A Study to Evaluate the Safety, Efficacy, Pharmacokinetics and Pharmacodynamics of Emicizumab in Participants With Mild or Moderate Hemophilia A Without FVIII Inhibitors

Prior treatment

• History of illicit drug or alcohol abuse within 48 weeks prior to screening, in the investigator's judgment
• Previous (within the last 12 months) or current treatment for thromboembolic disease or signs of thromboembolic disease
• Planned surgery during the emicizumab loading dose phase (surgeries in participants on emicizumab from Week 5 onwards are allowed)
• Receipt of any of the following: An investigational drug to treat or reduce the risk of hemophilic bleeds within 5 half-lives of last drug administration with the exception of prior emicizumab prophylaxis; A non-hemophilia-related investigational drug within last 30 days or 5 half-lives, whichever is shorter; or Any other investigational drug currently being administered or planned to be administered

Other illness

• Inherited or acquired bleeding disorder other than mild or moderate congenital hemophilia A
• Other conditions that may currently increase the risk of bleeding or thrombosis
• History of clinically significant hypersensitivity associated with monoclonal antibody therapies or components of the emicizumab injection

Lab values

• Known HIV infection with CD4 counts \<200 cells per microlitre (/μL)
• Concomitant disease, condition, significant abnormality on screening evaluation or laboratory tests, or treatment that could interfere with the conduct of the study, or that would in the opinion of the investigator, pose an additional unacceptable risk in administering study drug to the participant
• Pregnant or breastfeeding, or intending to become pregnant during the study (women of childbearing potential must have a negative serum pregnancy test result within 7 days prior to initiation of study drug)

Other

• Inability to comply with the study protocol in the opinion of the investigator

• Diagnosis of mild (FVIII level between \>5% and \<40%) or moderate (FVIII level between ≥1% and ≤5%) congenital Hemophilia A without FVIII inhibitors
• Weight ≥3 kilograms (kg)
• Need for prophylaxis based on investigator assessment
• A negative test for inhibitor (i.e., \<0.6 Bethesda Units per milliliter \[BU/mL\]) within 8 weeks prior to enrollment
• No documented inhibitor (i.e., \<0.6 BU/mL), FVIII half-life \<6 hours, or FVIII recovery \<66% in the last 5 years
• Documentation of the details of prophylactic or episodic FVIII treatment and of number of bleeding episodes for at least the last 24 weeks prior to enrollment
• Adequate hematologic, hepatic, and renal function
• For women of childbearing potential: agreement to remain abstinent or use contraception (as defined in the protocol) during the treatment period and for at least 24 weeks after the final dose of study drug