Factor VIII activity of BAY 94-9027 is accurately measured with most commonly used assays: Results from an international laboratory study.

INTRODUCTION: Discrepancies in the measurement of modified factor VIII (FVIII) products have been recognized, highlighting the need for adjustments in clinical laboratory practices to ensure effective monitoring of patients treated with these products, particularly using the one-stage (activated partial thromboplastin time [aPTT]) assay. AIM: To assess the ability of clinical laboratories to measure the activity of BAY 94-9027, a PEGylated extended half-life FVIII product, using routine (predominantly one-stage) assays in clinical laboratories METHODS: Blinded samples of FVIII-deficient plasma spiked with defined levels of BAY 94-9027 and a recombinant FVIII product comparator were provided to 52 clinical laboratories that routinely conduct FVIII testing. Samples were provided at 3 concentrations (low, medium and high), and laboratories analysed the samples using routine in-house one-stage and, when available, chromogenic assays. Acceptable spiked recovery (accuracy) of the local laboratory methods to measure BAY 94-9027 was the primary endpoint of the study. RESULTS: Accurate FVIII measurements were obtained at all concentrations for both products using the chromogenic assay and most of the commonly used one-stage reagents, both ellagic acid and silica based. Two specific silica-based reagents, APTT-SP and PTT-A, underestimated BAY 94-9027 levels at all concentrations, consistent with previous findings. CONCLUSIONS: FVIII activity of BAY 94-9027 was accurately measured with most commonly used one-stage assays used in routine clinical practice. The chromogenic assay was also accurate. It is recommended that clinical laboratories identify and avoid specific inappropriate reagents, such as the APTT-SP and PTT-A, in their one-stage assays for FVIII monitoring.

BAY 94-9027, a PEGylated recombinant factor VIII, exhibits a prolonged half-life and higher area under the curve in patients with severe haemophilia A: Comprehensive pharmacokinetic assessment from clinical studies.

INTRODUCTION: Recombinant factor VIII (rFVIII) products with extended half-lives, such as BAY 94-9027, can potentially maintain higher FVIII levels for longer periods of time, thus providing improved bleeding protection vs standard-acting FVIII products. AIM: To characterize the pharmacokinetic (PK) profile of BAY 94-9027 from phase 1, phase 2/3 (PROTECT VIII) and phase 3 (PROTECT VIII Kids) clinical trials in adults, adolescents and children with severe haemophilia A METHODS: Patients with severe haemophilia A (FVIII <1%) with >50 FVIII exposure days (EDs) and no history of inhibitors were included in the phase 1 (18-65 years, ≥150 EDs), PROTECT VIII (12-65 years, ≥150 EDs) and PROTECT VIII Kids (<12 years, >50 EDs) trials. PK parameters were assessed following a 25-IU/kg or 60-IU/kg BAY 94-9027 dose in the phase 1 study after the first and repeated infusion, in PROTECT VIII after the first and repeated 60-IU/kg infusion and in PROTECT VIII Kids after a single 60-IU/kg infusion. The chromogenic assay was used to assess FVIII activity. RESULTS: Compared with sucrose-formulated rFVIII, BAY 94-9027 had reduced clearance that resulted in a ~1.4-fold increase in half-life and dose-normalized area under the curve (AUC). The BAY 94-9027 PK profile was comparable after single- and repeated-dose administrations. Dose-proportional increases were observed between 25- and 60-IU/kg administrations. BAY 94-9027 PK characteristics were age dependent, consistent with other FVIII products. CONCLUSIONS: BAY 94-9027 shows an extended half-life and increased AUC vs standard-acting FVIII products. These PK characteristics will result in higher FVIII levels for longer duration.

BAY 81-8973 safety and efficacy for prophylaxis and treatment of bleeds in previously treated children with severe haemophilia A: results of the LEOPOLD Kids Trial.

INTRODUCTION: BAY 81-8973, a full-length, unmodified, recombinant factor VIII (FVIII) in development for treatment of haemophilia A, has the same primary amino acid sequence as Bayer's sucrose-formulated recombinant FVIII but is produced with more advanced manufacturing technologies. AIM: To demonstrate safety and efficacy of BAY 81-8973 for prophylaxis and treatment of bleeds in previously treated children. METHODS: In this phase III, multicentre, open-label, nonrandomized study, boys aged ≤12 years with severe haemophilia A and ≥50 exposure days (EDs) to FVIII products received prophylaxis with BAY 81-8973 25-50 IU kg(-1) ≥2 times weekly for ≥50 EDs. The efficacy endpoint was annualized number of total bleeds. Adverse events (AEs) and immunogenicity were assessed. RESULTS: Fifty-one patients were treated (age: <6 years, n = 25; 6-<12 years, n = 26) with a 2× per week (43%) or >2× per week (57%) regimen at study start. Median [quartile 1; quartile 3 (Q1; Q3)] annualized number of bleeds for the combined age groups was 1.90 (0; 6.02) for total bleeds, 0 (0; 2.01) for joint bleeds and 0 (0; 0) for spontaneous bleeds. Median (Q1; Q3) annualized number of total bleeds within 48 h of previous prophylaxis infusion was 1.88 (0; 3.97) for children aged <6 years and 0 (0; 1.96) for children aged 6-<12 years. No drug-related serious AEs or inhibitors were reported. CONCLUSIONS: Prophylaxis with BAY 81-8973 using individualized prophylaxis regimens of 2× per week, 3× per week and every-other-day infusions was efficacious in prevention and treatment of bleeds in children with severe haemophilia A. Treatment with BAY 81-8973 was well tolerated.

PEGylated therapeutic proteins for haemophilia treatment: a review for haemophilia caregivers.

PEGylation is the technology involving the covalent attachment of polyethylene glycol (PEG) to a protein-, peptide- or small-molecule drug to improve their pharmacokinetic, pharmacodynamic and immunological profiles, and thus, enhance the therapeutic effect. Today, PEGylation of proteins is a well-established technology and is being used in the treatment of a variety of clinical disorders. Several PEGylated coagulation proteins for haemophilia A and B are under development with the goal of prolonging the circulation half-life of factor VIII (FVIII) or factor IX. The prolongation of half-life, resulting in less frequent injections can provide significant benefits in improving the quality of life of subjects with haemophilia and improvement in adherence to treatment. A review of published literature on PEGylated therapeutic products currently approved for human use and a discussion of a PEGylated recombinant FVIII molecule (BAY 94-9027, Bayer HealthCare, Berkeley, CA, USA) currently being investigated in the pivotal clinical trial prior to registration is provided. Available safety information of PEGylated proteins containing high molecular weight PEG does not indicate any safety concerns to date, following long-term (chronic) use in animal models or patients. Chronic use of currently available PEGylated products has been shown to be safe, paving the way for chronic use of PEGylated coagulation products in persons with haemophilia.

The U.S. Thrombosis and Hemostasis Centers pilot sites program.

Venous thromboembolism (VTE) is a common disorder associated with significant morbidity and mortality. Despite important advances in understanding the etiology of VTE, delivery of care to patients with thrombosis and thrombophilia is frequently incomplete and highly variable. A comprehensive model of health care has been used successfully to treat and prevent complications for people with hemophilia and other chronic disorders. The effectiveness of an integrated healthcare model for patients with all coagulation disorders has yet to be evaluated. The Division of Hereditary Blood Disorders of the Centers for Disease Control and Prevention (CDC) is collaborating with eight Thrombosis and Hemostasis Centers (pilot sites) to provide health-related services and conduct research directed toward the reduction or prevention of complications of thrombosis and thrombophilia. The initial objectives of the collaboration are to (1) determine the efficacy of integrated multidisciplinary care and prevention services for people with hemostatic disorders, (2) assess unmet needs for service delivery and identify outreach strategies to improve access to care, (3) develop effective messages aimed at disease management and prevention, and (4) foster the development of training programs to enhance provider skills for the delivery of patient care. To address these objectives, the investigators and CDC have developed and implemented a web-based patient registry to follow prospectively service allocation and patient outcomes. Funding for the program began in October 2001. All eight funded centers are affiliated with U.S. medical schools. Principal investigators at the centers are hematologists (five adult, two pediatric) or cardiologists. Faculty in obstetrics-gynecology, surgery, and multiple other specialties are integral to the model of care at the centers. Other critical components at the centers are clinical laboratory services, training programs, research networks, and education and outreach programs. From August 2003 to March 2006, over 2,600 patients were enrolled in the registry, accounting for a total of more than 5,000 visits to the centers. Immediate goals of the data collection at the centers are to characterize patients receiving care at centers and document the state of health services provided. Long-term goals are to evaluate prospectively clinical outcomes for patients receiving multidisciplinary care and prevention services at centers. The network of data collection across centers will facilitate future collaborative clinical and epidemiologic investigations and enhance collective expertise in hemostasis and coagulation disorders.