HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 (HIV-1) VIREMIA CHANGES AND DEVELOPMENT OF DRUG-RELATED MUTATIONS IN PATIENTS WITH SYMPTOMATIC HIV-1 INFECTION RECEIVING ALTERNATING OR SIMULTANEOUS ZIDOVUDINE AND DIDANOSINE THERAPY

The changes in viremia levels and the development of drug-related mutations were examined in 26 patients with symptomatic human immunodeficiency virus type 1 (HIV-1) infection participating in a randomized trial comparing alternating (A) and simultaneous (S) regimens of zidovudine and didanosine therapy, Patients on both arms had significant reduction in serum RNA copies from baseline throughout the 2 years of study, Significant differences between the two arms were demonstrated over the first 2-3 months of therapy, Analyses with nested polymerase chain reaction revealed that the emergence of the didanosine-related position 74 Leu-->Val mutation was significantly blocked in both regimens, while the zidovudine-related mutation at codon 215 was not affected. Determination of the overall durability of the antiviremic effect of the A and S regimens of zidovudine and didanosine and clinical implications of the results require further research.