This study allows patients who need a new anti-HIV treatment to take tenofovir disoproxil fumarate (tenofovir DF), an experimental drug. This study also looks at any side effects the drug causes.

HIV-1-infected patients who are currently receiving stable antiretroviral therapy add tenofovir DF to their regimen. Study participation lasts for approximately 48 weeks. Interested patients should contact their physicians.

Inclusion Criteria

You may be eligible for this study if you:

• Are HIV-positive.
• Have a viral load greater than or equal to 10,000 copies/ml.
• Have a CD4 count less than or equal to 50 cells/mm3, or have a CD4 count greater than 50 and no more than 200 cells/mm3 with an opportunistic (AIDS-related) infection within 90 days of study entry. (Patients with a CD4 count above 200 cells/mm3 may be considered depending on drug supply.)
• Are at least 18 years old.
• Agree to use barrier methods of birth control (such as condoms) while on the study and for 30 days afterward.
• Have a life expectancy of at least one year.

Exclusion Criteria

You will not be eligible for this study if you:

• Have a history of a serious kidney or bone disease.
• Have severe nausea, vomiting, or trouble taking medications by mouth.
• Are pregnant or breast-feeding.
• Abuse alcohol or other substances that your doctor thinks would interfere with taking this medicine.
• Are taking any medicines that interfere with kidney functions.