To compare the proportion of patients whose plasma HIV-1 RNA is below 500 copies/ml after 16 weeks of treatment. To assess the safety, toxicity, and tolerance of each treatment arm.

While indinavir is currently the most commonly prescribed protease inhibitor, the optimal therapy for a person on an indinavir-containing regimen who experiences a rebound in viral load or never experiences a decrease in viral load below 500 copies per milliliter is unknown. Current clinical practice for such patients typically involves empiric use of a combination of other protease inhibitors (saquinavir/nelfinavir or saquinavir/ritonavir) and at least 1 other antiretroviral agent to which the patient has had little or no prior exposure. This may involve the use of 1 or more reverse transcriptase inhibitors (RTIs) or nonnucleoside reverse transcriptase inhibitors (NNRTIs). This study attempts to formally evaluate some of these options in indinavir-experienced patients.

While indinavir is currently the most commonly prescribed protease inhibitor, the optimal therapy for a person on an indinavir-containing regimen who experiences a rebound in viral load or never experiences a decrease in viral load below 500 copies per milliliter is unknown. Current clinical practice for such patients typically involves empiric use of a combination of other protease inhibitors (saquinavir/nelfinavir or saquinavir/ritonavir) and at least 1 other antiretroviral agent to which the patient has had little or no prior exposure. This may involve the use of 1 or more reverse transcriptase inhibitors (RTIs) or nonnucleoside reverse transcriptase inhibitors (NNRTIs). This study attempts to formally evaluate some of these options in indinavir-experienced patients.

Patients are stratified by HIV RNA (2,000 - 20,000 copies/ml versus 20,000 - 200,000 copies/ml), and randomized to 1 of 6 treatment arms as follows:

Arm A: Saquinavir (SQV) plus ritonavir (RTV) plus delavirdine (DLV) plus adefovir dipivoxil placebo.

Arm B: SQV plus RTV plus DLV placebo plus adefovir dipivoxil. Arm C: SQV plus RTV plus DLV plus adefovir dipivoxil. Arm D: SQV plus nelfinavir (NFV) plus DLV plus adefovir dipivoxil placebo. Arm E: SQV plus NFV plus DLV placebo plus adefovir dipivoxil. Arm F: SQV plus NFV plus DLV plus adefovir dipivoxil. In addition to assigned study treatment patients receive an L-carnitine supplement.

Therapy is administered for 24 weeks. Patients who have an average HIV RNA value for Weeks 12 and 16 that is less than 5,000 copies or a least 1 log below their baseline value may continue their assigned study treatment for an additional 24 weeks. [AS PER AMENDMENT 3/30/98: Subjects with plasma HIV RNA greater than 5,000 copies/ml may elect to continue or discontinue study medications in the treatment extension and seek the best available treatment.] [AS PER AMENDMENT 06/11/98: The dose of adefovir dipivoxil is reduced at or after Week 16. Alternatively, patients may discontinue adefovir dipivoxil/placebo and substitute appropriate antiretroviral agent(s) or add appropriate antiretroviral agent(s) to their reduced-dose regimen. Also, at the discretion of the protocol chairperson, patients who have been on study for more than 16 weeks may substitute appropriate FDA-approved antiretroviral agent(s) for any study medication that must be discontinued because of toxicity. Addition of nonnucleoside reverse transcriptase inhibitors, protease inhibitors, or investigational agents is specifically excluded.]

Inclusion Criteria

Concurrent Medication:

Required:

• Chemoprophylaxis for Pneumocystis carinii pneumonia for all patients who have a CD4 cell count of equal or less than 200 cells/mm3.

Allowed:

• Topical and oral antifungal agents except ketoconazole and itraconazole.
• Treatment, maintenance or chemoprophylaxis with approved agents for opportunistic infections.
• Antibiotics.
• Systemic corticosteroids for 21 days or less for acute problems.
• Recombinant erythropoietin (rEPO) and granulocyte-colony stimulating factor (G-CSF, filgrastim).
• Regularly prescribed medications such as antipyretics, analgesics, allergy medications, antidepressants, sleep medications, oral contraceptives (not as a sole form of birth control), megestrol acetate, or testosterone.
• Alternative therapies, such as vitamins, acupuncture, and visualization techniques.
• [AS PER AMENDMENT 3/30/98: Calcium channel blockers may be used only with caution.]

Patients must have:

• HIV-1 infection documented by a licensed ELISA and confirmed by Western blot, HIV culture, HIV antigen, plasma HIV RNA, or a second antibody test other than ELISA.
• 2,000 to 200,000 HIV-1 RNA copies/ml as measured by any Roche-certified laboratory [AS

PER AMENDMENT 3/30/98:

• using the Roche Amplicor HIV-1 Monitor] within 30 days of study entry.
• Signed, informed consent from parent or legal guardian for patients less than 18 years of age.

Prior Medication: Required:

• More than 6 months cumulative indinavir therapy.
• Stable indinavir-containing antiretroviral regimen for at least 4 weeks [2 weeks AS PER AMENDMENT 3/30/98] prior to study entry.

Exclusion Criteria

Co-existing Condition:

Patients with the following conditions or symptoms are excluded:

• Any active infection requiring acute treatment within 30 days [21 days AS PER AMENDMENT 3/30/98] prior to study entry.
• Unexplained temperature greater than 38.5 degrees for any 7 consecutive days within 30 days prior to study entry.
• Malignancy, including Kaposi's sarcoma, that requires systemic chemotherapy.

Concurrent Medication:

Excluded:

• Non-protocol-specified immunomodulatory and/or antiretroviral agents.
• Systemic cytotoxic chemotherapy.
• Ketoconazole, itraconazole, rifampin, rifabutin, alprazolam, amiodarone, astemizole, bepridil, bupropion, cisapride, clorazepate, clozapine, diazepam, encainide, estazolam, flecainide, flurazepam, isotretinoin, meperidine, midazolam, piroxicam, propafenone, propoxyphene, quinidine, terfenadine, triazolam, zolpidem, phenytoin, phenobarbital, carbamazepine, and ergot alkaloids and [ AS PER AMENDMENT 3/30/98: dexamethasone, ergot derivatives, and pimozide].

Avoided:

• Herbal medications.

Prior Medication:

Excluded:

• At least 2 weeks or more total ritonavir and/or saquinavir (hard gelatin capsule).
• NNRTIs (nevirapine, delavirdine, DMP-266, etc.), saquinavir (soft gelatin capsule), nelfinavir, 141W94VX-478, and adefovir dipivoxil.
• Immunomodulator [systemic immunomodulator AS PER AMENDMENT 3/30/98] or investigational drug therapy within 30 days prior to entry.
• Active immunization within 30 days [21 days AS PER AMENDMENT 3/30/98] prior to entry.