AIM: These post hoc analyses investigated the bleeding patterns in target joints.

METHODS: Patients randomized to 40 or 10 IU kg(-1) once weekly prophylaxis who had at least one target joint were included. Baseline demographics and disease-specific data were collected. Bleeding patterns were assessed, and an International Society on Thrombosis and Haemostasis (ISTH) definition of target joints was used.

RESULTS: A total of 67% and 8% of patients in the 40 and 10 IU kg(-1) arm, respectively, did not experience target joint bleeds during the paradigm(™) 2 trial. Twenty-four target joints were recorded in each prophylaxis arm at baseline. During the paradigm(™) 2 trial, no bleeds were reported in 17 (71%) and 7 (29%) target joints in the 40 and 10 IU kg(-1) arms respectively. All target joint bleeds in the 40 IU kg(-1) once weekly prophylaxis arm were controlled with a single injection of 40 IU kg(-1) nonacog beta pegol. By the latest ISTH definition, 90% and 58% of target joints in the 40 and 10 IU kg(-1) arms, respectively, were no longer considered target joints at the end of the paradigm(™) 2 trial. At the end of the paradigm(™) 4 extension trial, all target joints in the 40 IU kg(-1) arm were no longer considered target joints.

AIM: The aim of this study was to evaluate the pharmacokinetics (PK) of N9-GP.

METHODS: Data from 41 previously treated haemophilia B patients, enrolled globally (16 adolescents/adults and 25 children; FIX activity ≤0.02 IU mL-1) with no history of FIX inhibitors, were included. N9-GP was administered once-weekly as 10 IU kg-1or 40 IU kg-1in adolescents/adults and 40 IU kg-1in children. Blood was sampled up to 168 h (1 week) post dose. Standard PK was estimated on the basis of plasma FIX activity vs. time (PK profiles) using non-compartmental methods. Furthermore, a population PK analysis and FIX activity predictions were performed.

RESULTS: Incremental recoveries were 0.02 (IU mL-1)/(IU kg-1) in both adolescents/adults and children. The extended half-life resulted in mean trough levels of 0.27 IU mL-1for adolescents/adults and 0.17 IU mL-1for children at steady-state after weekly dosing at 40 IU kg-1. The population PK analysis confirmed a mono-exponential decay in FIX activity and allowed for predictions of FIX activity for adolescents/adults above 0.15 IU mL-1at all times and 6.4 days week-1in children.

METHODS: Patients chose to continue treatment with nonacog beta pegol in either one of two once-weekly prophylaxis arms (10IU/kg or 40IU/kg), or an on-demand arm (40IU/kg for mild/moderate bleeds; 80IU/kg for severe bleeds). The primary objective was to evaluate immunogenicity; key secondary objectives included assessing safety and haemostatic efficacy in the treatment and prevention of bleeds.

RESULTS: Seventy-one patients received prophylaxis or on-demand treatment. No patient developed an inhibitor and no safety concerns were identified. The success rate for the treatment of reported bleeds was 94.6%; most (87.9%) resolved with one injection. The median annualised bleeding rate for patients on prophylaxis was 1.36 (interquartile range [IQR] 0.00-2.23) and 1.00 (IQR 0.00-2.03) for the 10 and 40IU/kg treatment arms, respectively. The mean FIX activity trough achieved for 10 and 40IU once weekly was 9.8% and 21.3%, respectively. Fourteen patients on prophylaxis underwent 23 minor surgical procedures; haemostatic perioperative outcomes for all of those evaluated were 'excellent' or 'good'.

METHODS: This prospective, multicentre, open-label, randomised, phase 3a trial (explorer8) was conducted at 69 investigational sites in 31 countries. Eligible patients were male, aged 12 years or older, and had congenital severe haemophilia A or moderate or severe haemophilia B without inhibitors and with documented treatment with clotting factor concentrate in the 24 weeks before screening. The trial was paused because of non-fatal thromboembolic events in three patients (two from this trial [explorer8] and one from a related trial in haemophilia with inhibitors [explorer7; NCT04083781]) and restarted with mitigation measures, including a revised dosing regimen of subcutaneous concizumab at 1·0 mg/kg loading dose on day 1 and subsequent daily doses of 0·20 mg/kg from day 2, with options to decrease to 0·15 mg/kg, stay on 0·20 mg/kg, or increase to 0·25 mg/kg on the basis of concizumab plasma concentration measured after 4 weeks on concizumab. Patients recruited after treatment restart were randomly assigned 1:2 using an interactive web response system to receive no prophylaxis and continue on-demand clotting factor (group 1) or concizumab prophylaxis (group 2). The primary endpoints were the number of treated spontaneous and traumatic bleeding episodes for patients with haemophilia A and haemophilia B separately, assessed at the confirmatory analysis cutoff in randomly assigned patients. Analyses were by intention-to-treat. There were two additional groups containing non-randomly-assigned patients: group 3 contained patients who entered the trial before the trial pause and were receiving concizumab in the phase 2 trial (explorer5; NCT03196297), and group 4 contained patients who received previous clotting factor concentrate prophylaxis or on-demand treatment in the non-interventional trial (explorer6; NCT03741881), patients randomly assigned to groups 1 or 2 before the treatment pause, and patients from explorer5 enrolled after the treatment pause. The safety analysis set contained all patients who received concizumab. Superiority of concizumab over no prophylaxis was established if the two-sided 95% CI of the treatment ratio was less than 1 for haemophilia A and for haemophilia B. This trial is registered with ClinicalTrials.gov, NCT04082429, and its extension part is ongoing.

FINDINGS: Patients were recruited between Nov 13, 2019 and Nov 30, 2021; the cutoff date for the analyses presented was July 12, 2022. 173 patients were screened, of whom 148 (86%) were randomly assigned or allocated to the four groups in the study after trial restart on Sept 30, 2020 (nine with haemophilia A and 12 with haemophilia B in group 1; 18 with haemophilia A and 24 with haemophilia B in group 2; nine with haemophilia A in group 3; and 46 with haemophilia A and 30 with haemophilia B in group 4). The estimated mean annualised bleeding rate ratio for treated spontaneous and traumatic bleeding episodes during concizumab prophylaxis versus no prophylaxis was 0·14 (95% CI 0·07-0·29; p<0·0001) for patients with haemophilia A and 0·21 (0·10-0·45; p<0·0001) for patients with haemophilia B. The most frequent adverse events in patients who received concizumab were SARS-CoV-2 infection (19 [13%] of 151 patients), an increase in fibrin D-dimers (12 [8%] patients), and upper respiratory tract infection (ten [7%] patients). There was one fatal adverse event possibly related to treatment (intra-abdominal haemorrhage in a patient from group 4 with haemophilia A with a long-standing history of hypertension). No thromboembolic events were reported between the trial restart and confirmatory analysis cutoff.

INTERPRETATION: Concizumab was effective in reducing the bleeding rate compared with no prophylaxis and was considered safe in patients with haemophilia A or B without inhibitors. The results of this trial suggest that concizumab has the potential to be one of the first subcutaneous treatment options for patients with haemophilia B without inhibitors.