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The amino acid position 70 in HIV-1 reverse transcriptase (RT) plays an important role in nucleoside RT inhibitor (NRTI) resistance. K70R is part of the thymidine analog mutations, but also other amino acid changes have been associated with NRTI resistance, such as K70E and K70G. In this study, we investigated the in vivo selection of the HIV-1 RT mutations K70S and K70T and their in vitro effect on drug resistance and replication capacity.Recombinant viruses with RT mutations were generated to measure the in vitro drug susceptibility and replication capacity. Bayesian network analysis and three-dimensional modeling were performed to understand the selection and impact of the RT70 mutations.K70S and K70T were found at a low frequency in RTI-experienced HIV-1 patients (0.10% and 0·20%). Baeyesian network learning identified no direct association with the in vivo exposure to any specific RTI. However, direct associations of K70S with mutations within the Q151M-complex and of K70T with K65R were observed. In vitro phenotypic testing revealed only minor effects of K70R/S/T as single mutations, associated with Q151M and within the context of the Q151M-complex.These results suggest that the selection of K70S/T and their phenotypic impact are influenced by the presence of other mutations in RT. However, the low impact on in vitro phenotype here observed, alongside with the low in vivo prevalence, the exclusive direct association with known major RTI mutations and the unknown correlation with in vivo response, do not yet necessitate the inclusion of K70S/T in drug resistance interpretation systems.

Genotypic drug resistance testing is routine practice in HIV-1 clinical care. The visual interpretation of sequencing electropherograms is labour-intensive and subject to intra- and inter-assay variability because decisions are based on operators' judgments. In this study the performance of the automatic editing tool RECall was compared to the current standard of editing manually and editing using the tool ViroSeq. Using RECall a consensus sequence could be generated for 97% of the V3 loop and for 79% of the pol experiments. By comparison, using manual editing a consensus sequence could be reached for 87% of the V3 and 87% of the pol experiments. Using ViroSeq, a consensus sequence was generated for 68% of the pol experiments. On a predefined dataset, manual editing displayed the highest probability to accurately assign mixtures (0.91 vs. 0.88 by ViroSeq vs. 0.76 by RECall) and the lowest probability to inaccurately assign a mixture to a pure base call (0.002 vs. 0.019 by ViroSeq vs. 0.002 by RECall). As differences in base calling have little impact on drug resistance interpretation and hands-on-time could be substantially reduced, RECall could be a valuable tool for the standardization and acceleration of the editing process.

In Cuba, antiretroviral therapy rollout started in 2001 and antiretroviral therapy coverage has reached almost 40% since then. The objectives of this study were therefore to analyze subtype distribution, and level and patterns of drug resistance in therapy-naive HIV-1 patients. Four hundred and one plasma samples were collected from HIV-1 therapy-naive patients in 2003 and in 2007–2011. HIV-1 drug resistance genotyping was performed in the pol gene and drug resistance was interpreted according to the WHO surveillance drug-resistance mutations list, version 2009. Potential impact on first-line therapy response was estimated using genotypic drug resistance interpretation systems HIVdb version 6.2.0 and Rega version 8.0.2. Phylogenetic analysis was performed using Neighbor-Joining. The majority of patients were male (84.5%), men who have sex with men (78.1%) and from Havana City (73.6%). Subtype B was the most prevalent subtype (39.3%), followed by CRF20-23-24_BG (19.5%), CRF19_cpx (18.0%) and CRF18_cpx (10.3%). Overall, 29 patients (7.2%) had evidence of drug resistance, with 4.0% (CI 1.6% – 4.8%) in 2003 versus 12.5% (CI 7.2% – 14.5%) in 2007–2011. A significant increase in drug resistance was observed in recently HIV-1 diagnosed patients, i.e. 14.8% (CI 8.0% – 17.0%) in 2007–2011 versus 3.8% (CI 0.9% – 4.7%) in 2003 (OR 3.9, CI 1.5 – 17.0, p = 0.02). The majority of drug resistance was restricted to a single drug class (75.8%), with 55.2% patients displaying nucleoside reverse transcriptase inhibitor (NRTI), 10.3% non-NRTI (NNRTI) and 10.3% protease inhibitor (PI) resistance mutations. Respectively, 20.7% and 3.4% patients carried viruses containing drug resistance mutations against NRTI + NNRTI and NRTI + NNRTI + PI. The first cases of resistance towards other drug classes than NRTI were only detected from 2008 onwards. The most frequent resistance mutations were T215Y/rev (44.8%), M41L (31.0%), M184V (17.2%) and K103N (13.8%). The median genotypic susceptibility score for the commonly prescribed first-line therapies was 2.5. This analysis emphasizes the need to perform additional surveillance studies to accurately assess the level of transmitted drug resistance in Cuba, as the extent of drug resistance might jeopardize effectiveness of first-line regimens prescribed in Cuba and might necessitate the implementation of baseline drug resistance testing.

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a b s t r a c t Background: Emergence of HIV-1 drug resistance may limit the sustained benefits of antiretroviral therapy (ART) in settings with limited laboratory monitoring and drug options. Objectives: Surveillance of drug resistance and subtypes in HIV-1 patients failing ART in Cuba. Study design: This study compiled data of ART-experienced HIV-1 patients attending a clinical center in Havana in 2003 and 2009-2011. The first period included results of a cross-sectional study, whereas in the second period genotyping was performed as part of routine care. Drug resistance mutations and levels were determined using HIVdb version 6.0.9. Results: Seventy-six percent received solely ART containing at least 3 drugs, of which 79.1% ever receiving unboosted protease inhibitors (PI). Patients from 2009 to 2011 were longer treated and exposed to more ART regimens. Subtype B (39%) and CRF19 cpx (18%) were the most prevalent genetic forms. Subtype distribution did not change significantly between both periods, except for BG recombinants that increased from 6% to 14%. Nucleoside reverse transcriptase inhibitor (NRTI), non-nucleoside RTI (NNRTI) and PI mutations were present in 69.5%, 54.8% and 44.4%. Full-class resistance (FCR) to NRTI, NNRTI, PI and multidrug resistance (MDR) were detected in 31.8%, 37.9%, 18.5% and 15.4%. FCR to NRTI, NNRTI, PI and MDR were present in 9.8%, 14.1%, 0%, 0% after first-line failure and in 19.8%, 20.8%, 2.9% and 2.9% after second-line failure. Conclusions: Our study found a high prevalence of drug resistance and supports the need for appropriate laboratory monitoring in clinical practice and access to drug options in case of virological failure.

Introduction : Emergence of HIV-1 drug resistance may limit the sustained benefits of antiretroviral therapy (ART) in settings with limited laboratory monitoring and drug options. The objective is to implement the surveillance of drug resistance and subtypes in HIV-1 patients failing ART in Cuba. Methods : This study compiled clinical and genotypic drug resistance data 588 ART-experienced HIV-1 patients attending a clinical center in Havana in 2009–2013. Drug resistance testing was performed as part of routine clinical care. Drug resistance mutations and levels were determined using Rega version 8.0.2. Results : Eighty-three percent received solely ART containing at least three drugs. Patients from 2009 to 2010 were longer treated (median: 4.9 vs 2.7 years) and exposed to more ART regimens (median: 4 vs 2 regimens) compared to patients from 2011–2013. Nucleoside reverse transcriptase inhibitor (NRTI), non-nucleoside RTI (NNRTI) and PI mutations were present in 83.5, 77.4 and 52.0%. Full-class resistance (FCR) to NRTI, NNRTI, PI and multidrug resistance (MDR) were detected in 25.0, 33.7, 11.4 and 6.3%. FCR to NRTI, NNRTI, PI and MDR were present in 12.8, 28.7, 0 and 0% after first-line failure (164 patients) and in 23.1, 34.6, 3.8 and 3.1% after second-line failure (130 patients). Subtype B (32.5%), BG recombinants (19.6%) and CRF19_cpx (16.2%) were the most prevalent genetic forms. Subtype distribution did not change significantly between 2009–2010 and 2011–2013, except for BG recombinants that increased from 12.2 to 21.3% (p=0.002). Conclusions : Our study found a high prevalence of drug resistance and supports the need for appropriate laboratory monitoring in clinical practice and access to drug options in case of virological failure. (Published: 2 November 2014) Citation: Abstracts of the HIV Drug Therapy Glasgow Congress 2014 Kouri V et al. Journal of the International AIDS Society 2014, 17(Suppl 3) :19754 http://www.jiasociety.org/index.php/jias/article/view/19754 | http://dx.doi.org/10.7448/IAS.17.4.19754