Long-term Safety and Efficacy Study of SPK-9001 in Individuals With Hemophilia B

Evaluation of the long term level of persistence and potential late or delayed adverse events
associated with SPK-9001, assessment of the durability of the transgene expression, and
determination of the effects of SPK-9001 on clinical outcomes in individuals who have
previously received a single administration of SPK-9001

Inclusion Criteria:

1. Evidence of a personally signed and dated informed consent document indicating that
the subject has been informed of all pertinent aspects of the study.

2. Willing and able to comply with scheduled visits, treatment plan, laboratory tests,
and other study procedures.

3. Subjects who met the C0371005 eligibility criteria, have received a single
administration of SPK-9001, and completed the required assessments in the C0371005
clinical study.

Exclusion Criteria:

1. Investigator site staff members directly involved in the conduct of the study and
their family members, site staff members otherwise supervised by the investigator, or
subjects who are Pfizer employees, including their family members, directly involved
in the conduct of the study.

2. Participation in other studies involving investigational drug(s) within the last 12
weeks prior to study entry, excluding participation in C0371005, and/or during study
participation.

3. Other acute or chronic medical or psychiatric condition including recent (within the
past year) or active suicidal ideation or behavior or laboratory abnormality that may
increase the risk associated with study participation or investigational product
administration or may interfere with the interpretation of study results and, in the
judgment of the investigator, would make the subject inappropriate for entry into this
study.

4. Fertile male subjects who are unwilling or unable to use a condom as outlined in this
protocol until 3 consecutive semen samples are negative in the vector shedding
analysis after the last dose of investigational product.

5. Subjects who will not consent for up to 5 years of safety follow-up.

6. Subjects who are unable or unwilling to comply with the study visits and requirements.

7. Subjects with any clinically significant medical condition that the Investigator
believes would pose as a safety risk or are not capable of performing the endpoints of
this study.