Phase II Study on the Antiviral Activity and Safety of BILR 355 BS in HIV-1 Infected, NNRTI-treated Patients

Inclusion Criteria:

1. Signed informed consent in accordance with GCP and local regulatory requireme nts prior to trial participation.
2. HIV-1 infected males or females >= 18 years of age.
3. History of NNRTI based HAART >= 8 weeks and at least one, but not more than 3 NNRTI-associated resistance mutations by current genotype
4. TPV/r or LPV/r susceptible
5. CD4+ T lymphocyte count >= 100 cells/?l.

7. HIV-1 viral load >= 2000 copies/mL at screening. 8. Karnofsky score >= 70 9. Based on the antiviral resistance profile of the patients virus, the investig ator must be able to construct a background HAART treatment regimen (OBR) such t hat the patient will receive 3 effective ARV drugs, in addition to his study med ication. 10. Acceptable screening laboratory values (Visit 1) that indicate adequate base line organ function. Laboratory values are considered to be acceptable if the fo llowing apply: Absolute neutrophil count (ANC) >750/mm3 Hemoglobin >= 10 g/dL Platelet count >99,000/mm3 AST, ALT , and alkaline phosphatase < 2.5xULN >= DAIDS Grade 1) Total bilirubin <2.5xULN Serum amylase <1.5xULN 11. Acceptable medical history, as assessed by the investigator, with chest x-ra y results and ECG within 1 year of study participation. 12. Willingness to abstain from ingesting substances which may alter plasma stud y drug levels by interaction with the cytochrome P450 system 13. A prior AIDS defining event, excluding mycobacterial and invasive fungal inf ections, is acceptable as long as it has resolved or the subject has been on sta ble treatment (e.g. opportunistic infection) for at least 12 weeks before screen ing (Visit 1). Note that prior oral thrush, candida esophagitis and cutaneous ca ndida is acceptable.

Exclusion Criteria:

1. The following resistance mutations demonstrated at any time prior to starting trial therapy: V106A and/or Y188L

2. Female patients of child-bearing potential who:

   have a positive serum pregnancy test at screening or during the study, are breast feeding, are planning to become pregnant, are not willing to use a barrier method of contraception.

3. Active Hepatitis B or C disease defined as HBsAg positive or HCV RNA positive with AST/ALT > DAIDS Grade 1
4. Acute/previous mycobacterial or invasive fungal infection requiring therapy o r prophylaxis with drugs interfering with or significantly affected by the cytoc hrome P450 system
5. Use of investigational medications within 30 days before study entry or durin g the trial.
6. Use of concomitant drugs that may significantly reduce plasma levels of the s tudy medications.
7. Use of immunomodulatory drugs within 30 days before study entry or during the trial (e.g. interferon, cyclosporin, hydroxyurea, interleukin 2).
8. Patients currently treated with systemic ant-cancer chemotherapy
9. Inability to adhere to the requirements of the protocol, including active sub stance abuse, as defined by the investigator.
10. In the opinion of the investigator, likely survival of less than 12 months b ecause of underlying disease.