). Also virus cultures were more frequently positive in the transmitters than in the non-transmitters (71% vs. 42%). Regular sexual counseling was offered to all couples. After 1987, no new seroconversions were detected. However, two seroconversions in female partners of hemophiliacs outside the initial study population were observed. Both transmissions occurred during a period of severe clinical and immunological deterioration. This study shows that sexual partners of HIV-infected hemophiliacs with more advanced disease are at higher risk of infection with HIV. The frequency of male-to-female transmission of HIV in long-term monogamous sexual relationships practicing safer sex is low. Overall, disease awareness and counseling for safer sex seem to be effective in reducing transmission rates.