Clinically significant factor VIII (FVIII) inhibitors were defined as a central laboratory confirmed positive inhibitor of greater than or equal to (>=) 0.6 Bethesda units (BU) using the Nijmegen modification of the Bethesda assay present at 2 consecutive blood draws within a 6-week interval and one of the following within 4 weeks before the initial or within 4 weeks following the second positive FVIII inhibitor sample collection: 1) the need for the participant to administer alternative hemostatic products in order to achieve sufficient efficacy, 2) >=2 events indicating a decrease in the efficacy of the study treatment. Percentage of participants who developed clinically significant Factor VIII inhibitor after study drug administration were reported.

Safety analysis population included all enrolled participants who received at least 1 dose of ReFacto AF.

Incremental recovery was the increase in circulating FVIII activity for every international unit (IU) of ReFacto AF administered per kilogram of body weight. It was measured in international units per deciliter (IU/dL) per international units per kilogram (IU/kg).

The pharmacokinetic (PK) parameter analysis population included all enrolled participants who received at least 1 dose of ReFacto AF. Here, "n" signifies participants who were evaluable at the specified time point for each arm respectively.

T1/2 was the time for the plasma concentration of drug to decrease by one-half of its original concentration.

PK parameter analysis population included all enrolled participants who received at least 1 dose of ReFacto AF. Here, "number of participants analyzed" signifies participants who were evaluable for this outcome measure. Data was not planned to be collected and analyzed for reporting arm "ReFacto AF: Less Than 6 Years", as pre-specified in protocol.

Drug clearance is a quantitative measure of the rate at which a drug substance is removed from the blood.

PK parameter analysis population included all enrolled participants who received at least 1 dose of ReFacto AF. Here, "number of participants analyzed" signifies participants who were evaluable for this outcome measure. Data was not planned to be collected and analyzed for reporting arm "ReFacto AF: Less Than 6 Years", as pre-specified in protocol.

ABR for each participant was calculated as the number of bleeds requiring administration of FVIII replacement product (taken from the Infusion Log Diary case report form), divided by the total therapy duration (in days), then multiplied by 365.25. ABR for the participants who reported following a primary or secondary prophylaxis, on-demand regimen or preventive regimen at baseline were reported.

Efficacy analysis population included all enrolled participants who received at least 1 dose of ReFacto AF. Here, "number of participants analyzed" signifies participants who were evaluable for this outcome measure and "n" signifies participants who were evaluable at the specified time points.

A 4-point scale of assessment of 'on-demand' treatment (administration of an unscheduled bolus infusion of Refacto-AF to stop bleeding) is defined as: 1. Excellent: Definite pain relief and/or improvement in signs of bleeding starting within 8 hours after an infusion, with no additional infusion administered. 2. Good: Definite pain relief and/or improvement in signs of bleeding starting within 8 hours after an infusion, with at least one additional infusion administered for complete resolution of the bleeding episode;or, Definite pain relief and/or improvement in signs of bleeding starting after 8 hours following infusion, with no additional infusion administered. 3. Moderate: Probable or slight improvement starting after 8 hours following the infusion, with at least one additional infusion administered for complete resolution of the bleeding episode. 4. No Response: No improvement at all between infusions or during the 24-hour interval following an infusion, or condition worsens.

Efficacy analysis population included all enrolled participants who received at least 1 dose of ReFacto AF. Here, "number of participants analyzed" signifies participants who were evaluable for this outcome measure and received at least 1 dose of ReFacto AF for at least one bleeding episode.

The infusion log diary case report form (CRF) was used to determine the number of on-demand (administration of an unscheduled bolus infusion of Refacto-AF to stop bleeding) ReFacto AF infusions administered to treat a new bleed. This was calculated by adding the initial for a new bleed (on-demand) infusion to any subsequent (on-demand) infusions for the same "previously treated bleed" (same bleed with same start date/time).

Efficacy analysis population included all enrolled participants who received at least 1 dose of ReFacto AF. Here, "number of participants analyzed" signifies participants who were evaluable for this outcome measure.

The number of breakthrough bleeds within 48 hours following a prophylaxis dose of ReFacto AF was summarized. The infusion log diary CRF was used to determine the number of infusions administered to treat a new bleed counting only those infusions which were administered <=48 hours after an infusion marked as "prophylaxis" (which had no associated bleed).

Efficacy analysis population included all enrolled participants who received at least 1 dose of ReFacto AF.

The average infusion dose (by weight) for each participant was calculated as his total factor FVIII consumption (in IU) divided by weight (in kg) divided by the number of infusions administered in total study duration. Data was reported separately for participants classified at baseline as following non-prophylaxis regimen (for example: on-demand regimen, preventive, or not specified), and participants classified at baseline following a primary or secondary prophylaxis regimen.

Efficacy analysis population included all enrolled participants who received at least 1 dose of ReFacto AF. Here, "n" signifies participants who were evaluable for each specified baseline category.

Total factor VIII consumption for each participant was calculated by sum of the total amount of ReFacto AF (in IU) infused for each ReFacto AF infusion (recorded in the infusion log diary CRF). Data was reported separately for participants classified at baseline as following non-prophylaxis regimen (for example: on-demand regimen, preventive, or not specified), and participants classified at baseline following a primary or secondary prophylaxis regimen.

Efficacy analysis population included all enrolled participants who received at least 1 dose of ReFacto AF. Here, "n" signifies participants who were evaluable for each specified baseline category.

LETE in on-demand setting was based on response to treatment of a bleeding episode. LETE in the on-demand setting occurred if participant recorded 2 successive "no response" ratings after 2 successive ReFacto AF infusions. Both infusions were to be administered at an interval of 24 hours for treatment of same bleeding event in absence of confounding factor which included: known presence or subsequent identification of a FVIII inhibitor, known inadequate dose for type and/or severity of bleed in opinion of investigator, delay of greater than 4 hours between onset of bleed to infusion, delay of greater than 24 hours before administration of a follow-up infusion, known compromised ReFacto AF, faulty administration of ReFacto AF, participant had an underlying, predisposing condition responsible for bleed in opinion of investigator (e.g., kidney stones or use of medications known to impair platelet function, such as aspirin or NSAIDs),or ongoing trauma responsible for continued bleeding.

Efficacy analysis population included all enrolled participants who received at least 1 dose of ReFacto AF. Here, "number of participants analyzed" signifies participants who were evaluable for this outcome measure and received treatment for at least one bleed.

LETE in the prophylaxis setting occurred if there was a spontaneous bleed within 48 hours (<=48 hours) after a regularly scheduled prophylactic dose of ReFacto AF (which was not used to treat a bleed) in the absence of confounding factors. Therefore, LETE in the prophylaxis setting is the occurrence of a bleed. Confounding factors include: Known presence or subsequent identification of a FVIII inhibitor, known inadequate prophylactic dose, known lack of adherence to the prescribed prophylaxis regimen, bleed occurs in a target joint identified at the start of the study, known compromised ReFacto AF, faulty administration of ReFacto AF, an underlying, predisposing condition responsible for the bleed in the opinion of the investigator (e.g., kidney stones or use of medications known to impair platelet function, such as aspirin or NSAIDs) or traumatic injury responsible for bleeding.

Efficacy analysis population included all enrolled participants who received at least 1 dose of ReFacto AF. Participants who received at least 1 prophylaxis dose of ReFacto AF were reported.

LETE in the low recovery setting was defined as lower than expected recovery of FVIII (in the opinion of investigator), following the infusion of ReFacto AF in the absence of confounding factors for the low recovery. The only confounding factors for low recovery are as follows: known presence or subsequent identification of a FVIII inhibitor, known compromised ReFacto AF, faulty administration of ReFacto AF, including inadequate dosing.

Efficacy analysis population included all enrolled participants who received at least 1 dose of ReFacto AF.

Participants who met the dose escalation criteria were prescribed a higher dose and/or more frequent doses as per the investigator's discretion.

Efficacy analysis population included all enrolled participants who received at least 1 dose of ReFacto AF. Participants who used a prophylaxis regimen were analyzed for this outcome measure.

The PK parameter analysis population included all enrolled participants who received at least 1 dose of ReFacto AF.

AUCinf is the area under the plasma concentration-time profile from time 0 extrapolated to infinite time. It was calculated as International units*hour per milliliter (IU*hr/mL).

PK parameter analysis population included all enrolled participants who received at least 1 dose of ReFacto AF. Here, "number of participants analyzed" signifies participants who were evaluable for this outcome measure. Data was not planned to be collected and analyzed for reporting arm "ReFacto AF: Less Than 6 Years", as pre-specified in protocol.

AUClast is the area under the plasma versus time curve from time zero to time of last measurable concentration (AUClast)

PK parameter analysis population included all enrolled participants who received at least 1 dose of ReFacto AF. Here, "number of participants analyzed" signifies participants who were evaluable for this outcome measure. Data was not planned to be collected and analyzed for reporting arm "ReFacto AF: Less Than 6 Years", as pre-specified in protocol.

Volume of distribution was defined as the theoretical volume in which the total amount of drug was uniformly distributed to produce the desired blood concentration of a drug. Steady state volume of distribution (Vss) was the apparent volume of distribution at steady-state.

PK parameter analysis population included all enrolled participants who received at least 1 dose of ReFacto AF. Here, "number of participants analyzed" signifies participants who were evaluable for this outcome measure. Data was not planned to be collected and analyzed for reporting arm "ReFacto AF: Less Than 6 Years", as pre-specified in protocol.

MRT was calculated as AUMCinf / AUCinf-TI/2, where AUMCinf is the area under the first moment curve from time zero to infinity and TI was the duration of infusion.

PK parameter analysis population included all enrolled participants who received at least 1 dose of ReFacto AF. Here, "number of participants analyzed" signifies participants who were evaluable for this outcome measure. Data was not planned to be collected and analyzed for reporting arm "ReFacto AF: Less Than 6 Years", as pre-specified in protocol.

An adverse event (AE) was any untoward medical occurrence in a participant who received study treatment without regard to possibility of causal relationship. An SAE was an AE resulting in any of the following outcomes or deemed significant for any other reason: death, initial or prolonged inpatient hospitalization, life-threatening experience (immediate risk of dying), persistent or significant disability or incapacity, congenital anomaly. Treatment-emergent are events between first dose of study drug and up to 30 days after last dose that were absent before treatment or that worsened relative to pretreatment state. AEs included both serious and non-serious adverse events.

Safety analysis population included all enrolled participants who received at least 1 dose of ReFacto AF.