Search

The classical goals of haemophilia A treatment are to prevent bleeds, minimise the risk of long-term complications associated with joint damage, and improve quality of life by maintaining appropriate factor VIII [FVIII] levels. The dose and frequency of FVIII replacement therapies required to reduce bleeds is now known to vary amongst individuals, and may change for the same individual over time, meaning that a standardised dose and regimen may not provide optimal protection to all patients. Here we review the evolving treatment landscape for haemophilia A, and discuss how an increased understanding of the pharmacology and pharmacokinetics underlying FVIII replacement and non-factor replacement therapies could improve patient outcomes. We also review the strengths and weaknesses of current treatments and explore the benefits of personalised therapy and review how this may best be achieved with current treatment options. The key points of our review are summarised in the accompanying short video.

Pharmacokinetic-based prophylaxis of replacement factor VIII products has been encouraged in the past years, but the exposure (factor VIII activity)-response (bleeding frequency) relationship remains unclear. The aim of this study was to characterize the relationship between factor VIII dose, plasma factor VIII activity, bleeding patterns and individual characteristics in severe hemophilia A patients. Pooled pharmacokinetic and bleeding data during prophylactic treatment with BAY 81-8973 (octocog alfa) were obtained from the three LEOPOLD trials. The population pharmacokinetics of factor VIII activity and longitudinal bleeding frequency, as well as bleeding severity, were described using nonlinear mixed effects modelling in NONMEM. In total, 183 patients (median age 22 years [range, 1-61]; weight 60 kg [11-124]) contributed with 1535 plasma factor VIII activity observations, 633 bleeds and 11 patient/study characteristics (median observation period 12 months [3.1-13.1]). A parametric repeated time-to-categorical bleed model, guided by plasma factor VIII activity from a 2-compartment population pharmacokinetic model, described the time to the occurrence of bleeds and their severity. Bleeding probability decreased with time of study, and a bleed was not found to affect the time of the next bleed. Several covariate effects were identified, including the bleeding history in the 12-month pre-study period increasing the bleeding hazard. However, unexplained inter-patient variability for the phenotypic bleeding pattern remained large (111%CV). Further studies to translate the model into a tool for dose individualization that considers the individual bleeding risk are required. Research based on a post-hoc analysis of the LEOPOLD studies (ClinicalTrials.gov identifiers NCT01029340, NCT01233258 and NCT01311648).

Objectives: To report interim data from TAURUS, a study assessing real-world prophylactic treatment with unmodified, full-length recombinant FVIII BAY 81-8973 (Kovaltry®; Bayer) indicated for haemophilia A. Methods: TAURUS (NCT02830477) is an international, open-label, prospective, non-interventional, single-arm study with a one-year observation period (target N = 350). Patients have moderate or severe haemophilia A (FVIII ≤5% or ≤1%) and ≥50 exposure days to any FVIII product. Clinician- and patient-reported outcomes are captured on previous product use, changes in prophylaxis dose and dosing frequency, FVIII consumption, reported bleeding rates, treatment satisfaction and adherence, pharmacokinetic (PK) data (if available) and safety data. Results: At cut-off, baseline data were available from 160 patients (89 had ≥6 months of follow-up data). Most patients had severe haemophilia A (85%), infused BAY 81-8973 ≥ 3×/wk (59%) and experienced a median number of total bleeds of 2.0 (non-annualised; 246 days median documentation period). Good levels of treatment satisfaction (Hemo-SATA,P) and adherence (VERITAS-Pro) were maintained. TAURUS demonstrated a favourable PK profile of BAY 81-8973 in comparison with other standard half-life rFVIIIs and supported the WAPPS PopPK model. No patients developed inhibitors. Conclusions: TAURUS data demonstrate effective prophylaxis with BAY 81-8973 in the real world without compromising patient satisfaction or adherence., SCOPUS: ar.j, DecretOANoAutActif, info:eu-repo/semantics/published

Bayesian forecasting for dose individualization of prophylactic factor VIII replacement therapy using pharmacokinetic samples is challenged by large interindividual variability in the bleeding risk. A pharmacokinetic‐repeated time‐to‐event model‐based forecasting approach was developed to contrast the ability to predict the future occurrence of bleeds based on individual (i) pharmacokinetic, (ii) bleeding, and (iii) pharmacokinetic, bleeding and covariate information using observed data from the Long‐Term Efficacy Open‐Label Program in Severe Hemophilia A Disease (LEOPOLD) clinical trials (172 severe hemophilia A patients taking prophylactic treatment). The predictive performance assessed by the area under receiver operating characteristic (ROC) curves was 0.67 (95% confidence interval (CI), 0.65–0.69), 0.78 (95% CI, 0.76–0.80), and 0.79 (95% CI, 0.77–0.81) for patients ≥ 12 years when using pharmacokinetics, bleeds, and all data, respectively, suggesting that individual bleed information adds value to the optimization of prophylactic dosing regimens in severe hemophilia A. Further steps to optimize the proposed tool for factor VIII dose adaptation in the clinic are required.