Phase 3b Continuation Study of the Safety and Efficacy of Prophylactic BAX 855 in PTPs With Severe Hemophilia A

Main Inclusion Criteria:

- Participants from other BAX 855 studies can be provided with the continuation study
informed consent form (ICF) prior to the end of study visit to review and consider
participation in this continuation study. These participants will complete any
additional screening assessments within 2 weeks of the previous study's end of study
visit and will return to the study site within 6 weeks of the previous study end of
study visit to confirm eligibility for this continuation study.

- BAX 855 naïve participants who are ≥ 12 years of age can only be enrolled in this
continuation study after enrollment in the phase 2/3 pivotal study is closed. BAX 855
naïve participants who are < 12 years of age and in countries where the pediatric PTP
study is being conducted can only be enrolled in this continuation study after
enrollment in the pediatric PTP study is closed.

- Participants coming from other BAX 855 studies into the continuation study, will be
considered enrolled only after they have completed all procedures and assessments at
the End of Study Visit in the previous BAX 855 study

- Participant and/or legal representative has/have voluntarily provided signed informed
consent

- Participant is from 0 to 75 years of age at screening

- Participant is male with severe hemophilia A (Factor VIII (FVIII) clotting activity <
1%) as confirmed by central laboratory at screening (after at least a 72-hour washout
period) or a documented FVIII clotting activity <1% (confirmation is only required for
BAX 855 naïve participants)

- Participant has been previously treated with plasma-derived FVIII concentrates or
recombinant FVIII for ≥150 documented exposure days (EDs)

- Participant is currently receiving prophylaxis or on-demand therapy with FVIII

- Participant has a Karnofsky or Lansky performance score of ≥ 60.

- Participant is human immunodeficiency virus negative (HIV-); or HIV+ with stable
disease and CD4+ count ≥ 200 cells/mm^3, as confirmed by central laboratory at
screening.

- Participant is hepatitis C virus negative (HCV-) by antibody or PCR testing (if
positive, antibody titer will be confirmed by PCR), as confirmed by central laboratory
at screening; or HCV+ with chronic stable hepatitis.

- Participant is willing and able to comply with the requirements of the protocol

Main Exclusion Criteria:

- Participant has detectable FVIII inhibitory antibodies (≥ 0.4 Bethesda unit (BU) using
the Nijmegen modification of the Bethesda assay) as confirmed by central laboratory at
screening.

- Participant has history of FVIII inhibitory antibodies (≥ 0.4 BU using the Nijmegen
modification of the Bethesda assay or ≥ 0.6 BU using the Bethesda assay) at any time
prior to screening.

- Participant has been diagnosed with an inherited or acquired hemostatic defect other
than hemophilia A (eg, qualitative platelet defect or von Willebrand's disease).

- Participant has known hypersensitivity towards mouse or hamster proteins, polyethylene
glycol (PEG), or Tween 80.

- Participant has severe chronic hepatic dysfunction.

- Participant has severe renal impairment.

- Participant has current or recent (<30 days) use of other PEGylated drugs prior to
study participation or scheduled use of such drugs during study participation.

- Participant has participated in another clinical study involving an investigational
product (IP) other than BAX 855 or device within 30 days prior to enrollment or is
scheduled to participate in another clinical study involving an IP or investigational
device during the course of this study.

- Participant has medical, psychiatric, or cognitive illness or recreational
drug/alcohol use that, in the opinion of the investigator, would affect participant
safety or compliance.

- Participant is a family member or employee of the investigator.