Inhibition of human immunodeficiency virus type 1 infection in vitro by combination of delavirdine, zidovudine and didanosine

Delavirdine (DLV), a non-nucleoside reverse transcriptase inhibitor (RTI) of human immunodeficiency virus type 1 (HIV-1), was evaluated in two and three-drug combinations against acute and co-culture infections of HIV-1 JRCSF in human peripheral blood mononuclear cells. DLV combined with didanosine (DDI) at 1:10 and 1:30 ratios were statistically synergistic (combination indices (CI)75% inhibition levels. However, at 1:100 ratio, the interaction appeared to be additive. Three-drug combinations of zidovudine (ZDV), DLV, and DDI (at a ratio of 1:2:333) were synergistic at 50–99% inhibition levels. The three-drug group also showed significantly ( P