A Comparison of Zidovudine (AZT) and Stavudine in HIV-Infected Patients

Inclusion Criteria Concurrent Medication: Allowed: * AZT. Patients must have: * Documented HIV infection as determined by a positive ELISA and/or Western blot. * Absolute CD4 count of 100 - 500 cells/mm3 within 90 days prior to registration OR a CD4 count of 50 - 99 cells/mm3 within 30 days prior to registration. * Prior zidovudine therapy for at least 6 months and currently tolerating at least 500 mg daily. Exclusion Criteria Co-existing Condition: Patients with the following symptoms and conditions are excluded: * Newly diagnosed AIDS-defining opportunistic infection requiring acute therapy at time of enrollment. * Need for chronic systemic therapy at time of enrollment. * Intractable diarrhea. * Signs or symptoms of bilateral peripheral neuropathy at time of screening. * Demonstrated intolerance to zidovudine therapy. * Any other clinical conditions that would render the patient unsuitable for study or unable to comply with the dosing requirements. Concurrent Medication: Excluded: * Chronic systemic therapy with agents likely to suppress bone marrow, cause neurotoxicity, or create hepatic dysfunction. Patients with the following prior conditions are excluded: * Prior history of bilateral peripheral neuropathy. * Demonstrated intolerance to zidovudine therapy. Prior Medication: Excluded: * Prior d4T, ddI, or ddC. * Other investigational antiretroviral drugs (e.g., AZddU, Al 721, interferon, or immunomodulating drugs within 1 month prior to study entry or ribavirin within 3 months prior to study entry). * Prior myelosuppressive, neurotoxic, or cytotoxic anticancer therapy within 3 months prior to study entry. * Any prior therapy that would render the patient unsuitable for study or unable to comply with dosing requirements. Required: * At least 6 months of prior AZT and currently tolerating at least 500 mg daily, with the last dose received no more than 7 days prior to study entry.