Rolf Ljung

Consensus perspectives on prophylactic therapy for haemophilia: summary statement

Summary.  Participants in an international conference on prophylactic therapy for severe haemophilia developed a consensus summary of the findings and conclusions of the conference. In the consensus, participants agreed upon revised definitions for primary and secondary prophylaxis and also made recommendations concerning the need for an international system of pharmacovigilance. Considerations on starting prophylaxis, monitoring outcomes, and individualizing treatment regimens were discussed. Several research questions were identified as needing further investigation, including when to start and when to stop prophylaxis, optimal dosing and dose interval, and methods for assessment of long‐term treatment effects. Such studies should include carefully defined cohorts, validated orthopaedic and quality‐of‐life assessment instruments, and cost‐benefit analyses.

Factor VIII Products and Inhibitor Development in Severe Hemophilia A

BACKGROUND For previously untreated children with severe hemophilia A, it is unclear whether the type of factor VIII product administered and switching among products are associated with the development of clinically relevant inhibitory antibodies (inhibitor development). METHODS We evaluated 574 consecutive patients with severe hemophilia A (factor VIII activity, <0.01 IU per milliliter) who were born between 2000 and 2010 and collected data on all clotting-factor administration for up to 75 exposure days. The primary outcome was inhibitor development, which was defined as at least two positive inhibitor tests with decreased in vivo recovery of factor VIII levels. RESULTS Inhibitory antibodies developed in 177 of the 574 children (cumulative incidence, 32.4%); 116 patients had a high-titer inhibitory antibody, defined as a peak titer of at least 5 Bethesda units per milliliter (cumulative incidence, 22.4%). Plasma-derived products conferred a risk of inhibitor development that was similar to the risk with recombinant products (adjusted hazard ratio as compared with recombinant products, 0.96; 95% confidence interval [CI], 0.62 to 1.49). As compared with third-generation full-length recombinant products (derived from the full-length complementary DNA sequence of human factor VIII), second-generation full-length products were associated with an increased risk of inhibitor development (adjusted hazard ratio, 1.60; 95% CI, 1.08 to 2.37). The content of von Willebrand factor in the products and switching among products were not associated with the risk of inhibitor development. CONCLUSIONS Recombinant and plasma-derived factor VIII products conferred similar risks of inhibitor development, and the content of von Willebrand factor in the products and switching among products were not associated with the risk of inhibitor development. Second-generation full-length recombinant products were associated with an increased risk, as compared with third-generation products. (Funded by Bayer Healthcare and Baxter BioScience.).

Primary prophylaxis in severe haemophilia should be started at an early age but can be individualized

The frequency of joint bleeds and orthopaedic joint scores were evaluated in 121 patients with severe haemophilia who had started prophylactic treatment with clotting factor concentrates at least once weekly before the age of 10. 75 of the patients started before the age of 3, 31 at the age of 3–5 and 15 at the age of 6–9. Each subgroup was evaluated separately. In addition, a regimen of one infusion weekly was compared with that of two (haemophilia B) or three (haemophilia A) infusions weekly in each patient.

Factor IX inhibitors and anaphylaxis in hemophilia B

PURPOSE We present clinical and laboratory data on 18 children from 12 hemophilia treatment centers in the United States, Canada, and Europe with the purpose of disseminating information regarding a recently recognized, potentially life-threatening complication of treatment in very young children with hemophilia B. PATIENTS AND METHODS Twelve hemophilia centers from the United States, Canada, and Europe provided clinical information and laboratory data concerning 18 children who had severe allergic reactions to infused factor (F) IX in close association with the development of an inhibitor to FIX. Laboratory testing for establishment of the diagnosis of hemophilia B and inhibitor to FIX was done locally at the centers treating these patients. FIX gene analysis was performed at one of six molecular genetics institutes. RESULTS All 18 children had severe hemophilia B, and in each an inhibitor antibody to FIX developed. The median age at the time of anaphylaxis (or anaphylactoid reaction) was 16 months, and the median number of exposure days to FIX was 11. The FIX inhibitor was detected almost simultaneously with the first occurrence of anaphylaxis in 12 of 18 patients. Maximum inhibitor titers were 4.5-600 Bethesda units (BU), with a median titer of 48 BU. FIX gene analysis, performed in 17 of 18 patients, demonstrated complete deletion of the FIX gene in 10 and major derangements in seven. Immune tolerance induction (ITI) regimens have been attempted in 12 patients, with generally poor responses. Two of the 12 experienced nephrotic syndrome while on ITI. Recombinant FVIIa has been successfully used to treat bleeding episodes in 11 of these children. CONCLUSION Physicians treating young children with hemophilia B should be aware of the potentially life-threatening complication of anaphylaxis. Children with complete gene deletions or major derangements of the FIX gene appear to be at greater risk. Those identified by genotype as being at greater risk may need to receive their first 10-20 treatments in a medical facility equipped for handling such emergencies. Recombinant FVIIa, although not licensed for use in the United States, appears to be the most suitable treatment option for bleeding episodes in such patients.

Intensity of factor VIII treatment and inhibitor development in children with severe hemophilia A: the RODIN study

The objective of this study was to examine the association of the intensity of treatment, ranging from high-dose intensive factor VIII (FVIII) treatment to prophylactic treatment, with the inhibitor incidence among previously untreated patients with severe hemophilia A. This cohort study aimed to include consecutive patients with a FVIII activity < 0.01 IU/mL, born between 2000 and 2010, and observed during their first 75 FVIII exposure days. Intensive FVIII treatment of hemorrhages or surgery at the start of treatment was associated with an increased inhibitor risk (adjusted hazard ratio [aHR], 2.0; 95% confidence interval [CI], 1.3-3.0). High-dose FVIII treatment was associated with a higher inhibitor risk than low-dose FVIII treatment (aHR, 2.3; 95% CI, 1.0-4.8). Prophylaxis was only associated with a decreased overall inhibitor incidence after 20 exposure days of FVIII. The association with prophylaxis was more pronounced in patients with low-risk F8 genotypes than in patients with high-risk F8 genotypes (aHR, 0.61, 95% CI, 0.19-2.0 and aHR, 0.85, 95% CI, 0.51-1.4, respectively). In conclusion, our findings suggest that in previously untreated patients with severe hemophilia A, high-dosed intensive FVIII treatment increases inhibitor risk and prophylactic FVIII treatment decreases inhibitor risk, especially in patients with low-risk F8 mutations.

Definitions in hemophilia: communication from the SSC of the ISTH

V. S . BLANCHETTE ,* N . S . KEY ,† L . R . L JUNG,‡ M. J . MANCOJOHNSON,§ H. M. VAN DEN BERG ¶ and A . SR IVASTAVA,** FOR THE SUBCOMMITTEE ON FACTOR VI I I , FACTOR IX AND RARE COAGULAT ION DISORDERS *Pediatric Thrombosis and Hemostasis Program, The Hospital for Sick Children, Department of Pediatrics, University of Toronto, ON, Canada; †Departments of Medicine and Pathology, UNC Hemophilia and Thrombosis Center Chapel Hill, Hill, NC, USA; ‡Department of Paediatrics and Malmo Centre for Thrombosis and Haemostasis, Lund University, Skanes Universitetssjukhus, Malmo, Sweden; §Hemophilia and Thrombosis Center, University of Colorado School of Medicine, Aurora, CO, USA; ¶Julius Center for Health Sciences and Primary Care, UMC Utrecht, Utrecht, the Netherlands; and **Department of Hematology, Christian Medical College, Vellore, India

Prophylactic treatment for severe haemophilia: comparison of an intermediate‐dose to a high‐dose regimen

Summary.  A multicentre study was performed in Sweden and the Netherlands, comparing effects of two prophylactic regimens in 128 patients with severe haemophilia, born 1970–90. 42 Swedish patients (high‐dose prophylaxis), were compared with 86 Dutch patients (intermediate‐dose prophylaxis). Patients were evaluated at the date of their last radiological score according to Pettersson. Annual clotting factor consumption and bleeding frequency were registered for a period of three years before evaluation. Patients in the high‐dose group were younger at evaluation (median 15.2 vs. 17.9 years), started prophylaxis earlier (median 2 vs. 5 years), and used 2.19 times more clotting factor kg−1 year−1. Patients treated with high‐dose prophylaxis had fewer joint bleeds (median 0.3 year−1 vs. 3.3 year−1) and the proportion of patients without arthropathy as measured by the Pettersson score was higher (69% vs. 32%), however, the age‐adjusted difference in scores (median 0 points vs. 4 points) was small and at present not statistically significant. Clinical scores and quality of life were similar. These findings suggest that, compared with intermediate‐dose prophylaxis, high‐dose prophylaxis significantly increases treatment costs and reduces joint bleeds over a period of 3 years, but only slightly reduces arthropathy after 17 years of follow‐up.

Intracranial haemorrhage in haemophilia A and B

In countries with a good standard of health care, intracranial haemorrhage (ICH) during the neonatal period affects 3·5–4·0% of all haemophilia boys, which is considerably (40–80 times) higher than expected in the normal population. ICHs are also frequent after the neonatal period, affecting 3–10% of the haemophilia population who are mainly treated on demand. The risk is higher in inhibitor patients. Spontaneous haemorrhage is reported more frequently than trauma‐induced haemorrhage in most studies. The prevalence of ICH in patients treated with a prophylactic regimen is not known. Although more frequent in younger patients, a substantial proportion of ICH occur in adults, suggesting that general risk factors because of age, such as hypertension, are increasingly important as the haemophiliac gets older. Some studies have reported a substantial proportion of ICH affecting patients with milder forms of haemophilia. The risk of ICH has to be considered when discussing treatment strategies for haemophilia patients.

Somatic Mosaicism in Hemophilia A: A Fairly Common Event

Mutations in the large gene of clotting factor VIII (FVIII) are the most common events leading to severe human bleeding disorder. The high proportion of de novo mutations observed in this gene raises the possibility that a significant proportion of such mutations does not derive from a single germ cell but instead should be attributed to a germline or somatic mosaic originating from a mutation during early embryogenesis. The present study explores this hypothesis by using allele-specific PCR to analyze 61 families that included members who had sporadic severe hemophilia A and known FVIII gene defects. The presence of somatic mosaicisms of varying degrees (0.2%-25%) could be shown in 8 (13%) of the 61 families and has been confirmed by a mutation-enrichment procedure. All mosaics were found in families with point mutations (8 [25%] of 32 families). In the subgroup of 8 families with CpG transitions, the percentage with mosaicism increased to 50% (4 of 8 families). In contrast, no mosaics were observed in 13 families with small deletions/insertions or in 16 families with intron 22 inversions. Our data suggest that mosaicism may represent a fairly common event in hemophilia A. As a consequence, risk assessment in genetic counseling should include consideration of the possibility of somatic mosaicism in families with apparently de novo mutations, especially families with the subtype of point mutations.

Intermediate-dose versus high-dose prophylaxis for severe hemophilia: comparing outcome and costs since the 1970s

Prophylactic treatment in severe hemophilia is very effective but is limited by cost issues. The implementation of 2 different prophylactic regimens in The Netherlands and Sweden since the 1970s may be considered a natural experiment. We compared the costs and outcomes of Dutch intermediate- and Swedish high-dose prophylactic regimens for patients with severe hemophilia (factor VIII/IX < 1 IU/dL) born between 1970 and 1994, using prospective standardized outcome assessment and retrospective collection of cost data. Seventy-eight Dutch and 50 Swedish patients, median age 24 years (range, 14-37 years), were included. Intermediate-dose prophylaxis used less factor concentrate (median: Netherlands, 2100 IU/kg per year [interquartile range (IQR), 1400-2900 IU/kg per year] vs Sweden, 4000 IU/kg per year [IQR, 3000-4900 IU/kg per year]); (P < .01). Clinical outcome was slightly inferior for the intermediate-dose regimen (P < .01) for 5-year bleeding (median, 1.3 [IQR, 0.8-2.7] vs 0 [IQR, 0.0-2.0] joint bleeds/y) and joint health (Haemophilia Joint Health Score >10 of 144 points in 46% vs 11% of participants), although social participation and quality of life were similar. Annual total costs were 66% higher for high-dose prophylaxis (mean, 180 [95% confidence interval, 163 - 196] × US