Phase 1 Dose Escalation Study of Autologous T-cells Genetically Modified at the CCR5 Gene by Zinc Finger Nucleases in HIV-Infected Patients

Inclusion Criteria:

- Documented HIV infection prior to study entry

- Must be willing to comply with study-mandated evaluations; including not changing
their antiretroviral regimen (unless medically indicated) during the study period.

Cohort 1, 2 and 3 (Enrollment Completed)

Cohort 5:

- Must have received HAART therapy, and had undetectable viral loads for at least 1
year.

- HIV-1 RNA < 50 copies/mL obtained within 60 days prior to study entry performed with
an ultrasensitive HIV-1 PCR assay.

- CD4+ T cell count >350 cells/mm3

- Heterozygous for the CCR5 delta-32 mutation

- On stable antiretroviral medication (no changes to treatment within 4 weeks of
screening and willing to discontinue current antiretroviral therapy during the
structured therapy interruption

Cohort 4

- On stable antiretroviral medication (no changes to treatment within 4 weeks of
screening and willing to continue on current antiretroviral therapy through week 8
after infusion

- CD4+ T cell count >350 cells/mm3.

- HIV-1 >1,000 copies/mL at screen and not responding to current antiviral therapy
(i.e. HIV-RNA plasma levels > 1000 copies/ml after at least 12 weeks of stable,
unchanged ARV therapy).

Exclusion Criteria:

- Acute or chronic hepatitis B or hepatitis C infection

- Active or recent (in prior 6 months) AIDS defining complication.

- Any cancer or malignancy within the past 5 years, with the exception of successfully
treated basal cell or squamous cell carcinoma of the skin or low grade (0 or 1) anal
or cervical dysplasia.

- Current diagnosis of NYHA grade 3 or 4 CHF, uncontrolled angina or uncontrolled
arrhythmias.

- History or any features on physical examination indicative of a bleeding diathesis.

- Previous treatment with any HIV experimental vaccine within 6 months prior to
screening, or any previous gene therapy using an integrating vector.

- Use of chronic corticosteroids, hydroxyurea, or immunomodulating agents (e.g.,
interleukin-2, interferon-alpha or gamma, granulocyte colony stimulating factors,
etc.) within 30 days prior to enrollment

- Breast-feeding, pregnant or unwilling to use acceptable methods of birth control for
6 months following the last infusion of SB-728-T cells.

- warfarin or any other medication that is likely to affect platelet function or other
aspects of blood coagulation during the 2 week period prior to leukapheresis.

- Active drug or alcohol use or dependence

- Serious illness requiring systemic treatment and/or hospitalization within 30 days
prior to study entry.

- Recent vaccination or intercurrent illness (within 5 weeks prior to infusion)

- Have an allergy or hypersensitivity to study product excipients (human serum albumin,
DMSO and Dextran 40).

- Subjects who are currently taking maraviroc or have received maraviroc within 6
months prior to screening.

Cohort 4 only:

- HIV-1 RNA >1,000 copies/mL at screen and not responding to current antiviral therapy

- CD4+ T cell count >350 cells/mm3