Historical resistance profile helps to predict salvage failure.

BACKGROUND: This study compared the predictive value for treatment failure of extended resistance detected in the current genotype resistance test (GRT) versus those from GRT history in patients with multiple combination antiretroviral therapy (cART) failures. METHODS: Patients who underwent three GRT between 1999 and 2007 were included. Extended resistance at genotypic sensitivity score (GSS) using the Rega 7.1 interpretation system compared with a non-standard definition (defined as class-wide resistance [CWR] on the basis of International AIDS Society-USA mutations) was assessed both for current and historical GRTs (a combination of mutations was detected in all three tests). The predictive role of extended resistance for treatment failure was evaluated with an adjusted Cox proportional hazard model. RESULTS: Overall, 177 patients were included. The historical GRT increased the number of patients with extended resistance to all three major drug classes by 25% in comparison with the current GRT. Using the GSS method, the absence of detection of any active drug in any drug class was predictive of failure with both the current and historical GRTs. Similarly, the number of active drugs in the cART regimen after the third resistance test, used as continuous variable, was also predictive of failure. Using both GSS approaches, current genotype had a higher effect than historical genotype on risk of treatment failure. Using the non-standard definition (CWR), historical resistance predicted failure better than current resistance. CONCLUSIONS: Our results provide an epidemiological demonstration that analysis of a combined latest and historical GRT, which also considers archived mutations, might better identify of the more virologically impaired patients in order to assess the best salvage treatment.

Multiple drug class-wide resistance associated with poorer survival after treatment failure in a cohort of HIV-infected patients.

OBJECTIVE: To evaluate the effect of drug class-wide resistance (CWR) on survival in HIV-infected individuals who underwent genotypic resistance test after antiretroviral failure. DESIGN: Observational, longitudinal cohort study. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Cross-resistance among nonnucleoside reverse transcriptase inhibitors limits recycling efavirenz after nevirapine failure.

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 log(10) among patients carrying single NNRTI-associated mutations compared with -1.32 log(10) 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.