A Study of 141W94 Used Alone or in Combination With Zidovudine Plus 3TC in HIV-Infected Patients

Inclusion Criteria Concurrent Medication: Allowed: * Chemoprophylaxis for Pneumocystis carinii pneumonia is required for all patients who have a CD4 cell count \<= 200 cells/mm3. * Topical and/or oral antifungal agents, except for those listed in excluded medications. * Treatment, maintenance or chemoprophylaxis with approved agents for opportunistic infections as clinically indicated, unless listed in excluded medications. * All antibiotics as clinically indicated. * Systemic corticosteroid use for \<= 21 days for acute problems is permitted as medically indicated; chronic systemic corticosteroid use is not permitted. * Recombinant erythropoietin and granulocyte colony-stimulating factor as medically indicated. Regularly prescribed medications such as: * antipyretics, analgesics, allergy medications, antidepressants, sleep medications, oral contraceptives (a barrier method is also required for this study), megestrol acetate, testosterone or any other medications, as medically indicated. * Alternative therapies such as vitamins, acupuncture and visualization techniques are permitted (excluding herbal medications). NOTE: * Patients should report the use of these therapies; alternative therapies will be recorded. Patients must have: * HIV-1 infection as documented by ELISA and confirmed. * \>= 5,000 HIV-1 RNA copies/ml (within 30 days prior to study entry). * CD4 cell count \>= 50 cells/mm3 within 60 days prior to study entry. * Signed, informed consent for patients \< 18 years of age. Prior Medication: Required: * Patients must be on a stable antiretroviral regimen for 30 days prior to study screening and remain on the same regimen until entry. Exclusion Criteria Co-existing Condition: Patients with the following symptoms or conditions are excluded: * Any active infection requiring acute treatment within 14 days prior to entry. * A malignancy that requires systemic therapy other than minimal Kaposi's sarcoma. NOTE: * Patients with minimal Kaposi's sarcoma, defined as \<= 5 cutaneous lesions and no visceral disease or tumor-associated edema, will be allowed to enroll as long as they do not require systemic therapy for Kaposi's sarcoma. Patients with the following prior symptoms and conditions are excluded: * Inability to tolerate ZDV 500-600 mg daily if ZDV was administered previously. Intolerance to ZDV is defined as any grade toxicity that resulted in a dose reduction or termination of ZDV. Prior Medication: Excluded: * Any 3TC therapy prior to entry. * Any HIV-1 protease inhibitor therapy prior to study entry (e.g., saquinavir, ritonavir, indinavir, nelfinavir, 141W94). * Any immunomodulator therapy within 30 days prior to entry. * Active immunization within 30 days prior to entry. * Any antiretroviral therapy change within 30 days prior to study screening. 1\. Concurrent use of non-protocol specified antiretroviral agents; either investigational or licensed. * Immunomodulators that affect immunologic or virologic indices such as systemic corticosteroids, thalidomide, or cytokines. * Concomitant use of rifabutin and/or rifampin. * Investigational drugs other than 141W94/VX-478. * Systemic cytotoxic chemotherapy. * Oral astemizole (Hismanal), carbamazepine (Tegretol), dexamethasone (Decadron), ketoconazole (Nizoral), itraconazole (Sporanox), phenobarbital, phenytoin (Dilantin), terfenadine (Seldane), cisapride (Propulsid), triazolam (Halcion) and midazolam (Versed). * Herbal medications.