Large deletions and small insertions and deletions in the factor VIII gene predict unfavorable immune tolerance induction outcome in people with severe hemophilia A and high-responding inhibitors.

INTRODUCTION: Hemophilia A is an inherited bleeding disorder caused by pathogenic variants in the factor VIII gene (F8), which leads to factor VIII (FVIII) deficiency. Immune tolerance induction (ITI) is a therapeutic approach to eradicate alloantibodies (inhibitors) against exogenous FVIII in people with inherited hemophilia A. Few studies have evaluated the role of F8 variants on ITI outcome. MATERIAL AND METHODS: We included people with severe hemophilia A (FVIII ˂ 1 international units/dL) and high-responding inhibitors (≥ 5 Bethesda units/mL lifelong) who underwent a first course of ITI. Socio-demographic, clinical and laboratory data were collected. ITI outcomes were defined as total, partial successes, and failure. Detection of intron 1 and 22 inversions was performed by polymerase-chain reaction, followed by F8 sequencing. RESULTS: We included 168 people with inherited hemophilia A and high-responding inhibitors, median age 6 years at ITI start. Intron 22 inversion was the most prevalent variant (53.6 %), followed by nonsense (16.1 %), small insertion/deletion (11.3 %), and large deletion (10.7 %). In comparison with intron 22 inversion, the odds of ITI failure were 15.5 times higher (odds ratio [OR] 15.50; 95 % confidence interval [95 % CI] 4.59-71.30) and 4.25 times higher (95 % CI, 1.53-12.3) among carriers of F8 large deletions and small insertions and deletions, respectively. CONCLUSION: F8 large deletions and small insertions/deletions predicted ITI failure after a first course of ITI in patients with severe hemophilia A and high-responding inhibitors. This is the first study to show F8 large deletions and small insertions/deletions as predictors of ITI failure.

Extended half-life recombinant factor VIII treatment of hemophilia A in Brazil: an expert consensus statement

Introduction Treatment of hemophilia A in Brazil is offered to all patients at no cost. However, several unmet medical needs exist. Method In this study, we applied the Delphi method to discuss with seven hemophilia A specialists the challenges that patients and the health system face regarding hemophilia A treatment and opportunities for improvement. Results A consensus was obtained regarding the number of weekly infusions and patient adherence to treatment. The bleeding profile, unfavourable pharmacokinetics (PKs), low adherence and high daily activity were patient profiles that would benefit from using the extended half-life (EHL) recombinant factor VIII (rFVIII). The advantages of treatment with the EHL rFVIII were the lower number of infusions per week, which could increase patient adherence and decrease the risk of bleeds, due to a more constant plasma level, a lower value. Additionally, the EHL rFVIII could improve quality of life, especially in patients with high daily activity, such as adolescents and young adults. The panelists mentioned that EHL rFVIII, if available, could be offered first to the priority group (adolescents between 12 and 19 years old), followed by adults (20 to 64 years old) and elderly people (over 65 years old). Conclusion In summary, the EHL rFVIII offers the optimal prophylaxis by decreasing the dose frequency, increasing the treatment adherence and improving the QoL, without compromising safety and efficacy.

Extended half-life recombinant factor VIII treatment of hemophilia A in Brazil: an expert consensus statement.

INTRODUCTION: Treatment of hemophilia A in Brazil is offered to all patients at no cost. However, several unmet medical needs exist. METHOD: In this study, we applied the Delphi method to discuss with seven hemophilia A specialists the challenges that patients and the health system face regarding hemophilia A treatment and opportunities for improvement. RESULTS: A consensus was obtained regarding the number of weekly infusions and patient adherence to treatment. The bleeding profile, unfavourable pharmacokinetics (PKs), low adherence and high daily activity were patient profiles that would benefit from using the extended half-life (EHL) recombinant factor VIII (rFVIII). The advantages of treatment with the EHL rFVIII were the lower number of infusions per week, which could increase patient adherence and decrease the risk of bleeds, due to a more constant plasma level, a lower value. Additionally, the EHL rFVIII could improve quality of life, especially in patients with high daily activity, such as adolescents and young adults. The panelists mentioned that EHL rFVIII, if available, could be offered first to the priority group (adolescents between 12 and 19 years old), followed by adults (20 to 64 years old) and elderly people (over 65 years old). CONCLUSION: In summary, the EHL rFVIII offers the optimal prophylaxis by decreasing the dose frequency, increasing the treatment adherence and improving the QoL, without compromising safety and efficacy.