The demise of multidrug-resistant HIV-1: the national time trend in Portugal

Trends and predictors of HIV-1 acquired drug resistance in Minas Gerais, Brazil: 2002-2012

Several studies show that the prevalence of multidrug-resistant HIV-1 virus is declining over time. A retrospective cohort study was carried out to evaluate the trends of drug resistance in antiretroviral treatment-exposed individuals in a state of a middle-income country, Minas Gerais, southeast region of Brazil. We analyzed 2115 HIV-1 sequences from 2002 up to 2012, from 52 cities of Minas Gerais. The groups were analyzed according to the definitions: "IAS - 3 class mutations", if ≥1 drug resistance mutation from IAS 2015 list (DRM) was present in each class; "No fully susceptible drugs" as the absence of any fully susceptible drug in Stanford algorithm; and "GSS≥2″, when a maximum calculated GSS (genotypic susceptibility score) was ≥2 or ≥3, counting only drugs available in Brazil and USA at given calendar years. Time trends of resistance were analyzed by Cochran-Armitage test. We observed a decrease in the rate resistance mutations for PI, NRTI, "IAS - 3 class mutations", and "No fully susceptible drugs" over these 11 years, from 69.2% to 20.7%, 92.3% to 90.2%, 46.2% to 22.5%, and 12.8% to 5.7%, respectively (p<0.05). Resistance to NNRTI increased from 74.4% to 81.6%, mainly because of K103N mutation. The GSS score ≥2 increased during the years from 35.9% to 87.3% (p<0.001). We demonstrate that resistance to PI and to the three main classes simultaneously are declining, although the number of patients on of antiretroviral therapy has doubled in the last ten years in Brazil (125,000 in 2002 to 400,000 in 2014). Broader resistance testing and the availability of more therapeutic options might have influenced this decline. The increase in NNRTI resistance can limit this class as first line treatment in Brazil in the future.

Trends in drug resistance-associated mutations in a real-life cohort of Italian patients infected with HIV-1

Recent studies support the idea that human immunodeficiency virus type 1 (HIV-1) drug resistance is declining in developed countries. To help assess the current situation in Italy, the dynamics of drug resistance mutations in pol and integrase genes in plasma samples from HIV-1-positive patients attending Sapienza University Hospital, Rome, from 2003 to 2014 were analysed. In total, 1730 genotype resistance tests (GRTs) were retrospectively analysed. The prevalence of major drug resistance mutations (DRMs) was evaluated over time in the global population and in patients with antiretroviral therapy (ART) failure. Population dynamics, changes in ART administration, and HIV-1 RNA levels were analysed in combination with DRM trends. The global population showed a strong reduction in major DRMs to all drug classes. Over the 2003-2014 decade, resistance to nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs) and protease inhibitors (PIs) declined from 80.0% to 18.7%, from 42.8% to 20.1% and from 74.2% to 8.3%, respectively (P<0.005 for all comparisons). However, only PI-associated mutations showed a significant decrease in patients experiencing ART failure. Interestingly, analysis of the integrase gene disclosed an increased resistance to integrase inhibitors, mainly regarding N155H, detected in 32.6% of raltegravir-treated patients in 2012-2014. In conclusion, in line with previous findings, this study shows that drug resistance is declining in Italy. However, the persistence of DRMs to NRTIs and NNRTIs suggests that despite adherence and treatment optimisation, some patients still experience therapy failure, emphasising the need for GRTs both in naïve and ART-failed patients.

Profile of the HIV epidemic in Cape Verde: molecular epidemiology and drug resistance mutations among HIV-1 and HIV-2 infected patients from distinct islands of the archipelago

HIV-1 and HIV-2 have been detected in Cape Verde since 1987, but little is known regarding the genetic diversity of these viruses in this archipelago, located near the West African coast. In this study, we characterized the molecular epidemiology of HIV-1 and HIV-2 and described the occurrence of drug resistance mutations (DRM) among antiretroviral therapy naïve (ARTn) patients and patients under treatment (ARTexp) from different Cape Verde islands. Blood samples, socio-demographic and clinical-laboratory data were obtained from 221 HIV-positive individuals during 2010–2011. Phylogenetic and bootscan analyses of the pol region (1300 bp) were performed for viral subtyping. HIV-1 and HIV-2 DRM were evaluated for ARTn and ARTexp patients using the Stanford HIV Database and HIV-GRADE e.V. Algorithm Homepage, respectively. Among the 221 patients (169 [76.5%] HIV-1, 43 [19.5%] HIV-2 and 9 [4.1%] HIV-1/HIV-2 co-infections), 67% were female. The median ages were 34 (IQR = 1–75) and 47 (IQR = 12–84) for HIV-1 and HIV-2, respectively. HIV-1 infections were due to subtypes G (36.6%), CRF02_AG (30.6%), F1 (9.7%), URFs (10.4%), B (5.2%), CRF05_DF (3.0%), C (2.2%), CRF06_cpx (0.7%), CRF25_cpx (0.7%) and CRF49_cpx (0.7%), whereas all HIV-2 infections belonged to group A. Transmitted DRM (TDRM) was observed in 3.4% (2/58) of ARTn HIV-1-infected patients (1.7% NRTI, 1.7% NNRTI), but not among those with HIV-2. Among ARTexp patients, DRM was observed in 47.8% (33/69) of HIV-1 (37.7% NRTI, 37.7% NNRTI, 7.4% PI, 33.3% for two classes) and 17.6% (3/17) of HIV-2-infections (17.6% NRTI, 11.8% PI, 11.8% both). This study indicates that Cape Verde has a complex and unique HIV-1 molecular epidemiological scenario dominated by HIV-1 subtypes G, CRF02_AG and F1 and HIV-2 subtype A. The occurrence of TDRM and the relatively high level of DRM among treated patients are of concern. Continuous monitoring of patients on ART, including genotyping, are public policies to be implemented.

Recent trends in HIV-1 drug resistance

Once considered an inevitable consequence of HIV treatment, drug resistance is declining. This decline supports the hypothesis that antiretroviral therapy can arrest replication and prevent the evolution of resistance. Further support comes from excellent clinical outcomes, the failure of treatment intensification to reduce residual viremia, the lack of viral evolution in patients on optimal therapy, pharmacodynamics studies explaining the extraordinarily high antiviral activity of modern regimens, and recent reports of potential cures. Evidence supporting ongoing replication includes higher rates of certain complications in treated patients and an increase in circular forms of the viral genome after intensification with integrase inhibitors. Recent studies also provide an explanation for the observation that some patients fail protease-inhibitor based regimens without evidence for resistance.