A Study of Recombinant Von Willebrand Factor (rVWF) in Pediatric and Adult Participants With Severe Von Willebrand Disease (VWD)

An adverse event (AE): any untoward medical occurrence in a participant administered a pharmaceutical product; the untoward medical occurrence does not necessarily have a causal relationship with this treatment. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with the use of a medicinal (investigational) product whether or not it is related to medicinal product. TEAE was defined as any AE that started after the first administration of study drug in this continuation study. Serious TEAEs: any untoward medical occurrence that: 1) results in death, 2) is life-threatening, 3) requires inpatient hospitalization or prolongation of existing hospitalization, 4) results in persistent or significant disability/incapacity, 5) leads to a congenital anomaly/birth defect in the offspring of the participant or 6) is medically important.

An AE is defined as any untoward medical occurrence in a participant administered IP that does not necessarily have a causal relationship with the treatment. TEAE was defined as any AE that started after the first administration of study drug in this continuation study. Severity of TEAEs was determined by following definitions: Mild: No limitation of usual activities; Moderate: Some limitation of usual activities and may required therapeutic intervention; Severe: Inability to carry out usual activities with sequelae, which required therapeutic intervention. Number of participants with TEAEs based on severity of TEAEs were reported.

An AE is defined as any untoward medical occurrence in a participant administered IP that does not necessarily have a causal relationship with the treatment. TEAE was defined as any AE that started after the first administration of study drug in this continuation study. A physician/investigator made the assessment of relationship to investigational product for each AE. Number of participants with TEAEs based on causality were reported.

Thromboembolism defined as formation of a clot (thrombus) in a blood vessel that breaks loose, is carried by the blood stream and could plug another vessel. Number of participants with thromboembolic events as TEAEs of special interest were reported.

Hypersensitivity (also called hypersensitivity reaction or intolerance) defined as undesirable reactions produced by the normal immune system, including allergies and autoimmunity. Potential hypersensitivity events were identified by broad search criteria and then medically assessed. Number of participants with hypersensitivity reactions as TEAEs of special interest was calculated.

Three functional VWF assays for von Willebrand factor collagen binding (VWF:CB), von Willebrand factor: Ristocetin Cofactor (VWF:RCo) and von Willebrand factor VIII B (VWF:FVIIIB) were used to test the presence of neutralizing anti-VWF antibodies. Neutralizing antibodies to VWF:RCo, VWF:CB and VWF:FVIIIB activities were measured by assays based on the Bethesda assay established for quantitative analysis of FVIII inhibitors (Nijmegen modification of the Bethesda assay). Only confirmed neutralizing anti -VWF antibodies were considered inhibitors. Number of participants who developed neutralizing antibodies to rVWF were assessed.

Three functional VWF assays for von Willebrand factor collagen binding (VWF:CB), von Willebrand factor: Ristocetin Cofactor (VWF:RCo) and von Willebrand factor VIII B (VWF:FVIIIB) were used to test the presence of neutralizing anti-VWF antibodies. Neutralizing antibodies to VWF:RCo, VWF:CB and VWF:FVIIIB activities was measured by assays based on the Bethesda assay established for quantitative analysis of FVIII inhibitors (Nijmegen modification of the Bethesda assay). Only confirmed neutralizing anti -VWF antibodies were considered inhibitors. Number of participants who developed neutralizing antibodies to FVIII were assessed.

The presence of total binding anti-VWF antibodies was determined by an enzyme-linked immunosorbent assay (ELISA) employing polyclonal anti-human Immunoglobulin (Ig) antibodies (IgG, IgM and IgA). Number of participants who developed of total binding antibodies to rVWF were assessed.

Binding antibodies against FVIII were analyzed using a proprietary enzyme immunoassay. Number of participants who developed of total binding antibodies to FVIII were assessed.

Total Ig antibodies (IgG, IgA, IgM) against CHO protein were analyzed using ELISA. Number of participants who developed binding antibodies to CHO proteins were assessed.

Detection and quantification of IgG antibodies originating from human plasma that were directed against mouse-IgG (HAMA: human anti- mouse antibodies) were assessed using ELISA (Medac, Hamburg, Germany). Number of participants who developed binding antibodies to Mouse IgG were assessed.

Total Ig antibodies (IgG, IgA, IgM) against human furin were analyzed using ELISA. Number of participants who developed binding antibodies to rFurin were assessed.

Vital signs included blood pressure (systolic and diastolic), pulse rate, respiratory rate and body temperature. Number of participants with clinically significant change from baseline in vital signs were assessed.

Clinical laboratory parameters included serum chemistry, hematology and urinalysis assessments. Number of participants with clinically significant change from baseline in clinical laboratory parameters were assessed.

sABR was derived as [number of treated bleeds] / [duration in years]. Bleeds with unknown causality were considered as spontaneous. Bleeds were categorized based on the investigator assessment of cause. sABR during prophylaxis treatment with rVWF (vonicog alfa) while enrolled in the study were reported.

Categorized as ≥ 0 to < 1 infusion per week, ≥ 1 to < 2 infusions per week, ≥ 2 to < 3 infusions per week, ≥ 3 infusions per week. The number of participants categorized based on number of infusions per week during prophylactic treatment with rVWF (vonicog alfa) were reported.

The sABR was the number of spontaneous bleeds divided by the observation period in years, where an observation period = (date of completion/termination-date of first dose+1)/365.2425. sABR was categorized based on number of BEs as 0, greater than (>) 0 through 2, >2 through 5, >5 during the prophylactic treatment with rVWF (vonicog alfa). Bleeding at multiple locations related to the same injury was counted as single BE. BEs of unknown cause were counted as spontaneous bleeds. Number of participants categorized based on sABR during prophylactic treatment with rVWF (vonicog alfa) were reported.

Time to event estimates and confidence intervals obtained from Kaplan-Meier analysis. Participants with 0 bleeds during each study period were censored at the date of the last day in that study period.

sABR was derived as [number of treated bleeds] / [duration in years]. sABR for BEs based on location of bleeding: Skin, Muscle, Mucosal Nasal, Mucosal Oral, Joint, Gastrointestinal (GI), Menstrual/Heavy Menstrual, Venipuncture Site, Soft Tissue, Body Cavity, Hematuria, Central Nervous System (CNS) and Other, while on prophylactic treatment with rVWF (vonicog alfa) were reported.

Total number of infusions during prophylactic treatment with rVWF (vonicog alfa) were reported.

Average number of infusions per week during prophylactic treatment with rVWF (vonicog alfa) were reported.

For each participant, the body weight-adjusted dose (IU/kg) was derived as the number of units of rVWF infused (IU) divided by the last available body weight (kilogram [kg]) prior to the infusion. Total weight adjusted consumption of rVWF (vonicog alfa) per participant during prophylactic treatment with rVWF (vonicog alfa) was reported as International Units per kilogram (IU/kg).

Transfusion free maintenance of hemoglobin levels during prophylactic treatment with rVWF (vonicog alfa) were reported.

Change from baseline in ferritin levels over time during prophylactic treatment with rVWF (vonicog alfa) were reported. Baseline Ferritin lab assay for rollover participants in cohorts 1, 2 and 3 were not mandatory per protocol at the Screening Visit of this study as the results from End of Study (EOS) visit of parent studies were expected to be utilized for rollover cohorts 1-3. However, many participants in cohort 1 did not have this data collected at EOS Visit of parent study 071301 and no participant in cohorts 2 and 3 had this data collected at EOS Visit of parent studies 071301 and 071102.

Overall Hemostatic Efficacy Rating at resolution of bleed with respect to treatment of BEs for initial 12 months of study in OD cohorts. Hemostatic efficacy for treatment of BEs was rated on 4-point Likert scale as:excellent=full relief of pain\&cessation of objective signs of bleeding after single infusion,no additional infusion is required for control of bleeding\&administration of further infusion to maintain hemostasis would not affect scoring;good=definite pain relief\&/or improvement in signs of bleeding after single infusion,possibly requires >2 infusions for complete resolution\&administration of further infusion to maintain hemostasis would not affect scoring;fair=probable\&/or slight relief of pain\&slight improvement in signs of bleeding after single infusion,required multiple infusions for complete resolution;none=no improvement of signs/symptoms or conditions worsen.Missing=number of unique BEs without any overall hemostatic efficacy rating at resolution of breakthrough BE.

Number of infusions of rVWF (vonicog alfa) utilized to treat BEs during OD treatment while enrolled in the study were reported.

Number of infusions of ADVATE (rFVIII, octocog alfa) utilized to treat BEs during OD treatment while enrolled in the study were reported.

Weight-adjusted consumption (IU/kg) was derived as the total units infused (IU) divided by the last available body weight (kg) prior to the infusion. Weight-adjusted consumption of rVWF (vonicog alfa) per bleeding episode during OD treatment while enrolled in the study were reported.

Weight-adjusted consumption (IU/kg) was derived as the total units infused (IU) divided by the last available body weight (kg) prior to the infusion. Weight-adjusted consumption of ADVATE (rFVIII, octocog alfa) per bleeding episode during OD treatment while enrolled in the study were reported.