Ninety-six patients (four treatment arms of 24 patients each) are randomized to receive oral Ro 24-7429 at 1 of 3 doses or nucleoside control (either zidovudine or didanosine). The study will be blinded only for the arms receiving Ro 24-7429. Treatment continues for 12 weeks. After 12 weeks, patients on the nucleoside control arm receive the highest tolerated dose of Ro 24-7429 in addition to their nucleoside.