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Objectives: To evaluate the prevalence and therapeutic relevance of drug resistance among isolates from ART-experienced HIV-1-infected patients over the past two decades in Italy.Methods: Dynamics of resistance to one, two and three or more antiretroviral classes were evaluated from 1999-2018. Virological success (VS) after the latest therapy switch was evaluated according to cumulative class resistance and cumulative genotypic susceptibility score (Stanford HIV_DB algorithm).Results: Among 13 663 isolates (from 6739 patients), resistance to at least one drug class decreased sharply from 1999 to 2010 (≤2001, 84.6%; 2010, 43.6%; P < 0.001), then remained relatively constant at ∼40% during 2010-18, with the proportion of resistance to three or more classes also stable (∼5%). After 2008, integrase inhibitor resistance slightly increased from 5.6% to 9.7% in 2018 and contributed to resistance, particularly in isolates with resistance to three or more classes (one class, 8.4%; two classes, 15.3%; three or more classes, 34.7%, P < 0.001). Among 1827 failing patients with an available follow-up, by 1 year after genotype-guided therapy start the probability of VS was 87.6%. Patients with cumulative resistance to three or more classes and receiving a poorly active regimen showed the lowest probability (62.6%) of VS (P < 0.001) compared with all other patients (≥81.8%). By Cox regression analysis, cumulative MDR and receiving poorly active antiretroviral regimens were associated with a lower hazard of VS compared with those without resistance.Conclusions: A dramatic drop of HIV-1 drug resistance at failure has been achieved over the last two decades in Italy; resistance to three or more classes is low but present among currently failing patients. Its management still requires a rational and careful diagnostic and therapeutic approach. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the maintenance of virological suppression (VS) in antiretroviral-treated HIV-1-suppressed patients switching to a tenofovir/emtricitabine/rilpivirine (TDF/FTC/RPV) single-tablet regimen, by considering pre-existent resistance (pRes).Methods: pRes was evaluated according to resistance on all previous plasma genotypic resistance tests. Probability and predictors of virological rebound (VR) were evaluated.Results: Three hundred and nine patients were analysed; 5.8% of them showed resistance to both NRTIs and NNRTIs, while 12.6% showed resistance to only one of these drug classes. By 72 weeks, the probability of VR was 11.3%. A higher probability of VR was found in the following groups: (i) patients with NRTI + NNRTI pRes compared with those harbouring NRTI or NNRTI pRes and with those without reverse transcriptase inhibitor pRes (39.2% versus 11.5% versus 9.4%, P  <   0.0001); (ii) patients with a virus with full/intermediate resistance to both tenofovir/emtricitabine and rilpivirine compared with those having a virus with full/intermediate resistance to tenofovir/emtricitabine or rilpivirine and those having a virus fully susceptible to TDF/FTC/RPV (36.4% versus 17.8% versus 9.7%, P  <   0.001); and (iii) patients with pre-therapy viraemia >500 000 copies/mL compared with those with lower viraemia levels (>500 000: 16.0%; 100 000-500 000: 9.3%; <100 000 copies/mL: 4.8%, P  =   0.009). pRes and pre-therapy viraemia >500 000 copies/mL were independent predictors of VR by multivariable Cox regression.Conclusions: TDF/FTC/RPV as a treatment simplification strategy shows a very high rate of VS maintenance. The presence of pRes to both NRTIs and NNRTIs and a pre-therapy viraemia >500 000 copies/mL are associated with an increased risk of VR, highlighting the need for an accurate selection of patients before simplification. [ABSTRACT FROM AUTHOR]

Objectives: To define the impact of coinfection with hepatitis B virus (HBV) or hepatitis C virus (HCV) on viroimmunological response to raltegravir-based salvage regimens that also include new HIV inhibitors such as maraviroc, darunavir and etravirine.Methods: We used data from a national observational study of patients starting raltegravir-based regimens to compare virological suppression and CD4 cell change from baseline in patients with and without concomitant HBV or HCV infection.Results: Overall, 275 patients (107 coinfected and 168 non-coinfected) were evaluated. Coinfected patients were more commonly former intravenous drug users and had a longer history of HIV infection and higher baseline aminotransferase levels. Both HIV-RNA and CD4 response were similar in the two groups. Mean time to first HIV-RNA copy number <50 copies/mL was 4.1 months (95% CI 3.5-4.6) in non-coinfected patients and 3.9 months (95% CI 3.3-4.5) in coinfected patients (hazard ratio 1.039, 95% CI 0.761-1.418, P = 0.766, log-rank test). The risk of developing new grade 3-4 hepatic adverse events was significantly higher in coinfected patients (hazard ratio 1.779, 95% CI 1.123-2.817, P = 0.009). The two groups of coinfected and non-coinfected patients had similar rates of interruption of any baseline drug (hazard ratio 1.075, 95% CI 0.649-1.781, P = 0.776) and of raltegravir (hazard ratio 1.520, 95% CI 0.671-3.447, P = 0.311). Few AIDS-defining events and deaths occurred.Conclusions: Viroimmunological response to regimens based on raltegravir and other recent anti-HIV inhibitors is not negatively affected by coinfection with HBV or HCV. Liver toxicity, either pre-existing or new, is more common in coinfected patients, but with no increased risk of treatment interruption. [ABSTRACT FROM AUTHOR]