Basis of selection of first and second line highly active antiretroviral therapy for HIV/AIDS on genetic barrier to resistance: a literature review

Broadening access to tenofovir alafenamide for the treatment and prevention of HIV-1 infection

INTRODUCTION

Tenofovir alafenamide (TAF), a prodrug of tenofovir, achieves higher intracellular concentrations of tenofovir-diphosphate and 90% lower plasma concentrations of tenofovir compared to tenofovir disoproxil fumarate (TDF). TAF is associated with improved renal and bone safety outcomes.

AREAS COVERED

We review the efficacy and safety of TAF-containing regimens in adults and pediatrics. We highlight safety data during pregnancy, drug interactions during co-administration with tuberculosis treatment, and critical knowledge gaps to be addressed for the successful implementation of TAF in low- and middle-income countries. We performed a search on MEDLINE PubMed and conference websites for relevant articles published from January 2010 to March 2023.

EXPERT OPINION

Current evidence demonstrates that TAF has similar efficacy and tolerability, superior bone and renal safety, and higher rates of dyslipidemia and weight gain, compared with TDF. However, there are several knowledge gaps, in specific sub-populations, that require action. Emerging data suggests that TAF is safe during pregnancy, although fuller safety data to support TAF use in pregnancy is needed. Similarly, there is a lack of evidence that TAF can be used in combination with rifamycin-based tuberculosis treatment in PWH and TB. Further studies are needed to fill knowledge gaps and support the wider rollout of TAF.

Utilization Trends of Antiviral and Antifungal Agents for Human Systemic Use in Tanzania From 2010 to 2017 Using the World Health Organization Collaborating Centre for Drug Statistics Methodology

Introduction

The increase in antimicrobial consumption contributes to the emergence of antimicrobial resistance (AMR). Many studies have investigated the patterns of antibacterial consumption and antibacterial resistance. However, there is a paucity of data on the utilization of antivirals and antifungals in low and middle-income countries to serve as a baseline for monitoring and surveillance of AMR. Therefore, this study determined Tanzania’s systemic antifungal and antiviral utilization trends from 2010 to 2017, based on the Tanzania Medicines and Medical Devices Authority (TMDA) medicine importation archives.

Methodology

An analytical, longitudinal retrospective survey covering 2010 to 2017 was conducted. The study utilized the Anatomical Therapeutic and Chemical (ATC) classification and Defined Daily Dose (DDD) developed by the World Health Organization (WHO) Collaborating Centre for Drug Statistics and the WHO Collaboration Centre for International Drug Consumption Monitoring. Human medicine importation data were collected from TMDA headquarters and used to assess the systemic antiviral and antifungal consumption trends. The importation data included the date, generic name, strength, brand name, currency, quantity, ATC classification, supplier country, port of entry and product supplier. The data were cleaned, reorganized and analyzed. Reference was made to the latest revised DDD list to assign antifungals and antivirals to their respective ATC/DDDs and then adjusted to the population estimates from the National Bureau of Statistics of Tanzania.

Results

There was a high proportion of systemic antivirals and antifungals utilization with 367.1 and 10.8 DDD per 1000 inhabitants per day (DID) respectively over eight years. In regression model, there was a significant increase in both antiviral (p-value = 0.043) and antifungal (p-value = 0.015) agents’ utilization trends in Tanzania in the study period. Fluconazole had the highest proportion of utilization for antifungals, followed by ketoconazole, itraconazole, miconazole and amphotericin B. For systemic antivirals, a high proportion was attributed to antiretrovirals used for HIV infections.

Conclusion

Findings from this study suggest an increase in the utilization of systemic antiviral and antifungal agents. These findings may be used to further benchmark utilization and AMR studies in Tanzania.

High Detection Rate of HIV Drug Resistance Mutations among Patients Who Fail Combined Antiretroviral Therapy in Manaus, Brazil

Virologic failure may occur because of poor treatment adherence and/or viral drug resistance mutations (DRM). In Brazil, the northern region exhibits the worst epidemiological scenarios for the human immunodeficiency virus (HIV). Thus, this study is aimed at investigating the genetic diversity of HIV-1 and DRM in Manaus. The cross-sectional study included people living with HIV on combined antiretroviral therapy and who had experienced virological failure during 2018-2019. Sequencing of the protease/reverse transcriptase (PR/RT) and C2V3 of the viral envelope gp120 (Env) regions was analyzed to determine subtypes/variants of HIV-1, DRMs, and tropism. Ninety-two individuals were analyzed in the study. Approximately 72% of them were male and 74% self-declared as heterosexual. Phylogenetic inference (PR/RT-Env) showed that most sequences were B subtype, followed by BF1 or BC mosaic genomes and few F1 and C sequences. Among the variants of subtype B at PR/RT, 84.3% were pandemic (B_PAN), and 15.7% were Caribbean (B_CAR). The DRMs most frequent were M184I/V (82.9%) for nucleoside reverse transcriptase inhibitors (NRTI), K103N/S (63.4%) for nonnucleoside reverse transcriptase inhibitor (NNRTI), and V82A/L/M (7.3%) for protease inhibitors (PI). DRM analysis depicted high levels of resistance for lamivudine and efavirenz in over 82.9% of individuals; although, low (7.7%) cross-resistance to etravirine was observed. A low level of resistance to protease inhibitors was found and included patients that take atazanavir/ritonavir (16.6%) and lopinavir (11.1%), which confirms that these antiretrovirals can be used—for most individuals. The thymidine analog mutations-2 (TAM-2) resistance pathway was higher in B_CAR than in B_PAN. Similar results from other Brazilian studies regarding HIV drug resistance were observed; however, we underscore a need for additional studies regarding subtype B_CAR variants. Molecular epidemiology studies are an important tool for monitoring the prevalence of HIV drug resistance and can influence the public health policies.

Antiretroviral drug-S for a possible HIV elimination

Although the combination of highly active antiretroviral therapy (cART) can remarkably control human immunodeficiency virus type-1 (HIV-1) replication, it fails to cure HIV/AIDS disease. It is attributed to the incapability of cART to eliminate persistent HIV-1 contained in latent reservoirs in the central nervous system (CNS) and other tissue organs. Thus, withdrawal of cART causes rebound viral replication and resurgent of HIV/AIDS. The lack of success on non-ART approaches for elimination of HIV-1 include the targeted molecules not reaching the CNS, not adjusting well with drug-resistant mutants, or unable to eliminate all components of viral life cycle. Here, we show that our newly discovered Drug-S can effectively inhibit HIV-1 infection and persistence at the low concentration without causing any toxicity to neuroimmune cells. Our results suggest that Drug-S may have a direct effect on viral structure, prevent rebounding of HIV-1 infection, and arrest progression into acquired immunodeficiency syndrome. We also observed that Drug-S is capable of crossing the blood-brain barrier, suggesting a potential antiretroviral drug for elimination of CNS viral reservoirs and self-renewal of residual HIV-1. These results outlined the possible mechanism(s) of action of Drug-S as a novel antiretroviral drug for elimination of HIV-1 replication by interfering the virion structure.