Switching From Efavirenz to Atazanavir/ Ritonavir in HIV-infected Subjects With Good Virologic Suppression

Inclusion Criteria: 1. HIV infection 2. Age \> or = 18 years old. 3. Signed informed consent. 4. Clinical lipoatrophy of at least moderate severity and in at least two different areas of the following: face, arms, legs, or buttocks (as self reported by the patient and confirmed by the physician). 5. Women of childbearing potential must be using an adequate method of contraception to avoid pregnancy throughout the study in such a manner that the risk of pregnancy is minimized. 6. All subjects must not participate in a conception process (e.g. active attempt to become pregnant or to impregnate, sperm donation, in vitro fertilization), and if participating in sexual activity that could lead to pregnancy, the female subject/ male partner must use condoms (male or female) in addition to one of the following forms of contraception while on study: either a spermicidal agent, diaphragm, cervical cap, IUD, or hormonal-based contraception. Prior to study enrollment, women of childbearing potential (WOCBP) must be advised of the importance of avoiding pregnancy during trial participation and the potential risk factors for an unintentional pregnancy. In addition, men enrolled on this study should understand the risks to any sexual partner of childbearing potential and should practice an effective method of birth control. 7. Receiving EFV-containing antiretroviral regimen for at least the last 48 weeks prior to study entry. Backbone NRTI regimens can include tenofovir, abacavir, emtricitabine, and/ or lamivudine. Backbone NRTI regimens cannot include zidovudine, stavudine, or didanosine. Breaks in therapy for a maximum of 5 consecutive days will be allowed during these 48 weeks, including the period immediately preceding study entry. 8. Patient willing and able to stop aspirin/ NSAIDS for 7 days before study entry and the scheduled skin biopsy procedures. 9. HIV-1 RNA \< 400 copies/mL for at least 90 days prior to study entry. 10. Laboratory values obtained within 60 days prior to study entry: 1. Absolute neutrophil count (ANC) ≥ 500 / mm3 2. Hemoglobin ≥ 9.0 g/dL 3. Platelet count ≥ 75,000/ mm3 4. Creatinine clearance \> 50 mL / min 5. PT/PTT \< 1.2 ULN Exclusion Criteria: 1. Receipt of AZT, d4T, ddI, or ddC at study entry or within 24 weeks of entry 2. Life expectancy \< 12 months 3. Women who are pregnant or breastfeeding 4. WOCBP unwilling to use contraception WOCBP who are unwilling or unable to use an acceptable method to avoid pregnancy for the entire study period 5. Women with a positive pregnancy test. 6. Sexually active fertile men not using effective birth control if their partners are WOCBP. 7. Other Exclusion Criteria 1. Prisoners or subjects who are involuntarily incarcerated. 2. Subjects who are compulsorily detained for treatment of either a psychiatric or physical (eg, infectious disease) illness. 8. Clinically important illness within 14 days prior to study entry 9. Inability to communicate effectively with the study personnel. 10. Bleeding diathesis 11. Supplementation with recombinant growth hormone, growth hormone releasing factor, anabolic steroids, estrogen or testosterone, unless it is for replacement purposes. 12. Have no plans to alter any vitamin supplementation that subjects are receiving at study entry. This includes all vitamin supplementation, coenzyme Q, N acetyl cysteine, L-acetyl carnitine, and uridine.