Safety and Pharmacokinetic Study of Capravirine. Part I. Pharmacokinetics of Capravirine in HIV-Negative Volunteers. Part II. Antiviral Activity of Capravirine, Efavirenz, and Abacavir in HIV-Infected Patients

This 2-part study will test the safety and anti-HIV activity of capravirine alone, and the safety, anti-HIV activity, and drug interactions of capravirine combined with other anti-HIV drugs. Capravirine belongs to a class of drugs called non-nucleoside reverse transcriptase inhibitors (NNRTIs), which are effective when used together with other drugs, including nucleoside reverse transcriptase inhibitors (NRTIs) and protease inhibitors.

Normal volunteers 18 years of age and older may enroll in Part 1 of the study. HIV-infected patients 18 years of age and older who have not previously been treated with a NNRTI (efavirenz, nevirapine, and delavirdine) may participate in Part 2. All prospective study participants will be screened for eligibility with a physical examination, blood tests, a urine test and an electrocardiogram (ECG).

Part 1 - Volunteers will be randomly assigned to one of two treatment groups as follows:

Group 1 will receive capravirine alone for 7 days and capravirine plus efavirenz (another NNRTI) for an additional 10 days. On day 1, participants will have a physical examination, urine test and laboratory blood tests. Blood samples will be collected just before the first dose of capravirine is given and again at 0.5, 1, 2, 4, 6, 8 and 12 hours after the dose. A small plastic tube will be placed in a vein to avoid multiple needle sticks. On day 8, participants will have another physical examination and laboratory blood tests. Blood samples will be drawn again as described above. In the evening of day 8, efavirenz will be added to the regimen. On day 18 (the last day of the study), participants will have another physical examination and blood tests. Blood will again be collected as described above.

Group 2 will take capravirine alone for 8) days and capravirine plus ritonavir (a protease inhibitor) for an additional 8 days. Physical examinations, urine tests, and blood collections will be done as described above on day 1, day 8 and day 16 (the last day) of the study.

Part 2 - Patients will take capravirine alone for 7 days. On day 1, patients will have a physical examination, urine test and laboratory blood tests. Blood samples will be collected just before the first dose of capravirine is given and again at 0.5, 1, 2, 4, 6, 8 and 12 hours after the dose. A small plastic tube will be placed in a vein to avoid multiple needle sticks. On day 8, patients will have another physical examination and laboratory blood tests. Blood samples will be drawn again as described above. Additional drugs will then be added to the regimen (in varying doses according to group), as follows:

Group 1 - efavirenz plus abacavir

Group 2 - ritonavir plus efavirenz plus abacavir

Group 3 - ritonavir plus efavirenz plus abacavir

On day 15, the procedures performed on day 8 will be repeated.

Patients will have the option of having blood drawn daily on days 2 through 7 to measure HIV-1 viral load and of having a lumbar puncture (spinal tap) done between days 2 and 7 to measure how well capravirine gets into the central nervous system.

After day 15, patients in all groups will continue with their drug regimen until week 48 or until it is determined that the treatment is not effective for the patient. Physical examinations, viral load measurements, white blood cell counts and other blood tests will be done periodically throughout the trial. Within 4 weeks after the end of the study, patients will be followed with another physical examination, blood and urine tests, and an ECG.