AMENDED: Effective with Version 4 (900226), dosing for ALL patients on Phase 2 study drug, regardless of CD4+ substudy, will proceed as open-label AZT. Original treatment assignments employed in the > 500 cells/mm3 substudy during the period from August 16, 1989 through the release of this new version. Also, toxicity management and dose modification of AZT for patients receiving Phase 2 study drug have been changed.