Abstract

BACKGROUND To account for interindividual variability in the pharmacokinetics (PK) of factor concentrates, PK-guided dosing is increasingly implemented in haemophilia patients. Calculations are based on provided label potency, but legislation allows a potency difference of ±20% between label and actual potency. It is unknown if these differences affect PK guidance. AIM: Explore the effects of potency differences on individual factor VIII (FVIII) PK parameters and the prediction of FVIII trough levels of dosing regimens. METHODS We analyzed individual preoperative PK profiling data from severe and moderate haemophilia A patients included in the OPTI-CLOT randomized controlled trial. Label and actual potency were compared, with data on potency provided by pharmaceutical companies. For both potencies, individual PK parameters were estimated and concentration-time curves were constructed by nonlinear mixed-effects modelling. Finally, we explored the effect of both the identified and the maximum legislated potency difference on predicted FVIII trough levels infused in a low and high dose regimen. RESULTS In 45/50 included patients, actual potency was higher than its label potency. The median potency difference was 6.0% (range -9.2% to 18.4%) and resulted in varying individual PK parameter estimates but practically identical FVIII concentration-time curves. As expected, predicted FVIII trough levels were linearly correlated to the actual dose. CONCLUSION It is not necessary to take potency differences into account when applying PK guidance of FVIII concentrates in haemophilia A patients. However, when the patient is switched to another FVIII batch after PK-guided dosing, trough levels may deviate ±20% from calculations based on label dose.

Abstract

BACKGROUND Von Willebrand Disease (VWD) is a common inherited bleeding disorder. Patients with VWD suffering from severe bleeding may benefit from the use of secondary long-term prophylaxis. AIM: Systematically summarize the evidence on the clinical outcomes of secondary long-term prophylaxis in patients with VWD and severe recurrent bleedings. METHODS We searched Medline and EMBASE through October 2019 for relevant randomized clinical trials (RCTs) and comparative observational studies (OS) assessing the effects of secondary long-term prophylaxis in patients with VWD. We used Cochrane Risk of Bias (RoB) tool and the RoB for Non-Randomized Studies of interventions (ROBINS-I) tool to assess the quality of the included studies. We conducted random-effects meta-analyses and assessed the certainty of the evidence using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. RESULTS We included 12 studies. Evidence from one placebo controlled RCT suggested that VWD prophylaxis as compared to no prophylaxis reduced the rate of bleeding episodes (Rate ratio [RR], .24; 95% confidence interval [CI], .17-.35; low certainty evidence), and of epistaxis (RR, .38; 95%CI, .21-.67; moderate certainty evidence), and may increase serious adverse events RR 2.73 (95%CI .12-59.57; low certainty). Evidence from four before-and-after studies in which researchers reported comparative data suggested that VWD prophylaxis reduced the rate of bleeding (RR .34; 95%CI, .25-.46; very low certainty evidence). CONCLUSION VWD prophylaxis treatment seems to reduce the risk of spontaneous bleeding, epistaxis, and hospitalizations. More RCTs should be conducted to increase the certainty in these benefits.

Abstract

INTRODUCTION Low dose factor VIII prophylactic therapy in hemophilia has not been well established till date. This randomized controlled trial compared the efficacy of twice vs. thrice weekly schedule of low dose prophylactic factor VIII in children with hemophilia A as evaluated by the bleeding rate and clinico-radiological evaluation. METHODS Thirty-three children with severe hemophilia A (≤18 years) were randomized into two groups. Baseline evaluation included detailed history, clinical (HJHS 2.1 score and FISH score) and radiological examination (Pettersson score and ultrasound score). Group 1 received twice weekly factor VIII prophylaxis while group 2 received thrice weekly factor VIII prophylaxis, the dose being 10 U/kg in both groups. All participants were followed up over next 6 months to one year. Data regarding acute bleeding episodes and repeat clinico-radiological assessment at the end of follow up were recorded. RESULTS We analyzed 14 children in twice weekly prophylaxis group and 16 children in thrice weekly prophylaxis group. Statistically insignificant difference was found between the bleeding rates in both the groups after prophylaxis with the median values of monthly bleeding rate being 0.17 and p-value of 0.79. The differences between the initial and final clinical and radiological scores within each group were found to be statistically significant. There was no significant difference in the clinical and radiological scores in between the groups. CONCLUSION Twice weekly FVIII therapy is effective, easily administered prophylactic schedule to prevent long-term complications of hemophilia A. Lay summaryHemophilia A is one of the most common congenital coagulation factor deficiencies. Low dose factor VIII prophylaxis is recommended for hemophilia in resource-poor settings to reduce the bleeding episodes and improve the quality of life, although the optimal schedule for the same has not been well established. A randomized controlled trial on 33 children with hemophilia A (≤18 years) was done to compare the efficacy of twice versus thrice weekly schedule of prophylactic factor VIII. Group 1 received twice weekly factor VIII prophylaxis while group 2 received thrice weekly factor VIII prophylaxis, the dose in both groups being 10 U/kg. They were evaluated by the bleeding rate and clinical (HJHS 2.1 score and FISH score) and radiological scores (Pettersson score and ultrasound score). All participants were followed up over next 6 months to one year. Data regarding acute bleeding episodes and repeat clinico-radiological assessment at end of follow up were recorded. When analyzed, statistically insignificant difference was found between the bleeding rates after the two prophylaxis regimes. There was a significant improvement between initial and final clinical and radiological scores in both the groups and no difference was recorded in between the groups. To conclude, twice weekly FVIII therapy is effective, easily administered prophylactic schedule to prevent long-term complications of hemophilia A.

Abstract

BACKGROUND Despite the advantages of prophylactic treatment for hemophilia, patients tend to discontinue or not adhere to it because of several challenges such as long-term use, high cost, young patients transitioning to adolescents, and switch to self-infusion or self-care. The goal of this systematic literature review is to emphasize adherence to and efficiency of prophylactic treatment in adults. METHODS A literature review was conducted in PubMed, Embase, and Cochrane databases until April 2021 according to PRISMA guidelines, and the protocol was registered with PROSPERO (CRD42020220085). Studies evaluating the efficacy of prophylaxis in enhancing the quality of life were included. RESULTS A total of 31 articles involving 2379 patients with hemophilia were included in this systematic review. Of these, 26 studies were observational, questionnaire-based studies, and 5 were randomized controlled trials. The majority of studies reported lower annualized bleeding rates in patients receiving prophylaxis compared with those receiving on-demand treatment or those who discontinued prophylaxis. Standard-dose prophylaxis was reported to be effective in most of the studies. In developing countries like China, data suggest that low doses were administered because of limited available resources. However, standard dose or individualized prophylaxis should be provided to prevent joint damage in the long term. Compared with adults, greater adherence to treatment was observed in patients aged < 16 years. CONCLUSION This systematic review emphasizes the importance of adherence to prophylaxis among young adults transitioning from childhood. In countries like China, low-dose prophylaxis can help in preventing joint bleeds in the short term, but in the long term, standard-dose therapy has shown high adherence among young adults and better joint health, in turn improving the quality of life.

Abstract

INTRODUCTION In underdeveloped countries, patients with hemophilia often experience repetitive ankle joint hemorrhages due to a shortage of coagulation factors (factor VIII [FVIII] and factor IX [FIX] for hemophilia A and B, respectively). AREAS COVERED This is a narrative literature review in which we searched the Cochrane Library and MEDLINE for articles related to ankle arthrodesis in patients with hemophilia. The searches covered the period from the databases´ inception to February 28, 2021. In the event of unsuccessful hematologic prophylaxis and conservative measures (e.g., analgesics, cyclooxygenase-2 inhibitors, taping, intra-articular injections of hyaluronic acid and corticosteroids, physical and rehabilitation medicine, orthoses, radiosynovectomy, and joint-preserving surgery (e.g., removal of the distal tibia by open surgery or by arthroscopic surgery, joint debridement by arthroscopic surgery), the only surgical solution is ankle arthrodesis, which does not preserve the ankle joint. EXPERT OPINION Ankle pain is reduced after ankle arthrodesis (75% of patients experience no pain). Approximately 5% of patients require reoperation due to lack of fusion, and deep infection occurs in 2.5%. After tibiotalar fusion, a self-reported activity scale shows that approximately 12% of patients improve, 9% worsen, and 79% show no improvement. The results of ankle arthrodesis therefore appear to be poor.

Abstract

Female carriers are more common than males with hemophilia and unrecognized factor VIII or IX deficiency is associated with intrauterine growth retardation, epidural hematomas, blood transfusion, and peripartum hemorrhage. A review was conducted to assess the evidence for professional society recommendations for > 50% factor levels during labor. Two searches of Pubmed, CINAHL, Cochrane, and Google Scholar were completed in October 2019. The first for case reports and series described neuraxial techniques in patients with hemophilia-regardless of sex, age, or pregnant status. The second for case reports and series described bleeding outcomes of parturients with hemophilia. Primary outcomes were diagnosis of neuraxial hematoma (first search) and postpartum bleeding complications (second search). Thirteen articles (n = 134) described neuraxial techniques in patients with hemophilia. Neuraxial hematoma with paraplegia occurred in 3/134 patients-all had a factor level of 1%. Nineteen articles (2712 deliveries in 2657 women) described bleeding outcomes. Postpartum hemorrhage occurred in 7.1% (193/2712) of deliveries, of which 60% necessitated blood transfusion. Postpartum bleeding complications were twice as likely (51.0% [25/49] vs. 25.6% [52/203], P < 0.001) with factor activity < 50%. Therefore, factor levels should be assessed and increased above 50% prior to neuraxial technique and delivery.Trial registration: PROSPERO 2018 CRD42018110215.

Abstract

INTRODUCTION Obesity alters the pharmacokinetic (PK) properties of drugs making it difficult to determine the appropriate dose when administering weight-based medications. Alternative descriptors of body weight, such as lean body mass (LBM) and ideal body weight (IBW), are sometimes used in these situations. METHODS We performed a single-centre, randomized, controlled, open-label, 3 × 3 crossover trial to determine whether recombinant factor VIII (rFVIII) dosing based on LBM and IBW achieves a targeted FVIII recovery with better precision than based on total body weight (TBW) in overweight and obese, adult males with haemophilia A. Participants were randomized to 1 of 6 possible FVIII concentrate dosing sequence scenarios (TBW, LBM and IBW). Recombinant FVIII was administered on 3 separate weeks following a washout period of at least 72 hours. RESULTS A total of 19 participants were randomized and completed the study. FVIII recovery was lower at 30 minutes post-rFVIII infusion in LBM vs TBW and IBW vs TBW-based dosing, mean difference -0.38 (95% CI: -0.56, -0.20) and -0.28 (95% CI: -0.47, -0.10) IU/dL per IU/kg, respectively. In LBM vs TBW and IBW vs TBW-based dosing, there was a non-significant increase in the proportion of participants with a targeted FVIII recovery of 2.00 ± 0.20 IU/dl per IU/kg, OR = 1.93 (95% CI: 0.44, 8.55) and OR = 3.65 (0.80, 16.72), respectively. DISCUSSION Based on our study's findings, overweight and obese patients with haemophilia A may benefit from an individualized PK analysis using LBM and IBW to determine the most accurate, and potentially cost-effective, method of achieving targeted FVIII recovery.

Abstract

BACKGROUND Dosing of replacement therapy with factor VIII concentrate in patients with haemophilia A in the perioperative setting is challenging. Underdosing and overdosing of factor VIII concentrate should be avoided to minimise risk of perioperative bleeding and treatment costs. We hypothesised that dosing of factor VIII concentrate on the basis of a patient's pharmacokinetic profile instead of bodyweight, which is standard treatment, would reduce factor VIII consumption and improve the accuracy of attained factor VIII levels. METHODS In this open-label, multicentre, randomised, controlled trial (OPTI-CLOT), patients were recruited from nine centres in Rotterdam, Groningen, Utrecht, Nijmegen, The Hague, Leiden, Amsterdam, Eindhoven, and Maastricht in The Netherlands. Eligible patients were aged 12 years or older with severe or moderate haemophilia A (severe haemophilia was defined as factor VIII concentrations of <0·01 IU/mL, and moderate haemophilia as 0·01-0·05 IU/mL), without factor VIII inhibitors, and planned for elective low or medium risk surgery as defined by surgical risk score. Patients were randomly assigned (1:1) using a web-based randomisation system and treatment minimisation, stratified by method of administration of factor VIII concentrate (continuous infusion vs bolus administration) and risk level of surgery (low and medium risk surgery), to the pharmacokinetic-guided or standard treatment group. The primary endpoint was total amount of infused factor VIII concentrate (IU per kg bodyweight) during perioperative period (from day of surgery up to 14 days after surgery). Analysis was by intention to treat and the safety analysis population comprised all participants who underwent surgery with factor VIII concentrate. This study is registered with the Netherlands Trial Registry, NL3955, and is now closed to accrual. FINDINGS Between May 1, 2014, and March 1, 2020, 98 patients were assessed for eligibility and 66 were enrolled in the trial and randomly assigned to the pharmacokinetic-guided treatment group (34 [52%]) or the standard treatment group (32 [48%]). Median age was 49·1 years (IQR 35·0 to 62·1) and all participants were male. No difference was seen in consumption of factor VIII concentrate during the perioperative period between groups (mean consumption of 365 IU/kg [SD 202] in pharmacokinetic-guided treatment group vs 379 IU/kg [202] in standard treatment group; adjusted difference -6 IU/kg [95% CI -88 to 100]). Postoperative bleeding occurred in six (18%) of 34 patients in the pharmacokinetic-guided treatment group and three (9%) of 32 in the standard treatment group. One grade 4 postoperative bleeding event occurred, which was in one (3%) patient in the standard treatment group. No treatment-related deaths occurred. INTERPRETATION Although perioperative pharmacokinetic-guided dosing is safe, it leads to similar perioperative factor VIII consumption when compared with standard treatment. However, pharmacokinetic-guided dosing showed an improvement in obtaining factor VIII concentrations within the desired perioperative factor VIII range. These findings provide support to further investigation of pharmacokinetic-guided dosing in perioperative haemophilia care. FUNDING Dutch Research Council (NWO)-ZonMw and Takeda.

Abstract

Von Willebrand disease (VWD) is the most common inherited bleeding disorder. The management of patients with VWD undergoing surgeries is crucial to prevent bleeding complications. To systematically summarize the evidence on the management of patients with VWD undergoing major and minor surgeries to support the development of practice guidelines. We searched Medline and EMBASE through October 2019 for randomized clinical trials (RCTs), comparative observational studies and case series comparing maintaining factor VIII levels or VWF levels >0.50 IU/mL for at least 3 days in patients undergoing major surgery, and options for perioperative management of patients undergoing minor surgery. Two authors screened, abstracted data, and assessed the risk of bias. We conducted meta-analysis when possible. We evaluated the certainty of the evidence using the GRADE approach. We included 7 case series for major surgeries and 2 RCTs and 12 case series for minor surgeries. Very low certainty evidence showed that maintaining factor VIII levels, or VWF levels > 0.50 IU/mL for at least 3 consecutive days showed excellent hemostatic efficacy (as labeled by the researchers) after 74-100% of major surgeries. Low to very low certainty evidence showed that prescribing tranexamic acid and increasing VWF levels to 0.50 IU/mL resulted in less bleeding complications after minor procedures compared to increasing VWF levels to 0.50 IU/mL alone. Given the low-quality evidence to guide management decisions, a shared-decision model leading to individualized therapy plans will be important in patients with VWD undergoing surgical and invasive procedures.

Abstract

Objectives: In hemophilia A the presence of non-neutralizing antibodies (NNAs) against Factor VIII (FVIII) may predict the development of neutralizing antibodies (inhibitors) and accelerate the clearance of administrated FVIII concentrates. This systematic review aimed to assess: (1) the prevalence and incidence of NNAs in patients with congenital hemophilia without inhibitors and (2) the association between NNAs and patient and treatment characteristics. Methods: We conducted a search in MEDLINE, Embase, Web of Science and the Cochrane database. We included cross-sectional and longitudinal studies reporting on NNAs in patients with hemophilia A and B, who were inhibitor-negative at the start of the observation period. Data were extracted on: hemophilia type and severity, patient and treatment characteristics, NNA prevalence and incidence, NNA assays and inhibitor development. Two independent reviewers performed study selection, data extraction and risk of bias assessment, using adapted criteria of the Joanna Briggs Institute. Studies were classified as high-quality when ≥5/9 criteria were met. NNA assays were classified as high-quality when both quality criteria were met: (1) use of positive controls and (2) competition with FVIII to establish FVIII-specificity. We reported NNA prevalence and incidence for each study. The pooled NNA prevalence was assessed for well-designed studies in previously treated patients, employing high-quality NNA assays. Results: We included data from 2,723 inhibitor-negative patients with hemophilia A, derived from 28 studies. Most studies were cross-sectional (19/28) and none reported on NNAs in hemophilia B. Study design was of high quality in 16/28 studies and the NNA assay quality was high in 9/28 studies. Various NNA assays were used, predominantly ELISA (18/28) with different cut-off values. We found a large variety in NNA prevalence (Range, 0-100%). The pooled NNA prevalence in high-quality studies was 25% (95% CI, 16-38%). The incidence of new NNA development was reported in one study (0.01 NNA per person-exposure day). Conclusion: This systematic review identified studies that were heterogeneous in study design, patient population and NNA assay type, with NNA prevalence ranging from 0 to 100% in inhibitor-negative patients with hemophilia A. The pooled NNA prevalence was 25% in high-quality studies including only previously treated patients and performing high-quality NNA assays.