Introduction/background: Development of neutralizing inhibitors against factor VIII (FVIII) is a major complication of haemophilia A treatment.Aim: The ongoing, international, open‐label, uncontrolled, observational immune tolerance induction (ObsITI) study evaluates ITI, the standard of care in patients with inhibitors.Patients/methods: Forty‐eight prospective patients in this interim analysis received a single plasma‐derived, von Willebrand factor‐stabilized, FVIII concentrate (pdFVIII/VWF) for ITI. According to recommended Bonn protocol, ‘low responders’ at ITI start (<5 BU) received 50–100 IU FVIII kg⁻¹ daily, or every other day; ‘high responders’ (≥5 BU) received 100 IU FVIII kg⁻¹ every 12 h.Results: Forty of 48 patients (83.3%), had at least one risk factor for poor ITI‐prognosis at ITI start (i.e. age ≥7 years, >2 years since inhibitor diagnosis, inhibitor titre ≥10 BU at the start of ITI, or prior ITI failure). Nonetheless, 34 patients (70.8%) achieved complete success, 3 (6.3%) partial success, 1 (2.1%) partial response; ITI failed in 10 patients (20.8%), all with poor prognosis factors. All six low responders achieved complete success. ITI outcome was significantly associated with inhibitor titre level at ITI start (P = 0.0068), number of poor prognosis factors for ITI success (P = 0.0187), monthly bleeding rate during ITI (P = 0.0005) and peak inhibitor titre during ITI (P = 0.0007). Twenty‐two of 35 high responder patients (62.9%) with ≥1 poor prognosis factor achieved complete success.Conclusion: Treatment with a single pdFVIII/VWF concentrate, mainly according to the Bonn protocol, resulted in a high ITI success rate in haemophilia A patients with inhibitors and poor prognosis for ITI success.

The British Journal of Haematology publishes original research papers in clinical, laboratory and experimental haematology. The Journal also features annotations, reviews, short reports, images in haematology and Letters to the Editor.

The next frontier in hemophilia A management has arrived. However, questions remain regarding the broader applicability of new and emerging hemophilia A therapies, such as the long-term safety and efficacy of non-factor therapies and optimal regimens for individual patients. With an ever-evolving clinical landscape, it is imperative for physicians to understand how available and future hemophilia A therapies could potentially be integrated into real-life clinical practice to improve patient outcomes. Against this background, nine hemophilia experts from Central European countries participated in a pre-advisory board meeting survey. The survey comprised 11 multiple-choice questions about current treatment practices and future factor and non-factor replacement therapies. The survey questions were developed to reflect current unmet needs in hemophilia management reflected in the literature. The experts also took part in a follow-up advisory board meeting to discuss the most important unmet needs for hemophilia management as well as the pre-meeting survey results. All experts highlighted the challenge of maintaining optimal trough levels with prophylaxis as their most pressing concern. Targeting trough levels of ≥30–50 IU/L or even higher to achieve less bleeding was highlighted as their preferred strategy. However, the experts had an equal opinion on how this could be achieved (i.e., more efficacious non-factor therapies or factor therapy offering broader personalization possibilities such as targeting trough levels to individual pharmacokinetic data). In summary, our study favors personalized prophylaxis to individual pharmacokinetic data rather than a "one-size-fits-all" approach to hemophilia A management to maintain optimal trough levels for individual patients.

Coagulation factor VII (proconvertin) is one of the proteins starting the blood coagulation cascade. Plasma FVII concentration is regulated by different factors. A low level of FVII could also be a result of FVII deficiency (MIM# 227500), the rare autosomal recessive inherited disease caused by pathogenic variants in the F7 gene. The aim of this study was to describe a mutation spectrum of the F7 gene and genotype–phenotype relationship in patients with FVII deficiency in Russia for the first time. We studied the primary structure of the F7 gene of 54 unrelated patients with FVII deficiency by direct Sanger sequencing. Pathogenic variants in the F7 gene were detected in 37 (68.5%) of them. We identified 24 different mutations located mostly in the serine protease domain. Five pathogenic variants had never been reported before. A major mutation in the Russian population was c.1391delC (p. Pro464Hisfs*32), linked with rs36209567 and rs6046 functional polymorphisms, that is widely distributed in East Europe. As in other countries, the F7 genotypes poorly correlated with the severity of clinical manifestations but were quite well associated with FVII levels. Minor alleles of functional polymorphisms rs510335, rs5742910, rs561241, rs36209567, and rs6046 could also participate in the F7 genotype and influence FVII levels.