Tenofovir resistance in early and long-term treated patients on first-line antiretroviral therapy in eight low-income and middle-income countries.

OBJECTIVE: We aimed to assess the frequency of tenofovir (TDF) resistance in people failing tenofovir/lamivudine or emtricitabine (XTC)/nonnucleotide reverse-transcriptase inhibitor-based first-line antiretroviral treatment (ART) using data from 15 nationally representative surveys of HIV drug resistance conducted between 2014 and 2018 in Cameroon, Guatemala, Honduras, Nicaragua, Senegal, Uganda, Vietnam and Zambia. METHODS: Prevalence of nucleoside reverse-transcriptase inhibitor resistance among participants with virological nonsuppression (viral load ≥1000 copies/ml) who had received TDF-based ART for 12-24 months (early ART group) and at least 40 months (long-term ART group) was assessed using Sanger sequencing and resistance was interpreted using the Stanford HIVdb algorithm. For each group, we estimated a pooled prevalence using random effect meta-analysis. RESULTS: Of 4677 participants enrolled in the surveys, 640 (13.7%) had virological nonsuppression, 431 (67.3%) were successfully genotyped and were included in the analysis; of those, 60.3% (260) were participants in the early ART group. Overall, 39.1, 57.9, 38.5 and 3.6% patients in the early ART group and 42.9, 69.3, 42.9 and 10.0% patients on long-term ART had resistance to TDF, XTC, TDF + XTC and TDF + XTC + zidovudine, respectively. Overall, tenofovir resistance was mainly due to K65R or K70E/G/N/A/S/T/Y115F mutations (79%) but also due to thymidine analogue mutations (21%) which arise from exposure to thymidine analogues but causing cross-resistance to TDF. CONCLUSION: Dual resistance to TDF + XTC occurred in more than 40% of the people with viral nonsuppression receiving tenofovir-based first-line ART, supporting WHO recommendation to optimize the nucleoside backbone in second-line treatment and cautioning against single drug substitutions in people with unsuppressed viral load.

Scale-up of national antiretroviral therapy programs: progress and challenges in the Asia Pacific region.

BACKGROUND: There has been tremendous scale-up of antiretroviral therapy (ART) services in the Asia Pacific region, which is home to an estimated 4.7 million persons living with HIV/AIDS. We examined treatment scale-up, ART program practices, and clinical outcome data in the nine low-and-middle-income countries that share over 95% of the HIV burden in the region. METHODS: Standardized indicators for ART scale-up and treatment outcomes were examined for Cambodia, China, India, Indonesia, Myanmar, Nepal, Papua New Guinea, Thailand, and Vietnam using data submitted by each country to the WHO/The Joint United Nations Programme on HIV/AIDS (UNAIDS)/UNICEF joint framework tool for monitoring the health sector response to HIV/AIDS. Data on ART program practices were abstracted from National HIV Treatment Guidelines for each country. RESULTS: At the end of 2009, over 700,000 HIV-infected persons were receiving ART in the nine focus countries. Treatment coverage varies widely in the region, ranging from 16 to 93%. All nine countries employ a public health approach to ART services and provide a standardized first-line nonnucleoside reverse transcriptase inhibitor-based regimen. Among patients initiated on first-line ART in these countries, 65-88% remain alive and on treatment 12 months later. Over 50% of mortality occurs in the first 6 months of therapy, and losses to follow-up range from 8 to 16% at 2 years. CONCLUSION: Impressive ART scale-up efforts in the region have resulted in significant improvements in survival among persons receiving therapy. Continued funding support and political commitment will be essential for further expansion of public sector ART services to those in need. To improve treatment outcomes, national programs should focus on earlier identification of persons requiring ART, decentralization of ART services, and the development of stronger healthcare systems to support the provision of a continuum of HIV care.