• The primary outcome measures are changes in the mDNA/nDNA ratio at each visit with regard to the baseline visit. [ Time Frame: At 24 and 48 weeks with regard to the baseline visit ] [ Designated as safety issue: No ]
  

• Study of the efficacy of the therapy with Lopinavir/rtv (3 tablets every 12 h) + Nevirapine (1 tablet every 12 h) in the maintenance of viral suppression and immune recovery in patients on HAART therapy for more than 9 months [ Time Frame: At 12, 24, 36 and 48 weeks. ] [ Designated as safety issue: No ]
  
• and CV<50 copies/mL over at last 6 months [ Time Frame: At 12, 24, 36 and 48 weeks ] [ Designated as safety issue: No ]
  
• To determine whether the combination with Lopinavir/rtv +Nevirapine is efficacious in avoiding progression to lipoatrophy/lipodystrophy or else the reversal thereof [ Time Frame: At 24 and 48 weeks ] [ Designated as safety issue: No ]
  
• To study whether the combination with Lopinavir/rtv +Nevirapine makes it possible to control dyslipidemia associated with the use of Lopinavir/rtv on proving the "lipid-lowering" action of NVP [ Time Frame: At 12, 24, 36 and 48 weeks. ] [ Designated as safety issue: No ]
  
• To check whether the simplified combination with the standard dose of Lopinavir/rtv with NVP is sufficient to maintain suppression of viral replication. Pharmacokinetic studies (PK) would be performed to estimate this point [ Time Frame: At 12, 24, 36 and 48 weeks ] [ Designated as safety issue: No ]
  
• To evaluate the tolerance and safety of the combination of Lopinavir-rtv+Nevirapine . [ Time Frame: over 48 weeks of treatment ] [ Designated as safety issue: Yes ]
  
• To evaluate treatment adherence and patient quality of life (evaluated by means of the MOS_HIV questionnaire). [ Time Frame: At 12, 24, 36 and 48 weeks ] [ Designated as safety issue: No ]
  

At the moment it is known that mitochondrial toxicity is the main pathogenic mechanism of toxicity associated with nucleoside analogues, including lipoatrophy, which at facial level is a stigmatising factor for patients with HIV infection.

The primary outcome measure of the design of an "NTRI-sparing" bitherapy is to retard the onset of mitochondrial toxicity or reverse it, mainly with regard to the loss of subcutaneous fat or lipoatrophy.

Lopinavir/ritonavir and nevirapine are two antiretrovirals with different mutation patterns and with high antiviral potency. Their combination therefore guarantees antiviral success. The NEKA study endorses efficacy immunologically and virologically (Negredo E. et al, NRTI-sparing regimen. XIV International AIDS Conference. Barcelona 2002. LB PeB9021).

Similarly, the protective effect of nevirapine on lipid metabolism would counteract the negative impact attributed to lopinavir/ritonavir, reducing cardiovascular risk in these patients.

Inclusion Criteria:

1. Age >= 18 years.
2. HIV-1 infected patients.
3. Patients on HAART therapy with PIs or NNRTIs.
4. Patients with an undetectable viral load (<50/80 copies/mL) over the last 6 months (at least 2 determinations separated by 2 months).
5. Hepatic tests < 5 times the normal value.
6. Subject able to follow the treatment period.
7. Women may not be of fertile age (defined as at least one year from menopause or undergoing any surgical sterilisation technique), or must undertake to use a barrier contraceptive method during the study.
8. Signature of the informed consent

Exclusion Criteria:

1. Presence of opportunistic infections and/or recent tumours (< 6 months).
2. Suspicion of resistance or documented resistance to any of the investigational drugs.
3. Suspicion of possible bad adherence.
4. Pregnancy or breastfeeding; refusal to follow reliable contraception over the treatment period.
5. Known allergic hypersensitivity to any of the investigational drugs or any similar drug.
6. Patients participating in another clinical trial.