ATHN 2: Factor Switching Study

This non-interventional, minimal risk cohort study will enroll patients with Hemophilia A or
B who are planning or have recently switched to a new Factor product. The study will have 2
Arms, prospective and retrospective. The Prospective Arm will enroll patients who plan to
switch to a new factor. The Retrospective Arm will enroll patients who have recently switched
to a new factor (within the previous 50 weeks). Patient will be seen at baseline and for up
to 4 additional visits, and quarterly follow-up by phone. Required study visits will be
planned to coincide with routine follow-up visits whenever possible.

Please note that Factor Replacement Products are not being provided by the study.

The primary objective is to assess and characterize the rate of inhibitor development within
one (1) year or fifty (50) exposure days, whichever is first, after switching clotting factor
replacement products in previously treated patients (PTPs) with hemophilia A or B.

Data collected will include eligibility, demographics, medical history, hemophilia history
(clotting history, product history, genotype and family history), inhibitor history,
co-morbidities at baseline (i.e., HIV, Hepatitis C.), detailed clotting factor replacement
product(s) usage and switching plan, and reasons for switching factor products. Also targeted
physical exams will be performed at baseline and during follow-up, and targeted concomitant
medication data will be collected. Data collection will also include patient-reported
outcome(s) after 1 year, bleeding events, surgeries, laboratory Inhibitor testing and details
regarding testing methodology, pharmacokinetic (PK) data (if known), new diagnoses, and
co-morbidities (targeted), Safety/Adverse Events using European Union Hemophilia Safety
Surveillance (EUHASS) definitions.

This study will evolve to include any newly approved (since January 2013) factors as they
come to market. Cohorts will be defined by the brand/type of new clotting factor replacement
product approved after January 1, 2013. The current list of specific new Factor VIII
replacement products include Eloctate® (Bioverativ) and NovoEight® (NovoNordisk); Factor IX
replacement products include Alprolix® (Bioverativ), Rixubis® (Baxalta), and IXinity®
(Emergent Biosolutions). Others are both now available and imminent and include: Adynovate®,
Idelvion®, Afstyla®, Kovaltry® and Jivi®.

The over-arching rationale for this protocol is that a pragmatic study which is consistent
with real world practices across a wide range of patients that is not principally tied to a
particular manufacturer or product may be of great advantage to the entire hemophilia
community.

Study Duration

- Subjects on prophylaxis will be followed on study for up to 1 year. Each subject will be
seen during a study visit or contacted by telephone at least once every 3 months (i.e.,
quarterly). Patients may participate for multiple 'cycles', if they switch factor
products more than once while the study is actively recruiting.

Treatment regimen will be at the discretion of the subject's hemophilia caregivers. No
treatment is being provided by the study.

- Substudies A number of substudies are planned with pharmaceutical sponsors to collect
information from patients about their products' use. Participation in these optional
substudies (product-specific modules) will be planned to coincide with study visits.
These modules will collect information from subjects about their perception and use of
factor use/treatment, physical activity levels and other general health questions. These
data will be collected via questionnaire, primarily via phone.

Concomitant and Excluded Therapies

- Immune tolerance therapy is excluded on study. This includes immunosuppressive
treatments used to eradicate inhibitors. Steroid treatments for allergic disorders and
asthma, are allowed.

Data Collection System

- All data collected will be entered into electronic case report forms (eCRFs) within the
secure ATHN Study Manager system. Subject Identifiers (IDs) will be generated in
Clinical Manager.

- Reimbursement will be managed by each participating HTC. Most study centers will
reimburse study subjects for travel and parking, but this varies by center.

Inclusion Criteria

- Moderate or Severe Congenital Hemophilia A or B (FVIII or FIX clotting activity less
than or equal to 5% of normal).

- Able to give informed consent (by patient or parent/authorized guardian).

- Previously treated with plasma-derived or recombinant clotting factor replacement
products with at least 50 exposure days (as assessed either from direct clinical
records in children under age 5, or by clinical history of dosing in older patients).
For Arm B being enrolled retrospectively, this previous treatment must be prior to
product switch under study.

- Planning to switch, or recently switched within the previous 50 weeks, to a new brand
or type of replacement factor VIII or IX, FDA approved after January 1, 2013.

- Arm B only: Negative inhibitor screen within the last 6 months prior to switching.

Note: History of prior transient inhibitor or inhibitor eradicated by immune tolerance
induction (ITI) are eligible.

Exclusion Criteria

- Presence of any known bleeding disorder other than hemophilia A or B (i.e., patients
with concurrent hemophilia and a second hemostatic defect are NOT eligible). Low Von
Willebrand Factor (VWF) without VWF diagnosis are not excluded.

- Presence of an active inhibitor >0.6 BU for factor VIII, > 0.4 BU for factor IX at the
time of eligibility assessment. Detection of such an inhibitor at the baseline visit
prior to dosing with the new product (Arm A), or after dosing with new factor dosing
(Arm B), would result in early termination without other study assessments.

- Currently undergoing ITI.

- Immunosuppressive therapy (cyclophosphamide, mycophenolate, IVIG) within 90 days and
Rituximab within 6 months; topical steroid treatments and short course steroids for
asthma or allergy allowed.

- Previous participation in Phase I, II or III interventional trials of the factor
product being switched to.