Study designs of the HAVEN 1-4 trials.^14-17 ∗Participants receiving episodic BPAs before study entry were randomized to emicizumab prophylaxis (Arm A) or no emicizumab (Arm B, control), and those receiving prophylactic BPAs before study entry received emicizumab prophylaxis (Arm C). After completing the first 24 weeks of the trial, participants in the control arm (Arm B) could receive emicizumab prophylaxis. A fourth arm also receiving emicizumab prophylaxis (Arm D) comprised participants enrolled after Arms A to C closed. †One participant in HAVEN 1 assigned to an active arm discontinued before the first emicizumab treatment and was excluded from the analyses. ‡Maintenance doses. With the exception of the HAVEN 4 pharmacokinetics run-in cohort (n = 7), all maintenance doses were preceded by loading doses of 3.0 mg/kg QW for 4 weeks. §Adolescents aged 12 to 17 years were also eligible to enroll in HAVEN 2 if they weighed <40 kg; 3 participants were aged 12 to 17. ǁParticipants receiving episodic FVIII before study entry were randomized (2:2:1) to emicizumab 1.5 mg/kg QW (Arm A), emicizumab 3 mg/kg Q2W (Arm B), or no prophylaxis (Arm C, control), and those receiving prophylactic FVIII before study entry received emicizumab 1.5 mg/kg QW (Arm D). ¶One participant in HAVEN 3 assigned to no prophylaxis was lost to follow-up before switching to emicizumab and was therefore not treated; hence, they have been excluded from the analyses. F, factor; QW, once weekely; Q2W, once every 2 weeks; Q4W, once every 4 weeks.