Efficacy and Safety of Turoctocog Alfa Pegol (N8-GP) for Prophylaxis and Treatment of Bleeding Episodes in Previously Treated Chinese Patients With Haemophilia A (pathfinder10)

Haemostatic effect of N8-GP for treatment of bleeding episodes was assessed by 4-point response scale: none, moderate, good or excellent. Evaluation during trial was done by participant and/or parent(s)/caregiver within approximately 8 hours after a single injection as follows: Excellent: Abrupt pain relief and/or clear improvement in objective signs of bleeding within approximately 8 hrs after a single injection; Good: Definite pain relief and/or improvement in signs of bleeding within approximately 8 hrs after a single injection, but possibly requiring more than one injection for complete resolution; Moderate: Probable or slight beneficial effect within approximately 8 hours after the first injection, but usually requiring more than one injection; None: No improvement, or worsening of symptoms.

The mean number of injections of N8-GP used for treatment of a bleed from start to stop of a bleed was reported.

The mean consumption of N8-GP for prophylaxis per year per participant was reported and it was measured in international units per kilogram per year (IU/kg/year).

Trough levels of FVIII was reported for all participnats who received prophylaxis treatment. Chromogenic assay was performed with N8-GP product specific standard (PSS) as a calibrator. The analysis is based on a mixed model on the log transformed plasma FVIII activity with age group as fixed effect and participant as a random effect. The mean trough is presented back-transformed to the natural scale.

Percentage of participants who developed inhibitory antibodies against FVIII was presented. A participant was said to have FVIII-inhibitors if two consecutive tests, preferably within 2 weeks, were positive (greater than or equal to (≥) 0.6 bethesda unit (BU)). For the calculation of the inhibitor rate the numerator was included for all participants with neutralising antibodies while the denominator was included for all participants with a minimum of 50 exposures plus any participants with less than 50 exposures but with neutralising inhibitor.

An adverse event (AE) was defined as any unfavorable and unintended sign (including an abnormal laboratory finding), symptom or disease temporally associated with the use of a product, whether or not considered related to the product. All presented AEs are treatment-emergent. A treatment-emergent adverse event was defined as an event with onset after first N8-GP administration.

A serious adverse event (SAE) is defined as any untoward medical occurrence that at any dose results in death, or is life-threatening, or requires inpatient hospitalization or causes prolongation of existing hospitalization results in persistent or significant disability/incapacity, or may have caused a congenital anomaly/birth defect, or requires intervention to prevent permanent impairment or damage. All presented SAEs are treatment-emergent (any serious adverse events which occurred after trial product administration).

The incremental recovery was calculated by subtracting the FVIII activity (IU/mL) measured in plasma at time 0 from that measured at time 30 min after dosing and dividing this difference by the dose injected at time 0 expressed as IU/kg body weight. FVIII activity was measured with a chromogenic assay.

FVIII plasma activity was measured after 30 mins of injection. FVIII activity was measured with a chromogenic assay.

FVIII plasma activity was measured after 96 h of injection. This was measured at two time points Week 0 and Week 28 during the study. Chromogenic assay was performed.

Area under the plasma activity versus time profile from time zero to infinity (AUC0-inf) was measured.

Area under the plasma activity versus time profile from time zero to last measurable activity (AUC0-t) was measured.

Area under the plasma activity versus time profile from time zero to 96 hours (AUC0-96h) was measured.

Accumulation ratio was calculated as AUC(0-96h) at steady state/AUC(0-96h) at single dose. AUC(0-96) is the area under the plasma activity versus time profile from time zero to 96 hours.

Terminal half life was calculated as ln(2)/λz; where λz is the terminal elimination rate constant. The terminal elimination rate constant was estimated using linear regression on the terminal part of the log (activity) versus time profile.

Clearance (CL) of drug after intravenous administration was reported. Clearance was calculated using the formula CL= Dose / AUC(0-inf) for single dose and CL= Dose / AUC(0-96) h for steady state.

Apparent volume of distribution (Vz) based on the terminal phase was measured. Apparent volume of distribution was calculated using formula: total plasma clearance divided by terminal elimination rate constant (Vz= CL/λz).

Apparent volume of distribution (Vss) at steady-state was measured. Apparent volume of distribution (Vss) was calculated using formula: total plasma clearance multiplied by mean residence time (Vss=CL*MRT).

Percentage of AUC(0-inf) determined by extrapolation. It was calulating using formula: Area under the plasma activity versus time profile from given measurable time to infinity (AUCt-inf)/Area under the plasma activity versus time profile from time zero to infinity (AUC0-inf).

Mean residence time (MRT) calculated as area under the first moment plasma concentration-time curve (AUMC [0-inf]) divided by AUC (0-inf). (AUMC [0-inf]) is the area under the first moment plasma concentration-time curve from time 0 to infinity.

The terminal elimination rate constant was estimated using linear regression on the terminal part of the log(activity) versus time profile.