This is an open-label, extension study enrolling patients who have successfully completed all assessments in Study CT-AMT-060-01 (Years 1-5). Assessment phase will begin at Visit 36 (the first clinical visit in this extension study, approximately 5.5 years after the initial dosing visit Study CT-AMT-060-01) and go to Visit 45 (10-years post-dosing in Study CT-AMT-060-01).

Inclusion Criteria:

• - Subjects with congenital hemophilia B who completed Study CTAMT-060-01
• - Able to provide informed consent following receipt of verbal and written
• information about the trial.

Exclusion Criteria:

• - Enrolled subjects will have already been assessed based on the exclusion
• criteria for Study CT-AMT-060-01.

Male subjects with severe or moderately severe haemophilia B, who previously received an infusion of AMT-060 and completed all assessments in Study CTAMT-060-01

CSL will consider on a case-by-case basis requests to share Individual Patient Data (IPD) with external bona-fide, qualified scientific and medical researchers. For information on the process and requirements for submitting a voluntary data sharing request for IPD, please contact CSL at clinicaltrials@cslbehring.com.

Requests for IPD will generally be considered once review by major regulatory authorities (ie FDA, EMA) is complete and the primary publication is available.

Proposed research should seek to answer a previously unanswered important medical or scientific question.

Applicable country specific privacy and other laws and regulations will be considered and may prevent sharing of IPD.

If the request is approved and the researcher has executed an appropriate data sharing agreement, IPD that has been appropriately anonymized will be available.