A Randomized, Multicenter, Open-Label, Phase III Clinical Trial to Evaluate the Efficacy, Safety, and Pharmacokinetics of Prophylactic Emicizumab Versus no Prophylaxis in Hemophilia A Patients With Inhibitors

This multicenter, open-label study will evaluate the safety, efficacy and pharmacokinetics of prophylactic emicizumab treatment in participants previously treated with episodic or prophylactic bypassing agents. Episodic bypassing agent participants will be randomized in a 2:1 fashion to receive emicizumab prophylaxis (Arm A) versus no prophylaxis (Arm B) and will be stratified across Arms A and B according to the number of bleeds they experienced over the last 24 weeks prior to study entry (less than [<] 9 or greater than or equal to [>/=] 9 bleeds); Arm B participants will have the opportunity to switch to emicizumab prophylaxis after at least 24 weeks on-study. Prophylactic bypassing agent participants will switch to emicizumab prophylaxis (Arm C) from the start of the trial; enrollment will be extended for 24 weeks after the last participant has enrolled in Arms A or B or until approximately 50 participants have enrolled in Arm C, whichever occurs first. Episodic bypassing agent participants who previously participated in the non-interventional study BH29768 (NCT02476942) who were unable to enroll in Arms A or B, or participants on prophylactic bypassing agents who were unable to enroll in Arm C, prior to their closure will have the opportunity to enroll in Arm D. Like participants in Arms A and C, Arm D participants will receive emicizumab prophylaxis from the start of the trial. All participants will continue to receive episodic bypassing agent therapy to treat breakthrough bleeds, preferably with recombinant activated factor VII (rFVIIa).