The objective of this study is to determine the long term safety and tolerability of an additional infusion of 10 billion VRX496 gene-modified CD4 T cells with a focus on evaluating additional therapeutic benefits with respect to viral load and CD4 counts.

The study has concluded it's 9-month active phase. Subjects are currently in a 15-year Long Term Follow-up Phase of the study.

In keeping with the recently released Guidance on Monitoring For Delayed Adverse Events, that states that for the first 5 years all subjects should undergo monitoring of vector sequences every 6 months, subjects will visit the clinic at a maximum of 6 months intervals for a blood test evaluating persistence of vector sequences.

Therefore for the first 5 years, subjects will have 6 months visits for safety assessment. For years 6 to 15, subjects will be contacted by phone or mail. At these contacts, subjects will be asked about their health status.

Inclusion Criteria:

• Ability and willingness to give written informed consent in accordance with institutional and federal guidelines and to comply with the investigational nature of the study and the related requirements.
• Subjects who have successfully completed participation in the VRX496-USA-05-002 trial.
• Subjects who initiated or changed to a new ARV regimen more than 3 months prior to Entry Assessment are eligible.
• Subjects that who (1) if on ARVs and are willing to continue on the current therapy unchanged, or (2) if not on ARV willing to remain off ARVs for the duration of the trial i.e. 9 months. However, if there is clinical need to start or change ARV therapy, then it is permitted to do so.

Exclusion Criteria:

• CD4 counts decreased by ≥25% from baseline in main study.
• Viral load increased by ≥ 1.0 log from baseline in main study or ≥ 200,000.
• Female subjects who are of reproductive potential who have a positive serum B HCG at the Entry Assessment visit or are not willing to use a reliable method of barrier contraception.
• Are breast-feeding.
• Subjects who are actively using injection drugs or other substance abuse (such as extensive alcohol or narcotic use).
• Any medical condition(s) which, in the opinion of the investigator, would interfere with the subject's ability to participate in or adhere to the requirements of this protocol
• Active HIV-related or non HIV-related illness
• Subjects who do not have additional cell product available