It has been impossible to achieve the number of patients defined by protocol

In retrospective studies, acceleration of hepatic fibrosis has been seen in Nevirapine (NVP) treatment when compared with Protease Inhibitors (PI) boosted with ritonavir treatment in patients with Human Immunodeficiency Virus (HIV) and Hepatitis C Virus (HCV) infection. The high incidence in our country of HIV-HCV co-infection, the availability of a new Kaletra (LPV/r) formulation (more convenient and better tolerated than soft capsules) as well as the possibility of analyzing hepatic fibrosis evolution in a fast and bloodless way, make attractive a study that, in a prospective way, could check the benefits of substituting NVP by LPV/r on hepatic fibrosis in this community.

The prevalence of the HIV-HCV co-infection in Spain is one of the highest because both infections are strongly related to parenteral drugs use; so, from 61 to 69 % of HIV infected patients are also HCV infected.

Acute HCV infection is asymptomatic in 60 to 70% of cases, being the chronification the natural illness evolution. 20% of the patients will develop hepatic cirrhosis after 20 to 30 years of being infected by the HCV. In cirrhosis cases, the hepatocellular carcinoma appears in a rate of 2 to 4% per year, according to studies done with HCV mono-infected patients. Fibrosis progression depends basically on the duration of HCV infection and on the age of infection, but also on other factors, like gender (is faster in men), alcohol consumption (worst over 50 g per day) and HIV co-infection. Several epidemiologist studies have described the negative impact of HIV co-infection, accelerating the progression to cirrhosis and the hepatocarcinoma.

The Highly Active Antiretroviral Treatment (HAART) has a positive impact on survival on co-infected patients, although the three drug families used in HAART can cause hepatic toxicity in this group of patients. Hepatic toxicity appears in 5 to 20% of patients, being more serious and common, but not exclusive, in case of NVP treatment.

On their part, not all PI have the same hepatotoxic profile. An association between serious hepatotoxicity and ritonavir at full strength, indinavir and indinavir plus saquinavir boosted with ritonavir has been found.

As far as fibrosis is concerned, there are studies that show that in HIV/HCV co-infected patients PI-based regimens are associated with a lower progression to fibrosis, while the progression rate to cirrhosis is higher in NVP-based regimens, mainly in those patients with advanced hepatic fibrosis.

Hepatic biopsy is considered the reference test to assess hepatic fibrosis, nevertheless it is an invasive, painful and with a low but potentially serious risk for the patient's life. Moreover, the viability of a hepatic biopsy can be doubted due to sampling error or interobservation variability. For that reason, several biochemist tests have been developed to reflect the hepatic fibrosis extent or stage in a reliable way. Recently a hepatic rigidity measure through elastography has been presented as a non-invasive and very promising method to assess hepatic fibrosis.

Inclusion Criteria:

1. 18 years old or elder.
2. HCV and HIV co-infected patients.
3. Patients with antiretroviral treatment based in NVP plus 2 NRTIs (or 1 NRTI and Tenofovir), with undetectable viral load (under 50 copies/mL) during at least the last 24 weeks.
4. If women and of childbearing age, negative pregnancy test. Furthermore, barrier contraceptive method must be undertaken during the study.
5. Date and signature of the informed consent.

Exclusion Criteria:

1. Concomitant treatment with drugs that can significantly interact with the study drugs.
2. Opportunistic infections in the last 6 months.
3. Patients who can be candidates for an HCV infection treatment in the next 3 years.
4. Patients in who efficacy of previous NRTIs can not be ensured. For example, patients with mono or dual therapy history or with previous blips in whom NRTI-related mutations were identified that could reduce the sensibility to the used backbone.
5. Active alcohol consumption (over 50 g per day) or other substance abuse.
6. Pregnant or breastfeeding women.
7. Patients with transaminase level over 5 times the Upper Limit of Normality (ULN) or Creatinin over 2 mg/dL or Total Bilirubin over 3 times the ULN.
8. Any formal contraindication for being treated with the study drugs.
9. Patients who, basing in their antiretroviral treatment history, could be considered as being infected with a virus that has no sensibility to LPV.