To evaluate the effect of drug class-wide resistance (CWR) on survival in HIV-infected individuals who underwent genotypic resistance test after antiretroviral failure. Observational, longitudinal cohort study. HIV-infected individuals experiencing treatment failure were enrolled at first genotypic resistance test. End-points were death for any cause, AIDS-related death and AIDS-defining event/death. CWR was defined according to the International AIDS Society consensus. Survival analysis was performed with Cox's model. Among 623 patients enrolled and followed for a median of 19 months (interquartile range, 12–29), Kaplan–Meier analyses for end-points at 48 months in patients with no CWR, one CWR, two CWR or three CWR were 8.9, 11.7, 13.4 and 27.1%, respectively, for death; 6.1, 9.9, 13.4 and 21.5%, respectively, for AIDS-related death; and 16.0, 17.7, 19.3 and 35.9%, respectively, for new AIDS event/death. In a multivariate Cox's model, higher HIV RNA level, previous AIDS and detection of three CWR (hazard ratio, 5.34; 95% confidence interval, 1.76–16.24) were all significantly associated with increased risk of death, while higher CD4 cell count and use of a new boosted protease inhibitor drug after identifying genotypic resistance were associated with reduced risk. Detection of three CWR was also significantly associated with higher risk of AIDS-related death and new AIDS event/death. Even in the late era of highly effective antiretroviral treatments, detection of CWR, particularly if extended to all three drug classes is related to poorer clinical outcome and represents a risk-marker of disease progression and death.

Heterogeneity in genotype mutations associated with resistance of HIV to nonnucleoside reverse transcriptase inhibitors (NNRTIs) should allow identification of patients failing nevirapine (NVP) who might benefit from efavirenz (EFV)-containing salvage regimens. To establish the feasibility of recycling EFV after failure of NVP-containing regimens genotypic data on 103 NVP-failed patients were analyzed to evaluate the prevalence of EFV resistance-conferring mutations. A clinically significant resistance to EFV was found in 50 of 103 (58%) of NVP-failed subjects. Furthermore, the 3-month virological response to salvage regimens containing EFV was assessed in patients previously treated with NVP and carrying single mutations conferring resistance to this drug. A proportion of HIV RNA less than 500 copies/ml at 3 months was obtained only in 2 of 12 (17%) of EFV-treated subjects compared with 35 of 67 (52%) of those without NNRTI mutations (OR, 0.18; 95% CI, 0.03-0.79). The median HIV-1 RNA decrease after 3 months was -0.63 log₁₀ among patients carrying single NNRTI-associated mutations compared with -1.32 log₁₀ among those without any NNRTI mutations. No virological response was observed in six patients harboring a single Y181C/I mutation. On the basis of the present data, sequential use of NNRTIs should be avoided in the management of treatment failure.

Background. Cerebrospinal fluid (CSF) concentrations of multiple drugs in a large human immunodeficiency virus (HIV)—infected patient population, the virtual ph

The role of mutations in protease (PR) and reverse-transcriptase (RT) of human immunodeficiency virus (HIV) in predicting virologic failure was asses

Background. We evaluated reliability and clinical usefulness of genotypic resistance testing (GRT) in patients for whom combination antiretroviral therapy (cART) was unsuccessful with viremia levels 50–1000 copies/mL, for whom GRT is generally not recommended by current guidelines.

Resistance to antivirals is a complex and dynamic phenomenon that involves more mutations than are currently known. Here, we characterize 10 additional mutations (L74V, K101Q, I135M/T, V179I, H221Y, K223E/Q, and L228H/R) in human immunodeficiency virus type 1 (HIV-1) reverse transcriptase which are involved in the regulation of resistance to nonnucleoside reverse transcriptase inhibitors (NNRTIs). These mutations are strongly associated with NNRTI failure and strongly correlate with the classical NNRTI resistance mutations in a data set of 1,904 HIV-1 B-subtypepolsequences from 758 drug-naïve patients, 592 nucleoside reverse transcriptase inhibitor (NRTI)-treated but NNRTI-naïve patients, and 554 patients treated with both NRTIs and NNRTIs. In particular, L74V and H221Y, positively correlated with Y181C, were associated with an increase in Y181C-mediated resistance to nevirapine, while I135M/T mutations, positively correlated with K103N, were associated with an increase in K103N-mediated resistance to efavirenz. In addition, the presence of the I135T polymorphism in NNRTI-naïve patients significantly correlated with the appearance of K103N in cases of NNRTI failure, suggesting that I135T may represent a crucial determinant of NNRTI resistance evolution. Molecular dynamics simulations show that I135T can contribute to the stabilization of the K103N-induced closure of the NNRTI binding pocket by reducing the distance and increasing the number of hydrogen bonds between 103N and 188Y. H221Y also showed negative correlations with type 2 thymidine analogue mutations (TAM2s); its copresence with the TAM2s was associated with a higher level of zidovudine susceptibility. Our study reinforces the complexity of NNRTI resistance and the significant interplay between NRTI- and NNRTI-selected mutations. Mutations beyond those currently known to confer resistance should be considered for a better prediction of clinical response to reverse transcriptase inhibitors and for the development of more efficient new-generation NNRTIs.