Pharmacokinetics and pharmacodynamics of an oral formulation of decitabine and tetrahydrouridine.

BACKGROUND: Sickle cell disease (SCD) is caused by an inherited structural abnormality of adult hemoglobin causing polymerization. Fetal hemoglobin interferes with polymerization but is epigenetically silenced by DNA methyltransferase 1 (DNMT1) in adult erythropoiesis. Decitabine depletes DNMT1 and increases fetal and total hemoglobin in SCD patients, but is rapidly catabolized by cytidine deaminase (CDA) in vivo. Tetrahydrouridine (THU) inhibits CDA, safeguarding decitabine. METHODS: The pharmacokinetics and pharmacodynamics of three oral combination formulations of THU and decitabine, with different coatings producing different delays in decitabine release, were investigated in healthy participants. RESULTS: Tetrahydrouridine and decitabine were rapidly absorbed into the systemic circulation after a single combination oral dose, with relative bioavailability of decitabine ≥74% in fasted males compared with separate oral administration of THU followed by decitabine 1 h later. THU and decitabine Cmax and area under the plasma concentration versus time curve were higher in females versus males, and fasted versus fed states. Despite sex and food effect on pharmacokinetics, the pharmacodynamic effect of DNMT1 downregulation was comparable in males and females and fasted and fed states. Treatments were well tolerated. CONCLUSION: Combination oral formulations of THU with decitabine produced pharmacokinetics and pharmacodynamics suitable for oral DNMT1-targeted therapy.

Measuring factor VIII activity in samples from patients treated with N8-GP (Esperoct® ; turoctocog alfa pegol) during the pathfinder clinical trials programme.

FVIII activity in samples taken at various time points from 21 patients treated with N8-GP (Esperoct® ; turoctocog alfa pegol) during the pathfinder clinical trial programme was assessed and compared using different assay methods. FVIII activity measurements in samples from patients treated with N8-GP were similar using chromogenic assays, regardless of calibration method or kit/analyser combination. FVIII activity measurements using one-stage aPTT-based assays were slightly lower when calibrated using normal human plasma (NHP) compared with a product-specific standard; this difference may be partially attributable to differences in the aPTT reagent/analyser combinations used to perform the measurements. Overall, these results confirm the accuracy of FVIII activity measurements using N8-GP-treated patient samples and routine clinical laboratory methods with NHP calibration.

Evaluation of N8-GP Activity Using a One-Stage Clotting Assay: A Single-Center Experience.

N8-GP (ESPEROCT®; turoctocog alfa pegol; Novo Nordisk A/S, Bagsvaerd, Denmark) is an extended half-life recombinant factor VIII (FVIII) molecule. FVIII-deficient plasma spiked with N8-GP can be accurately measured using many activated partial thromboplastin time (aPTT)-based one-stage clotting assay reagents with normal human plasma calibrators. To date, there are few data on the measurement accuracy of samples from patients treated with N8-GP. Here, we measure patient samples during routine treatment monitoring. Three previously treated patients with severe hemophilia A (HA) without inhibitors (baseline FVIII activity <0.01 IU/mL) received 50 IU/kg N8-GP every fourth day or twice weekly over 5 years as part of the pathfinder2 trial. Patient samples were monitored using the Pathromtin® SL aPTT reagent (Siemens Healthcare GmbH, Erlangen, Germany), a BCS® XP System analyzer (Siemens), and Standard Human Plasma (Siemens) or product-specific calibrators. Patient age ranged from 36 to 62 years. Overall, measurements performed using product-specific or Standard Human Plasma calibrators were in good agreement, with ratios randomly distributed around 1.0. Peak ratios tended to be closer to 1.0 than trough samples. Pathromtin® SL with Standard Human Plasma calibrator consistently and accurately measured FVIII activity in samples from severe HA patients receiving N8-GP prophylaxis.

A field study evaluating the activity of N8-GP in spiked plasma samples at clinical haemostasis laboratories.

AIM: N8-GP (turoctocog alfa pegol) is a glycoPEGylated, extended half-life human recombinant factor VIII (FVIII) shown to be an efficacious treatment for patients with haemophilia A. Accurate monitoring of replacement therapy helps ensure proper dosing, leading to better patient care. The objective of this field study was to evaluate the accuracy and intra- and inter-laboratory variabilities of N8-GP and rAHF (Advate® ) FVIII activity (FVIII:C) measurements in clinical laboratories using their routine methods and reagents. METHODS: Laboratories measured plasma samples spiked with 0.03, 0.2, 0.6 and 0.9 IU/mL N8-GP or rAHF. Samples were blinded, and laboratories were instructed to perform evaluations using their routine FVIII activity assays and calibrators. RESULTS: Of the 67 participating laboratories from 25 countries, 60 used a one-stage assay, 36 used a chromogenic assay, and 29 used both one-stage and chromogenic assays. Participating laboratories used nine different activated partial thromboplastin time (aPTT) reagents, the most common being SynthASil® and Actin® FS. Most aPTT reagents recovered N8-GP close to target. Three silica-based aPTT reagents (APTT-SP, TriniCLOT™ and STA® PTT-Automate) underestimated N8-GP, recovering 40%-83% of target concentration. For chromogenic assays, N8-GP and rAHF recoveries were comparable at all concentrations, with overall mean recoveries for both products close to 130%. Assay variability was similar for both assay types and both products; inter-laboratory variability was greater than intra-laboratory variability and highest at 0.03 IU/mL. CONCLUSIONS: Most clinical laboratories accurately measured N8-GP and rAHF when using their in-house one-stage or chromogenic FVIII:C assays. However, three silica-based aPTT reagents underestimated N8-GP recovery.

Once-weekly prophylaxis with 40 IU/kg nonacog beta pegol (N9-GP) achieves trough levels of >15% in patients with haemophilia B: Pooled data from the paradigm™ trials.

INTRODUCTION: Prophylaxis with replacement factor IX (FIX) reduces bleeding frequency and improves quality of life in haemophilia B patients. With prophylaxis, the likelihood of bleeding is lowered with increasing trough levels. New products with extended half-life (EHL) can maintain high factor activity levels over prolonged periods, compared with standard FIX products. AIM: To evaluate the safety, efficacy and pharmacokinetics of the new recombinant FIX EHL product, nonacog beta pegol (N9-GP), using pooled data, with a focus on-but not limited to-prophylaxis at 40 IU/kg. METHODS: N9-GP has been investigated in males with congenital haemophilia B and FIX activity ≤2% in the paradigm™ clinical trial programme. This analysis includes pooled data from five completed paradigm™ trials conducted in previously treated adults, adolescents and children, focusing on results of prophylaxis with 40 IU/kg once-weekly intravenous dosing. RESULTS: In total, 115 previously treated patients were exposed to N9-GP. Of 54 patients (47%) treated with N9-GP 40 IU/kg once-weekly prophylaxis, 72% experienced no spontaneous bleeds over 1 year. In all patients receiving 40 IU/kg once-weekly, median overall annualized bleeding rate (ABR) was 1.03 (interquartile range 0.00; 2.89); median spontaneous ABR was 0.00 (0.00; 0.80). No patients developed inhibitors. Estimated mean steady-state trough levels with N9-GP 40 IU/kg once-weekly were ≥15% overall; 27.3% in adolescents and adults. CONCLUSION: N9-GP 40 IU/kg once-weekly was well tolerated and effective in preventing bleeding, maintaining mean FIX activity levels ≥15% across all age groups. N9-GP may provide a new treatment option for preventing bleeding in haemophilia B patients.

Clinical evaluation of glycoPEGylated recombinant FVIII: Efficacy and safety in severe haemophilia A.

Turoctocog alfa pegol (N8-GP) is a novel glycoPEGylated extended half-life recombinant factor VIII (FVIII) product developed for prophylaxis and treatment of bleeds in patients with haemophilia A, to enable higher activity levels with less frequent injections compared with standard FVIII products. This phase III (NCT01480180), multinational, open-label, non-randomised trial evaluated the safety and clinical efficacy of N8-GP when administered for treatment of bleeds and for prophylaxis, in previously treated patients aged ≥12 years with severe haemophilia A. Patients were allocated to receive N8-GP for prophylaxis or on-demand treatment for up to 1.8 years. Patients on prophylaxis were administered one dose of 50 IU/kg of N8-GP every fourth day. Bleeds were treated with doses of 20-75 IU/kg. Total exposure to N8-GP in the trial was 14,114 exposure days (159 patient-years). For the prophylaxis arm (n=175), the median annualised bleeding rate (ABR) was 1.33 (interquartile range, 0.00-4.61), the mean ABR was 3.70 (95 % confidence interval 2.94-4.66) and 70 (40 %) patients had no bleeds during the trial. Across treatment arms, 83.6 % of bleeds resolved with one injection and 95.5 % with up to two injections. N8-GP had a favourable safety profile and was well tolerated. The frequency and types of adverse events reported were as expected in this population. One patient developed inhibitory antibodies against FVIII (≥0.6 Bethesda units [BU]) after 93 N8-GP exposure days. No clinically significant safety concerns were identified and N8-GP was effective for prophylaxis and treatment of bleeds in previously treated patients.