Patients (10 per dose level) are randomized to receive 1 of 4 doses of 935U83 every 8 hours for 12 weeks. Five patients at each dose level must complete 4 weeks of treatment without serious toxicity before subsequent patients are entered at the next higher dose. If lack of antiretroviral effect or unacceptable toxicity is demonstrated at a particular dose level, the dose regimens may be adjusted.