Key Points• The inhibitor incidence in nonsevere hemophilia A patients with certain F8 mutations approaches the inhibitor incidence in severe patients.• These findings are highly relevant for clinical practice, as they facilitate identification of high-risk patients based on F8 genotype.Neutralizing antibodies (inhibitors) toward factor VIII form a severe complication in nonsevere hemophilia A, profoundly aggravating the bleeding pattern. Identification of high-risk patients is hampered by lack of data that take exposure days to therapeutic factor VIII concentrates into account. In the INSIGHT study, we analyzed the association between F8 mutation and inhibitor development in patients with nonsevere hemophilia A (factor VIII 2-40 IU/dL). This analysis included 1112 nonsevere hemophilia A patients from 14 centers in Europe and Australia that had genotyped at least 70% of their patients. Inhibitor risk was calculated as KaplanMeier incidence with cumulative number of exposure days as the time variable. During 44 800 exposure days (median, 24 exposure days per patient; interquartile range [IQR], 7-90), 59 of the 1112 patients developed an inhibitor; cumulative incidence of 5.3% (95% confidence interval [CI], 4.0-6.6) after a median of 28 exposure days (IQR,. The inhibitor risk at 50 exposure days was 6.7% (95% CI, 4.5-8.9) and at 100 exposure days the risk further increased to 13.3% (95% CI, 9.6-17.0). Among a total of 214 different F8 missense mutations 19 were associated with inhibitor development. These results emphasize the importance of F8 genotyping in nonsevere hemophilia A. (Blood. 2013; 122(11):1954-1962 IntroductionPatients with hemophilia A who are treated with factor VIII concentrates are at risk of developing factor VIII neutralizing alloantibodies (inhibitors).1,2 Inhibitor development is one of the most challenging complications in the treatment of hemophilia A, as it increases the bleeding tendency while it renders treatment with therapeutic factor VIII concentrates ineffective. Although inhibitor development is less frequently observed in patients with nonsevere hemophilia A (baseline factor VIII activity of 2-40 IU/dL), the clinical impact can be profound. In these patients, inhibitors may also interact with their endogenous factor VIII, resulting in a decrease of the factor VIII plasma level below 1 IU/dL 1 and major bleeding complications. 4 Identification of patients at risk of developing inhibitors may help to prevent this serious complication. However, currently there are no tools available to predict individual inhibitor risk in nonsevere hemophilia patients.The type of mutation in the factor VIII gene (F8) is an important risk factor for inhibitor development. [5][6][7] Nonsevere hemophilia A is generally caused by F8 missense mutations.8 Despite information on large numbers of F8 mutations associated with nonsevere hemophilia A that is collected in international databases, 9,10 it is not possible to calculate the inhibitor risk for specific F8 mutations, as data on exposure days to thera...

Development of inhibitors against factor VIII (FVIII) or factor IX (FIX) in haemophilia patients is one of the most serious complications of repeated exposure to replacement therapy and has major clinical and economic consequences. To evaluate the relationship between inhibitor status of haemophilia patients and their quality of life (QoL) and degree of arthropathy and to compare the orthopaedic status of patients with/without inhibitors. An observational, cross-sectional, case control study enrolling: group A (n = 38), males aged 14-35 years, with severe congenital haemophilia A or B who had inhibitors against FVIII/FIX >5 years; group B (n = 41), as group A, but aged 36-65 years and group C (n = 49), as group A, but without inhibitors. Socio-demographics: medical history, clinical characteristics and QoL were assessed. In groups A and B, 16% and 27% were hospitalized for orthopaedic procedures vs. 4% in group C. Patient mobility was also severely reduced in groups A and B, with 24% and 22% using wheelchairs vs. 4% in group C, and 50% and 51% needing a walking aid vs. 29% in group C. Significantly more joint pain was reported by patients in group A vs. those in group C; clinical/radiological orthopaedic scores were also worse in group A vs. group C. Significantly more joint abnormality was reported by patients in group A vs. group C. The burden of orthopaedic complications and the impact on QoL are more severe in haemophilia patients who have developed inhibitors than in those without inhibitors.

IntroductionAs a result of the new treatment paradigm that the haemophilia community will face with the availability of novel (non‐factor) therapies, an updated consensus on ITI recommendations and inhibitor management strategies is needed.AimThe Future of Immunotolerance Treatment (FIT) group was established to contemplate, determine and recommend the best management options for patients with haemophilia A and inhibitors.Discussion and ConclusionsDespite the considerable success of emicizumab in the management of inhibitor patients, the FIT group still sees the importance of eradicating inhibitors. However, the availability of emicizumab and other non‐factor therapies in the future might impact greatly on how ITI is undertaken. Theoretically, concomitant use of emicizumab and FVIII might allow emicizumab to effectively prevent bleeding with lower dose ITI regimens. This might allow for the greater adoption of low‐dose/low‐frequency FVIII ITI regimens, which may result in a reduced need for central venous access devices while still maintaining a reasonable likelihood of ITI success. The FIT group proposes a new management algorithm for current ITI (without emicizumab) and a hypothetical new approach with the availability of emicizumab. As there are no published data regarding the concomitant use of emicizumab and FVIII for ITI, the FIT Expert group encourages the undertaking of properly conducted prospective studies to explore these approaches further.

We present a retrospective study of immune tolerance treatment (ITT) carried out in 42 Spanish haemophiliac patients. Most of the patients were high responders (39/42), with a median maximum titre of 67 Bethesda units (BU) (range 6-2984). The median inhibitor titre at the start the ITT was 11 BU (range 1-256 BU) and the median age of the patients was 7 years (range 0-57). The mean factor dosage was 140 IU kg bodyweight(-1) day(-1) (range 25-500). In most of the ITTs, plasma-derived factor concentrate of intermediate and high purity was used. The inhibitor was eradicated in 26/38 (68%) of the patients who completed the treatment and two patients changed their status from high to low responders. Multivariate logistic regression analysis showed that three significant variables were associated with the highest probability of success: (i) the use of low factor doses for ITT (< or = 100 IU kg(-1) day(-1); P = 0.0106; 95% CI 0.000289-0.342); (ii) a titre of < 10 BU at start of ITT (P = 0.0286; 95% CI 0.00253-0.7189) and (iii) a lower maximum titre (P = 0.0214; 95% CI 0.98-0.9994).

Summary. Background: The life expectancy of non-severe hemophilia A (HA) patients equals the life expectancy of the non-hemophilic population. However, data on the effect of inhibitor development on mortality and on hemophilia-related causes of death are scarce. The development of neutralizing factor VIII antibodies in non-severe HA patients may dramatically change their clinical outcome due to severe bleeding complications. Objectives: We assessed the association between the occurrence of inhibitors and mortality in patients with non-severe HA. Methods: In this retrospective cohort study, clinical data and vital status were collected for 2709 non-severe HA patients (107 with inhibitors) who were treated between 1980 and 2011 in 34 European and Australian centers. Mortality rates for patients with and without inhibitors were compared. Results: During 64 200 patient-years of follow-up, 148 patients died (mortality rate, 2.30 per 1000 person-years; 95% confidence interval (CI), 1.96-2.70) at a median age of 64 years (interquartile range [IQR], 49-76). In 62 patients (42%) the cause of death was hemophilia related. Sixteen inhibitor patients died at a median age of 71 years (IQR,. In ten patients the inhibitor was present at time of death; seven of them died of severe bleeding complications. The all-cause mortality rate in inhibitor patients was > 5 times increased compared with that for those without inhibitors (ageadjusted mortality rate ratio, 5.6). Conclusion: Inhibitor development in non-severe hemophilia is associated with increased mortality. High rates of hemophilia-related mortality in this study indicate that non-severe hemophilia is not mild at all and stress the importance of close follow-up for these patients.

The discrepancy of the levels of factor VIII activity (FVIII:C) by different assays in some mild and moderate haemophilic A patients has been long known. Specific mutations affecting FVIII:C discrepancies have been described. No consensus exit as to which method most accurately represents the FVIII cofactor function in vivo and which has a better correlation with the haemorrhagic clinical expression. We studied 163 mild A haemophiliacs, and detected discrepancies in 20% of the patients, most of whom presented higher levels of FVIII:C with the one-stage assay. In nine families, the FVIII mutation was found, while three showed mutations not previously described (Leu1978Phe and Ser1791Pro associated with higher levels of FVIII:C by one-stage method; Arg1639His in a patient with low level of FVIII:C by the one-stage, but normal, chromogenic assay). Assessing the level of FVIII:C by different methods could help to learn the possible haemorrhagic expressions of patients.

The Spanish Acquired Hemophilia A (AHA) Registry is intended to update the status of AHA in Spain. One hundred and fifty-four patients were included and retrospectively followed-up for a median time of 12 months. Patients were predominantly male (56.3%), with median age at diagnosis of 74 years. AHA was more frequently idiopathic (44.1%) and autoimmune disorder-associated (31.7%). Thirty-four percent of patients were on antithrombotic therapy at diagnosis. Hemostatic treatment was used in 70% of patients. Recombinant activated factor VII was more frequently infused (60.3% vs 20.6% activated prothrombin complex concentrate). Only one patient did not achieve control of hemorrhage. Complete remission (CR) was achieved by 84.2% of cases after immunosuppressive therapy (IST). Steroids alone were less efficient than the other strategies (68.2% vs 87.2%, P = .049), while no differences existed among these (steroids/cyclophosphamide, 88.5%, vs steroids/calcineurin inhibitors, 81.2%, vs rituximab-based regimens, 87.5%). Female sex and high inhibitor levels influenced CR negatively. Thirty-six deaths (23.8%) were reported. Main causes of death were infection (15 patients, 9.9%) and hemorrhage (5 patients, 3.3%). All hemorrhage-related and half the infection-related deaths occurred within two months of diagnosis. Prior antithrombotic therapy was inversely associated with survival, irrespective of age. Median age of non-survivors was significantly higher (79 vs 73 years in survivors). Patients dying of infection were older than the other non-survivors (85 vs 78 years). In summary, fatal infection in the first months is common in our series. Antithrombotic therapy is associated with mortality. Particular care should be taken to avoid misdiagnosis.

The intention of the 'clinical and echographical protocol of evaluation the efficacy of recombinant activated factor VII in the haemarthrosis' (EFFISEVEN protocol) was to provide an extensive study of the evolution of haemarthrosis, and second, of its repercussions on the degenerative process of joints. The clinical evaluation of haemarthroses and their evolution is based on a well-established methodology, although very few studies have sought to determine the correlation between pain, mobility and the objective data regarding the haemorrhage. We believe that it is necessary to unify criteria and that the EFFISEVEN protocol may contribute data that improve standards which, in turn, will influence the degenerative process of joints, and consequently affect the quality of life of haemophilia patients with inhibitors. Echographical control of haemarthrosis is an objective method that allows control over how the haemorrhage evolves and also helps in the identification of rebleeding. Therefore, its use adds a new dimension to patient management strategies. Techniques used to monitor recombinant activated factor VII (rFVIIa) treatment require further study, although preliminary results guarantee their efficacy.