A Study of Vonicog Alfa (rVWF) in Children With Severe Von Willebrand Disease (vWD)

1. The participant has a documented diagnosis of severe VWD (baseline von Willebrandfactor ristocetin cofactor activity [VWF:RCo] <20 international units per deciliter [IU/dL]) with a history of replacement therapy with VWF concentrate required tocontrol bleeding and a diagnosis of VWD type 1, type 2 (2A, 2B, 2M, 2N), or type 3.Diagnosis is confirmed, as applicable, by genetic testing and/or by multimeranalysis, which may be documented in participant's history or at screening.

2. The participant is <18 years of age at the time of screening.

3. Prescreening treatment requirements:

4. The participant has been receiving OD therapy with VWF products for at least 12months (for participants >=2 years of age) prior to screening, has experiencedat least 1 VWF-treated bleeding event during (excluding menorrhagia/heavymenstrual bleeding [HMB], as applicable) in the last 12 months, andprophylactic treatment is recommended by the investigator (Prior ODparticipants); or

5. The participant has been receiving prophylactic treatment with pdVWF productsfor at least 12 months prior to screening (for participants >=2 years of age)and switching to prophylaxis with vonicog alfa (rVWF) is recommended by theinvestigator (Switch participants).

6. For participants <2 years of age, the required duration for prior OD therapywith VWF products or for prior prophylactic treatment with pdVWF products is atleast 6 months. Prior OD participants <2 years of age should have experiencedat least 1 VWF-treated bleeding event during the last 6 months based on medicalrecords and be recommended to receive prophylactic treatment by theinvestigator.

7. For participants >=2 years of age, the participant has available records thatreliably evaluate type, frequency, severity, and treatment of BEs for at least 12months preceding enrollment. For participants <2 years of age, the participant hasavailable records that reliably evaluate type, frequency, severity and treatment ofBEs for at least 6 months preceding enrollment.

8. If >=12 years old at the time of screening, the participant has a body mass index (BMI) >=15 but <40 kilogram per square meter (kg/m^2). If >=2 to <12 years old atthe time of screening, the participant has a BMI of >=5th and <95th percentile (perCenters for Disease Control and Prevention [CDC] clinical charts). For youngerparticipants who are <2 years old, the "weight-for-age" clinical charts (5th to 95thpercentile) provided by the CDC should be utilized to ensure the participant has abody weight of >=5th and <95th percentile based on gender (for clinical chartsprovided by CDC, refer to: https://www.cdc.gov/growthcharts/clinical_charts.htm).

9. Female participants of childbearing potential (that is, had onset of menses/reachedpuberty) must have a negative blood/urine pregnancy test result at screening andagree to employ highly effective birth control measures for the duration of theirparticipation in the study.

10. The participant has voluntarily provided assent (if appropriate) and the legallyauthorized representative(s) has provided informed consent.

11. The participant and/or legally authorized representative is willing and able tocomply with the requirements of the protocol, which should also be confirmed basedon a prescreening evaluation held between the investigator and the sponsor to ensureno eminent risk is present that could challenge the participant's compliance withthe study requirements.

Exclusion Criteria:

1. The participant has been diagnosed with pseudo VWD or another hereditary or acquiredcoagulation disorder other than VWD (example, qualitative and quantitative plateletdisorders or elevated prothrombin time/international normalized ratio 1.4).

2. The participant has a history or presence of a VWF inhibitor at screening.

3. The participant has a history or presence of an factor VIII (FVIII) inhibitor with atiter >=0.6 Bethesda units per milliliter (/mL).

4. The participant has a known hypersensitivity to any of the components of the studydrugs, such as mouse or hamster proteins.

5. The participant has a medical history of immunological disorders, excluding seasonalallergic rhinitis/conjunctivitis, mild asthma, food allergies, or animal allergies.

6. The participant has a medical history of a thromboembolic event.

7. The participant is human immunodeficiency virus (HIV)-positive with an absolutehelper T cell (CD4) count <200 per cubic millimeter or microliter (/mm^3).

8. The participant has been diagnosed with significant liver disease per theinvestigator's medical assessment of the participant's current condition or medicalhistory or as evidenced by, but not limited to, any of the following: serum alanineaminotransferase (ALT) greater than 5 times the upper limit of normal (ULN),hypoalbuminemia, portal vein hypertension (example, presence of otherwiseunexplained splenomegaly, history of esophageal varices), or liver cirrhosisclassified as Child-Pugh class B or C.

9. The participant has been diagnosed with renal disease, with a serum creatinine level >=2.5 milligram per deciliter (mg/dL).

10. The participant has a platelet count <100,000/mL at screening (because participantswith type 2B VWD are considered eligible for this study, for participants with type 2B VWD, platelet count[s] at screening will be evaluated in consultation with thesponsor, taking into consideration historical trends in platelet counts and theinvestigator's medical assessment of the participants condition).

11. The participant has been treated with an immunomodulatory drug, excluding topicaltreatment (example, ointments, nasal sprays), within 30 days prior to signing theinformed consent (or assent, if appropriate).

12. The participant is pregnant or lactating at the time of enrollment.

13. The participant has cervical or uterine conditions causing menorrhagia ormetrorrhagia (including infection, dysplasia).

14. The participant has participated in another clinical study involving another IP orinvestigational device within 30 days prior to enrollment or is scheduled toparticipate in another clinical study involving an IP or investigational deviceduring the course of this study.

15. The participant has not received OD or prophylactic treatment with a VWF productprior to this study.

16. The participant has a progressive fatal disease and/or life expectancy of less than 15 months.

17. The participant is unable to complete screening procedures and/or comply with therequirements of the protocol in the opinion of the investigator, based on the jointprescreening evaluation held between the investigator and the sponsor.

18. The participant has a mental condition rendering him/her unable to understand thenature, scope, and possible consequences of the study and/or evidence of anuncooperative attitude.

19. The participant is member of the study team or in a dependent relationship with oneof the study team members, which includes close relatives (that is, children,partner/spouse, siblings, and parents) as well as employees.