Determinants of bleeding before and during immune tolerance in 222 boys with severe hemophilia A and inhibitors >5 BU.

ABSTRACT: Prevention of bleeding and its consequences is the main goal of hemophilia treatment and determines treatment choices for patients who develop inhibitors. To assess bleeding before and during immune tolerance induction (ITI) and its association with ITI regimen and inhibitor titer, we selected and analyzed data on patients receiving high-titer inhibitors from the international prospective PedNet cohort study. In total, 222 patients with severe hemophilia A and inhibitor titers of >5 Bethesda units (BU) were followed from the first positive to the first negative inhibitor result (median overall follow-up, 1.7 years). Mean annual (joint) bleeding rates (AJBR) and 95% confidence intervals (CIs) were compared according to treatment and inhibitor titer using multivariable negative binomial regression. Before ITI, 115 patients showed an ABR of 6.1 (5.0-7.4) and an AJBR 2.6 (2.1-3.2). Bleeding was independent of inhibitor titer. During ITI, 202 patients had an ABR of 4.4 (3.9-5.1) and an AJBR of 1.7 (1.5-2.0). AJBR during ITI increased with inhibitor titer (hazard ratio [HR] for ≥200 BU vs 5 to 39 BU [4.9; CI, 3.2-7.4]) and decreased with daily ITI infusions (HR, 0.4; CI, 0.3-0.6) or activated prothrombin complex concentrate prophylaxis (HR, 0.4; CI, 0.2-0.8), whereas ITI dose and recombinant activated factor VII prophylaxis did not independently affect bleeding. These data provide evidence for a protective effect of repeated FVIII infusions (ITI) on bleeding in patients who have developed inhibitors; these data should be used to plan ITI and/or serve as a comparator for prophylaxis with nonreplacement therapy.

Matching-Adjusted Indirect Comparison of Efficacy and Consumption of rVIII-SingleChain Versus Two Recombinant FVIII Products Used for Prophylactic Treatment of Adults/Adolescents with Severe Haemophilia A.

INTRODUCTION: Given the relatively small number of patients with haemophilia A, head-to-head comparisons between recombinant FVIII (rFVIII) products are difficult to conduct. This study compared the efficacy and consumption of rVIII-SingleChain (lonoctocog alfa, AFSTYLA®) with rAHF-PFM (octocog alfa, Advate®) and rFVIIIFc (efmoroctocog alfa, Elocta®), for the prophylaxis and treatment of bleeding episodes in previously treated adolescents/adults with severe haemophilia A, through a matching-adjusted indirect comparison (MAIC). METHODS: A systematic literature review identified published clinical trials for rAHF-PFM and rFVIIIFc. Individual patient data for rVIII-SingleChain were used to match baseline patient characteristics to those from published trials, using an approach similar to propensity score weighting. After matching, annualized bleeding rates (ABR), percentage of patients with zero bleeds, and rFVIII consumption were compared across trial populations. RESULTS: Published data were identified from two rAHF-PFM trials and one rFVIIIFc trial. rVIII-SingleChain had similar ABR (risk ratio [RR]: 0.74 [0.16; 3.48]; RR: 1.18 [0.85; 1.65]) and percentage of patients with zero bleeds (odds ratio [OR]: 1.34 [0.56; 3.22]; OR: 0.78 [0.47; 1.31]) versus rAHF-PFM and rFVIIIFc, respectively. Annual rVIII-SingleChain consumption was significantly lower than rAHF-PFM (mean difference: - 1507.66 IU/kg/year [- 2011.71; - 1003.61]) and equivalent to rFVIIIFc (RR: 0.96 [0.62; 1.49]). CONCLUSION: Although limited to published information for comparator trials, these results suggest that with an annualized rFVIII consumption comparable to rFVIIIFc, but significantly lower than rAHF-PFM, routine prophylaxis with rVIII-SingleChain is able to maintain a similar ABR and percentage of patients with zero bleeds, attesting to the long-acting nature of rVIII-SingleChain.

It is difficult to directly compare different recombinant FVIII products in head-to-head studies because there are few patients with haemophilia A. This study aimed to indirectly compare the efficacy and consumption of different recombinant FVIII products in the prophylactic treatment of haemophilia A using published clinical data. A proven method for performing indirect comparisons of products is referred to as a matching-adjusted indirect comparison. Using this approach, we were able to compare rVIII-SingleChain with two other recombinant FVIII products (rAHF-PFM and rFVIIIFc). Our results suggest that annual FVIII consumption with rVIII-SingleChain is comparable to rFVIIIFc, but is significantly lower than rAHF-PFM, while maintaining a similar bleeding rate. These results highlight the long-acting nature of the product.

Recanalization strategies in childhood stroke in Germany.

Childhood arterial ischemic stroke (CAIS) is a rare event. Diverse etiologies, risk factors, symptoms and stroke mimics hamper obtaining a fast diagnosis and implementing immediate recanalization strategies. Over a period of 3 years (2015-2017), the data of 164 pediatric patients (> 28 days of life-18 years) with a first episode of AIS were submitted to a hospital-based nationwide surveillance system for rare disorders (ESPED). We report a subgroup analysis of patients who have undergone recanalization therapy and compare these data with those of the whole group. Twenty-eight patients (17%) with a median age of 12.2 years (range 3.3-16.9) received recanalization therapy. Hemiparesis, facial weakness and speech disturbance were the main presenting symptoms. The time from onset of symptoms to confirmation of diagnosis was significantly shorter in the intervention group (4.1 h vs. 20.4 h, p ≤ 0.0001). Only in one patient occurred a minor bleed. Cardiac disease as predisposing risk factor was more common in the recanalization group. Recanalization therapies are feasible and increasingly applied in children with AIS. High awareness, timely diagnosis and a large amount of expertise may improve time to treatment and make hyperacute therapy an option for more patients.

Inhibitor incidence in an unselected cohort of previously untreated patients with severe haemophilia B: a PedNet study.

The incidence of FIX inhibitors in severe hemophilia B (SHB) is not well defined. Frequencies of 3-5% have been reported but most studies to date were small, including patients with different severities, and without prospective follow-up for inhibitor incidence. Study objective was to investigate inhibitor incidence in patients with SHB followed up to 500 exposure days (ED), the frequency of allergic reactions, and the relationship with genotypes. Consecutive previously untreated patients (PUPs) with SHB enrolled into the PedNet cohort were included. Detailed data was collected for the first 50 ED, followed by annual collection of inhibitor status and allergic reactions. Presence of inhibitors was defined by at least two consecutive positive samples. Additionally, data on factor IX gene mutation was collected. 154 PUPs with SHB were included; 75% were followed until 75 ED, and 43% until 500 ED. Inhibitors developed in 14 patients (7 high-titre). Median number of ED at inhibitor manifestation was 11 (IQR 6.5-36.5). Cumulative inhibitor incidence was 9.3% (95%CI 4.4-14.1) at 75 ED, and 10.2% (5.1-15.3) at 500 ED. Allergic reactions occurred in 4 (28.6%) inhibitor patients. Missense mutations were most frequent (46.8%) overall but not associated with inhibitors. Nonsense mutations and deletions with large structural changes comprised all mutations among inhibitor patients and were associated with an inhibitor risk of 26.9% and 33.3%, respectively. In an unselected, well-defined cohort of PUPs with SHB, cumulative inhibitor incidence was 10.2% at 500 ED. Nonsense mutations and large deletions were strongly associated with the risk of inhibitor development. The PedNet Registry is registered at clinicaltrials.gov; identifier: NCT02979119.

Optimizing the management of patients with haemophilia A and inhibitors in the era of emicizumab: Recommendations from a German expert panel.

Standard treatment of haemophilia A is based on replacing the missing coagulation factor VIII (FVIII) to treat and prevent bleeding episodes. The most challenging complication of FVIII therapy is the development of neutralizing antibodies (inhibitors) that can render treatment ineffective. Eradication of the inhibitor through immune tolerance induction (ITI) remains the most effective strategy for managing these patients. Bypassing agents can be used to help restore haemostasis in inhibitor patients. Several novel agents have recently been developed, such as the FVIII mimetic agent emicizumab, which has been effective in reducing the annualized bleeding rate in haemophilia A patients with inhibitors. When coadministered with repetitive high doses of activated prothrombin complex concentrate (ie >100 U/kg/d for ≥24 hours), emicizumab was associated with thrombotic microangiopathy and thrombosis events. As a consequence the United Kingdom Haemophilia Centres Doctors' Organisation (UKHCDO) issued the first guidance on the treatment of bleeding episodes in patients receiving emicizumab. To build on and extend this work, a panel of German haemophilia specialists met to discuss the UK guidance, review current evidence and provide additional guidance for German healthcare professionals on how to optimize the management of patients with haemophilia A receiving emicizumab. Recommendations are provided on the use of bypassing and other agents to manage breakthrough bleeding, ITI in the emicizumab era, haemostatic support during surgery and issues relating to laboratory monitoring.

Practical Guidance of the GTH Haemophilia Board on the Use of Emicizumab in Patients with Haemophilia A.

Emicizumab has been approved for bleeding prophylaxis in patients with haemophilia A (PWHAs) with or without inhibitors. Because of substantial differences between factor VIII (FVIII) and Emicizumab, the 'Ständige Kommission Hämophilie' of the German, Austrian, Swiss Society for Thrombosis and Haemostasis Research (GTH) established a practical guidance for the use of Emicizumab in PWHAs. A systematic literature research was conducted in PubMed. Based on this and on personal experience, this practical guidance has been developed. Each single statement has been discussed among members of the 'Ständige Kommission Hämophilie' and revised accordingly. The final set of recommendations has been approved by all authors analogous to the Delphi method. This practical guidance is provided for physicians treating PWHAs with regard to general aspects, patient education, bleeding treatment, surgery, use of Emicizumab in previously untreated patients (PUPs), patients with newly diagnosed inhibitors and elderly patients. Patients should be treated in expert centres and adequate laboratory tests to monitor Emicizumab levels, FVIII replacement and inhibitors should be available. Early experience of immune tolerance induction protocols integrating Emicizumab is reviewed, and the limited experience in PUPs and very young children is described. So far, no thromboembolic complications have been reported with the concomitant use of FVIII or recombinant activated FVII for bleeding treatment or surgery. Activated prothrombin complex concentrate doses of >100 U/kg for >24 hours should be avoided whenever possible because of the high risk of thrombosis and/or thrombotic microangiopathy. In conclusion, this study is designed to support haemophilia physicians using Emicizumab in physicians treating hemophilia and using (PWHAs). With further post-marketing experience and trials, regular updates are necessary.

Childhood Arterial Ischaemic Stroke: Clinical Presentation, Risk Factors and Management.

Childhood arterial ischaemic stroke (AIS) is a rare, but potentially life-threatening event which requires early diagnosis and adequate treatment. The reported significant time delay to childhood AIS diagnosis may be associated with low awareness, the more nonspecific clinical presentation as well as difficult clinical differentiation to more common "stroke mimics" and a less established "acute care structure" with delayed access to proper neuroimaging. Compared with adult stroke care, experiences with acute reperfusion therapies like thrombolysis and mechanical thrombectomy are promising but limited and not based on clinical trials. The etiological work-up is absolutely essential, as the child's individual risk profile determines acute management, secondary prevention, risk of recurrence and outcome. Follow-up care should be organized in a multidisciplinary setting covering all bio-psycho-social aspects to achieve the best integration of the child into its educational, later professional and social environments.

Health Care Transition of Adolescents and Young Adults with Haemophilia: the Situation in Germany and the Munich experience.

Patients suffering from haemophilia encounter various phases in life, in which individual needs, life situations, and self- and disease perception change rapidly. One of these phases spans from the beginning of puberty until early adulthood, in which individuals gain self-responsibility and reach independence and autonomy. In this challenging time that determines future health, adolescents and young adults need sustainable familiar and professional support. A change in health care team and treatment centre may expose adolescent patients to threats but also provides the possible opportunity to be well prepared. While there is emerging evidence that the so-called health care transition programmes are effective in maintaining quality of care in other disease areas, transition programmes for patients with haemophilia are still rare in Germany, and the evidence is limited. We describe the situation in Germany, discuss our experience in Munich and review some of the available guidance; we conclude that transition programmes should become a standard of care in haemophilia.

How Do I Counsel Parents of a Newly Diagnosed Boy with Haemophilia A?

With the recent approval of improved therapeutic options for patients suffering from haemophilia A such as the extended half-life, recombinant factor concentrates, non-factor VIII replacement therapies like Emicizumab and after consideration of the currently running clinical trials investigating even more advanced approaches, counselling of parents of a newly diagnosed boy with haemophilia A has not become less demanding. Parents need to be informed about the pathophysiology, the chronic nature and the potential risks that are commonly associated with this disease and its treatment, depending on disease severity. Above all, the safety and efficacy of the medicinal drug(s) to be used are of utmost importance, given the impact of non-virus-inactivated plasma-derived factor concentrates in the 1980s. As a consequence, the subsequent development and registration of recombinant clotting factors from mammalian, and recently, even human, cell cultures are seen by many as a breakthrough, although, regarding the product-type-dependent development of inhibitors in previously untreated patients, the discussion is still open. Clinical data for the humanised bispecific antibody Emicizumab in paediatric patients below 2 years of age without inhibitors who suffer from severe haemophilia A are currently limited.

Arterial ischemic stroke in infants, children, and adolescents: results of a Germany-wide surveillance study 2015-2017.

OBJECTIVE: Childhood arterial ischaemic stroke (AIS) is rare, but causes significant morbidity and mortality. We aimed to investigate incidence, age-dependent clinical presentation, and risk factors and to discuss the medical care situation in Germany. METHODS: This prospective epidemiological study was conducted via ESPED (Erhebungseinheit für Seltene Pädiatrische Erkrankungen in Deutschland), a hospital-based German nation-wide surveillance unit for rare pediatric diseases. Children aged 28 days-18 years with first AIS between January 2015 and December 2017 were included. RESULTS: In the 3-year period, 164 children were reported. Incidence showed peaks in infants, children < 2 years of age, and adolescents (12-18 years), with a significant male predominance observed in adolescents only. Independent of age, most children (91%) presented with focal symptoms, particularly with acute hemiparesis. The occurrence of seizures in infants (57%) and more nonspecific symptoms in school-children and adolescents (54%) is considered noteworthy. Prothrombotic states (34%), cardiac disorders (29%), and arteriopathies (19%) were the most frequently identified risk factors. The majority of children (72/131, thus 55%) were discharged home after acute care phase. At time of discharge, most common neurological symptoms were hemiparesis (42%), facial palsy (15%), and speech disturbance (12%). CONCLUSION: This study provides population-based data of childhood AIS which may be useful for further research. The improvement of acute stroke management is needed for children, but also the standardization of post-stroke care in the outpatient setting has to be structured. Considering the higher stroke incidence in (male) adolescents, it is advisable to combine research activities in adolescents and young adults.

Prevalence of Obesity in Young Patients with Severe Haemophilia and Its Potential Impact on Factor VIII Consumption in Germany.

Similar to the general population, overweight and obesity have increasingly become a medical and economic burden also in patients with haemophilia in industrialized nations. In this study in seven German haemophilia centres, we identified a prevalence of overweight and obesity of 25.2% among 254 young patients <30 years (median: 13 years; range: 0-30 years) with severe haemophilia A and without a history of inhibitors. The median FVIII dosage based on bodyweight was significantly higher in normal weight compared with overweight or obese patients (96.9 vs. 72.9 IU/kg/week, respectively; p < 0.0001). This suggests that an individualized dosing regime which might be based on FVIII pharmacokinetics, physical activity and pre-existing haemophilic arthropathy is applied rather than dosing by bodyweight only. The bleeding rates observed in obese (median: 1; range: 0-17) versus normal weight patients (median: 2; range: 0-28) did not differ significantly (p = 0.057). Lower bleeding rates might be due to reduced activity or expected higher FVIII plasma levels in overweight patients. Due to the increasing prevalence of overweight/obesity in patients with haemophilia an interdisciplinary approach for individualized haemophilia treatment and weight loss programmes might be helpful for optimal and economical treatment for this group of patients.

Impact of Adopting Population Pharmacokinetics for Tailoring Prophylaxis in Haemophilia A Patients: A Historically Controlled Observational Study.

BACKGROUND: Performing individual pharmacokinetics (PK) studies in clinical practice can be simplified by adopting population PK-based profiling on limited post-infusion samples. The objective of this study was to assess the impact of population PK in tailoring prophylaxis in patients with haemophilia A. PATIENTS AND METHODS: Individual weekly treatment plans were developed considering predicted plasma factor activity levels and patients' lifestyle. Patients were trained using a visual traffic-light scheme to help modulate their level of physical activity with respect to factor infusions timing. Annualized joint bleeding rate (ABJR), haemophilia-specific quality of life questionnaire for adults (Haemo-QoL-A) and factor utilization were measured for 12 months before and after tailoring, compared within patients and analysed separately for those previously on prophylaxis (P), situational prophylaxis (SP) or on-demand (OD). RESULTS: Sixteen patients previously on P, 10 on SP and 10 on OD were enrolled in the study. The median (lower, upper quartile) ABJR changed from 2.0 (0, 4.0) to 0 (0, 1.6) for P (p = 0.003), from 2.0 (2.0, 13.6) to 3.0 (1.4, 7.2) for SP (p = 0.183) and from 16.0 (13.0, 25.0) to 2.3 (0, 5.0) for OD (p = 0.003). The Haemo-QoL-A total score improved for 58% of P, 50% of SP and 29% of OD patients. Factor utilization (IU/kg/patient/year) increased by 2,400 (121; 2,586) for P, 1,052 (308; 1,578) for SP and 2,086 (1,498; 2,576) for OD. One of 138 measurements demonstrated a factor activity level below the critical threshold of 0.03 IU/mL while the predicted level was above the threshold. CONCLUSION: Implementing tailored prophylaxis using a Bayesian forecasting approach in a routine clinical practice setting may improve haemophilia clinical outcomes.

Symptom patterns in childhood arterial ischemic stroke: Analysis of a population-based study in Germany.

HINTERGRUND: Die zeitliche Verzögerung zwischen Symptombeginn und Diagnose ist eine Herausforderung in der Behandlung von Kindern mit arteriell ischämischem Schlaganfall. Frühere Studien zur klinischen Präsentation beschäftigten sich v. a. mit kumulativen Symptomen. ZIELSETZUNG: Ziel dieser Studie ist es, mögliche Symptommuster aufzuzeigen. METHODEN: In einer aktiven Beobachtungsstudie zwischen 01/2015 und 12/2016 (ESPED-Studie) wurden Kinder mit Erstdiagnose eines arteriell ischämischen Schlaganfalls eingeschlossen. Isoliert auftretende Erstsymptome wurden verschiedenen Symptomkombinationen gegenübergestellt. Zudem wurde untersucht, inwieweit ein als "akut" oder "progredient" klassifiziertes Auftreten der Symptome Rückschlüsse auf die zugrundeliegende Ätiologie erlaubt. ERGEBNISSE: Es wurden 99 Kinder in die Studie eingeschlossen. Unabhängig vom Alter traten überwiegend fokale Symptome auf (86%). Krampfanfälle als Initialsymptom wurden insbesondere bei Säuglingen beschrieben (67%), wohin-gegen diffuse, unspezifische Symptome vor allem bei Vorschulkindern (38%) und älteren Kindern (59%) auftraten. Isoliert traten fokale Symptome bei 37 Kindern auf, 48 Kinder zeigten zusätzlich unspezifische Symptome, darunter auch 9 Kinder mit Krampfanfällen. Isolierte unspezifische Symptome zeigten sich lediglich bei 7 Kindern, 2 Kinder wurden nur mit Krampfanfällen symptomatisch. Die Akuität des Symptombeginns wurde bei 53/78 als "akut" und bei "25/78 Fällen als "progredient" klassifiziert, lieferte jedoch keinen Hinweis auf die zugrundeliegende Ätiologie. SCHLUSSFOLGERUNG: Jedes neue fokal neurologische Defizit sollte unabhängig vom Auftreten (isoliert oder kombiniert, akut oder progredient) an einen kindlichen Schlaganfall denken lassen. BACKGROUND: Time delay between onset of clinical symptoms and diagnosis is a challenge in childhood arterial ischemic stroke. Most previous studies reported cumulative symptoms. OBJECTIVE: We attempted to identify typical symptom patterns and assessed their emergence in childhood stroke. METHODS: Prospective active surveillance in ESPED, a hospital based Pediatric Surveillance Unit for rare diseases in Germany, between January 2015 and December 2016. Case definition: first diagnosis of a radiologically confirmed arterial ischemic stroke. Symptom patterns were identified as occurring in isolation or in combination. We distinguished acute vs. progressive onset. We ascertained risk factors to identify the possible etiology. RESULTS: 99 children with childhood arterial ischemic stroke were reported. Focal symptoms were the predominant presenting feature (86%), independent of age. Seizures were more often seen in infants < 1 year (67%), whereas diffuse symptoms were more present in pre-school children (38%) and older children (59%). 37 children had focal features alone and 48 additional non-specific features, including 9 with seizures. Isolated non-specific features accounted for 7 cases, and 2 children had (focal) seizures as the only symptom. In 77% of all cases at least one risk factor was identified. The emergence of symptoms was acute in 53/78 cases and progressive in 25/78 cases. The pattern of emergence was unrelated to the underlying etiology. CONCLUSIONS: Any new focal neurological deficit in isolation, or associated with seizures or further non-specific symptoms should alert to childhood stroke.

Infrared Thermography as a Non-Invasive Tool to Explore Differences in the Musculoskeletal System of Children with Hemophilia Compared to an Age-Matched Healthy Group.

Recurrent joint bleeds and silent bleeds are the most common clinical feature in patients with hemophilia. Every bleed causes an immediate inflammatory response and is the leading cause of chronic crippling arthropathy. With the help of infrared thermography we wanted to detect early differences between a group of clinical non-symptomatic children with hemophilia (CWH) with no history of clinically detected joint bleeds and a healthy age-matched group of children. This could help to discover early inflammation and help implement early treatment and preventative strategies. It could be demonstrated that infrared thermography is sensitive enough to detect more signs of early inflammatory response in the CWH than in healthy children. It seems to detect more side differences in temperature than clinical examination of silent symptoms detects tender points. Silent symptoms/tender points seem to be combined with early local inflammation. Using such a non-invasive and sensor-based early detection, prevention of overloading and bleeding might be achieved.

Risk factors in childhood arterial ischaemic stroke: Findings from a population-based study in Germany.

OBJECTIVE: Acute treatment of childhood arterial ischaemic stroke and prevention strategies for recurrent stroke episodes depend strongly on each child's individual risk profile. The aim of this study is to characterize risk factors for childhood stroke, their occurrence in isolation or combination, and to identify possible common risk factor patterns. METHODS: This population-based study was conducted via ESPED, a surveillance unit for rare paediatric diseases in Germany. Children aged >28days and <18 years with an acute arterial ischaemic stroke occurring between January 2015 and December 2016 were included. RESULTS: Among 99 reported children with arterial ischaemic stroke, 56 children were male. Male predominance was significant in adolescents from 12 years old onward. Arterial ischaemic stroke was more common in very young children <2 years of age and in adolescence. No risk factor was identified in 27 children. Hypercoagulable states (29%), cardiac disorders (24%), and arteriopathies (21%) were the most common risk factors. Some risk factor categories were more likely to be identified in isolation (i.e. cardiac disorders, prothrombotic abnormalities and chronic head and neck disorders) than others. The number of risk factors (n = 0-4) per patient and risk factor categories did not differ by age. CONCLUSION: Although we could not identify common patterns of risk factor combinations, several risk factors occurred more likely in isolation than others. Further research should focus on the impact of isolated presumed childhood stroke risk factors like certain prothrombotic abnormalities, migraine or a patent foramen ovale. With regard to different age groups, stroke mechanisms in male adolescents require particular attention.

Risk Factors for the Progression from Low to High Titres in 260 Children with Severe Haemophilia A and Newly Developed Inhibitors.

In children with severe haemophilia A, inhibitors to factor VIII (FVIII) usually develop during the first 50 treatment exposure days and are classified as low or high titre depending on the peak inhibitor titre being greater or less than 5 Bethesda units/mL (BU/mL). Classification of the inhibitor may change with time, as some low-titre inhibitors progress to high titre following re-exposure to FVIII concentrate. The aim of this study was to investigate potential risk factors for such a progression in children with severe haemophilia A and newly diagnosed inhibitors. This study was a follow-up study of the PedNet Registry and included 260 children with severe haemophilia A and inhibitors born between 1990 and 2009 and recruited consecutively from 31 haemophilia centres. Clinical and laboratory data were collected from the date of each child's first positive inhibitor test for at least 3 years. At the time of first positive inhibitor test, 49% (n = 127) had low-titre inhibitors, with 50% of them progressing to high titre and only 25% maintaining low titres. The FVIII gene (F8) mutation type was known in 247 patients (95%), and included 202 (82%) null mutations. The progression to high-titre inhibitors was associated with null F8 mutations (odds ratio [OR]: 2.6; 95% confidence interval [CI]: 1.0­6.5), family history of inhibitors (OR: 7.2; 95% CI: 1.8­28.4) and the use of high-dose immune tolerance induction, defined as ≥100 IU FVIII concentrate/kg/d (OR: 3.9; 95% CI: 1.5­10.0). These results suggest that high-dose immune tolerance induction should be avoided as the initial strategy in patients who develop low-titre FVIII inhibitors.

Intracranial haemorrhage in children and adolescents with severe haemophilia A or B - the impact of prophylactic treatment.

The discussion of prophylactic therapy in haemophilia is largely focused on joint outcomes. The impact of prophylactic therapy on intracranial haemorrhage (ICH) is less known. This study aimed to analyse ICH in children with haemophilia, with a focus on different prophylaxis regimens and sequelae of ICH. We conducted a multicentre retrospective and prospective study that included 33 haemophilia centres from 20 countries. Inclusion criteria were children and adolescents born between 1993 and 2014, with severe haemophilia A or B without inhibitors. Participants were categorized by prophylaxis regimen: full, partial or none, based on dose and dose frequency of regular infusions. The cohort study included 1515 children: 29 cases of ICH over 8038 patient years were reported. The incidence of ICH in the prophylaxis group, 0·00033 cases of ICH/patient year, was significantly lower compared to the no prophylaxis group, 0·017 cases of ICH/patient year (RR 50·06; P < 0·001) and the partial prophylaxis group, 0·0050 cases of ICH/patient year (RR 14·92; P = 0·007). In the on-demand-group, 8% (2/24) children with ICH died and 33% had long-term sequelae, including intellectual and behavioural problems, paresis and epilepsy. Children on regular, frequent prophylaxis have a low risk of ICH compared to those using non-frequent or no prophylaxis.