[AS PER AMENDMENT 8/25/97: Patients assigned to the monotherapy arm are advised to discontinue their study medication immediately and initiate antiretroviral therapy with indinavir, nevirapine, stavudine and 3TC, as outlined in ACTG 347 roll-over protocol, ACTG 373. Patients in the three-drug arm continue on study therapy.] [AS PER AMENDMENT 12/19/97: Patients receive study treatment for 56 weeks and are followed through week 68.]