METHODS: This multicentre, randomised, open-label phase 3 study was done at 26 sites (primarily secondary or tertiary centres) in 12 countries. Men, boys, and young adults aged 12 years or older with severe haemophilia A or haemophilia B with inhibitors previously treated with on-demand bypassing agents were randomly assigned (2:1) to receive once-a-month 80 mg subcutaneous fitusiran prophylaxis (fitusiran prophylaxis group) or to continue with bypassing agents on-demand (bypassing agents on-demand group) for 9 months. The primary endpoint was mean annualised bleeding rate during the efficacy period in the intention-to-treat population estimated by negative binomial model. Safety was assessed as a secondary endpoint in the safety population. This trial is complete and is registered with ClinicalTrials.gov, NCT03417102.

FINDINGS: Between Feb 14, 2018, and June 23, 2021, 85 participants were screened for inclusion, of whom 57 (67%; 57 [100%] men; median age 27·0 years [IQR 19·5-33·5]) were randomly assigned: 19 (33%) participants to the bypassing agent on-demand group and 38 (67%) participants to the fitusiran prophylaxis. Negative binomial model-based mean annualised bleeding rate was significantly lower in the fitusiran prophylaxis group (1·7 [95% CI 1·0-2·7]) than in the bypassing agents on-demand group (18·1 [10·6-30·8]), corresponding to a 90·8% (95% CI 80·8-95·6) reduction in annualised bleeding rate in favour of fitusiran prophylaxis (p<0·0001). 25 (66%) participants had zero treated bleeds in the fitusiran prophylaxis group versus one (5%) in the bypassing agents on-demand group. The most frequent treatment-emergent adverse event in the fitusiran prophylaxis group was increased alanine aminotransferase in 13 (32%) of 41 participants in the safety population; there were no increased alanine aminotransferase treatment-emergent adverse events in the bypassing agents on-demand group. Suspected or confirmed thromboembolic events were reported in two (5%) participants in the fitusiran prophylaxis group. No deaths were reported.

INTERPRETATION: Subcutaneous fitusiran prophylaxis resulted in statistically significant reductions in annualised bleeding rate in participants with haemophilia A or haemophilia B with inhibitors, with two-thirds of participants having zero bleeds. Fitusiran prophylaxis might show haemostatic efficacy in participants with haemophilia A or haemophilia B with inhibitors; therefore, the therapeutic might have the potential to improve the management of people with haemophilia.

DESIGN: We instituted a questionnaire-based survey to specialists managing PA, assessing the availability and affordability of investigations and treatment. Population and income status data were taken from the national census and registries.

RESULTS: Nine ASEAN country members (48 respondents) participated. While screening with aldosterone-renin-ratio is performed in all countries, confirmatory testing is routinely performed in only six countries due to lack of facilities and local assays, and cost constraint. Assays are only locally available in four countries, and some centers have a test turnaround time exceeding three weeks. In seven countries (combined population of 442 million), adrenal vein sampling (AVS) is not routinely performed due to insufficient radiological facilities or trained personnel, and cost constraint. Most patients have access to adrenalectomy and medications. In six countries, the cost of AVS and adrenalectomy combined is >30% of its annual gross domestic product per capita. While most patients had access to spironolactone, it was not universally affordable.

METHODS: The prospective, non-interventional explorer6 study included patients ≥12 years old with severe HA, severe/moderate HB or HAwI/HBwI of any severity, treated according to local standard of care (excluding previous/current exposure to concizumab or emicizumab). Baseline characteristics and historical clinical data were collected and patient-reported outcomes, including treatment burden, were assessed.

RESULTS: The explorer6 study enrolled 231 patients with haemophilia (84 HAwI/HBwI) from 33 countries. At baseline, patients with HA/HB treated with prophylaxis had the lowest median annualised bleeding rates (ABRs; 2.0), irrespective of haemophilia type; of these patients, 27.5% (HA) and 31.4% (HB) had target joints. Patients with HAwI/HBwI treated episodically reported the highest treatment burden. Of these patients, 28.5% (HAwI) and 25.1% (HBwI) performed sports activities in the month before screening.

METHODS: We conducted the explorer7 trial to assess the safety and efficacy of concizumab in patients with hemophilia A or B with inhibitors. Patients were randomly assigned in a 1:2 ratio to receive no prophylaxis for at least 24 weeks (group 1) or concizumab prophylaxis for at least 32 weeks (group 2) or were nonrandomly assigned to receive concizumab prophylaxis for at least 24 weeks (groups 3 and 4). After a treatment pause due to nonfatal thromboembolic events in three patients receiving concizumab, including one from the explorer7 trial, concizumab therapy was restarted with a loading dose of 1.0 mg per kilogram of body weight, followed by 0.2 mg per kilogram daily (potentially adjusted on the basis of concizumab plasma concentration as measured at week 4). The primary end-point analysis compared treated spontaneous and traumatic bleeding episodes in group 1 and group 2. Safety, patient-reported outcomes, and pharmacokinetics and pharmacodynamics were also assessed.

RESULTS: Of 133 enrolled patients, 19 were randomly assigned to group 1 and 33 to group 2; the remaining 81 were assigned to groups 3 and 4. The estimated mean annualized bleeding rate in group 1 was 11.8 episodes (95% confidence interval [CI], 7.0 to 19.9), as compared with 1.7 episodes (95% CI, 1.0 to 2.9) in group 2 (rate ratio, 0.14 [95% CI, 0.07 to 0.29]; P<0.001). The overall median annualized bleeding rate for patients receiving concizumab (groups 2, 3, and 4) was 0 episodes. No thromboembolic events were reported after concizumab therapy was restarted. The plasma concentrations of concizumab remained stable over time.