A Research Study Investigating Nonacog Beta Pegol (N9-GP) for Treatment and Prevention of Bleedings in Chinese People With Haemophilia B

Haemostatic effect of N9-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.

Number of bleeding episodes per year data is reported. Annualised bleeding rate (ABR) is the number of bleeding episodes per year.

The mean number of injections of N9-GP used for treatment of a bleed from start to stop of a bleed was reported and it was measured in international units per kilogram per bleed (IU/kg/bleed).

The mean consumption of N9-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 participants who received prophylaxis treatment. Chromogenic assay was performed with N9-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 participants as a random effect. The mean trough is presented back-transformed to the natural scale. The estimated mean/average steady state trough level of FVIII over time (all visits from start of treatment (week 0) until end of treatment) was presented. Data is reported for specific treatment in which participants were a part of at any time from week 0 to end of the treatment (EOT) Week 50, not at specific time points assessed from week 0 to EOT.

Number of participants who developed inhibitory antibodies (IA) 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 N9-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 international units per kilogram (IU/kg) body weight. FVIII activity was measured with a chromogenic assay.

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.

Area under the plasma activity versus time profile from time zero to 168 hours (AUC0-168h) was measured.