Background: Acquired immunodeficiency syndrome can hardly be cured currently and
people with human immunodeficiency virus (HIV) need lifelong treatment that may result in the
emergence of drug resistance which leads to failed treatment. Thus, the development of new anti-
HIV drugs and new treatment regimens are necessary.
Objective: The aim of this study is to analyze the combined anti-HIV activity of tenofovir disoproxil
fumarate, lamivudine and ACC007, a new non-nucleoside reverse transcriptase inhibitor.
Methods: The antiviral activity of tenofovir disoproxil fumarate, lamivudine and ACC007 alone or
in combination against different HIV-1 strains was determined by the detection of HIV-1 p24 level
through enzyme-linked immunosorbent assay.
Result: ACC007 showed EC50 of nanomolar range (from 3.03 nM to 252.59 nM) against all HIV-1
strains used in this study except the HIV-1A17, with EC50 of 1.57 μM. The combined antiviral activity
of ACC007, lamivudine and tenofovir disoproxil fumarate showed synergy antiviral activity
against all HIV-1 strains used in this study. The three-drug combination showed moderate synergism
against HIV-1A17, HIV-14755-5, HIV-1K103N and HIV-1V106M, with a combination index value
ranging from 0.71 to 0.87, and showed synergism against the other HIV-1 strains with combination
index value from 0.35 to 0.67. The combination with ACC007 significantly increases the dose reduction
index value of lamivudine and tenofovir disoproxil fumarate, compared with two-drug
Conclusion: ACC007 exhibits potent antiviral activity alone or with 3TC and TDF, and exerts synergistic
effect against all HIV strains used in our investigation in vitro.