Strategies for the optimal sequencing of antiretroviral drugs toward overcoming and preventing drug resistance

Modeling Outcomes of First-Line Antiretroviral Therapy and Rate of CD4 Counts Change among a Cohort of HIV/AIDS Patients in Ethiopia: A Retrospective Cohort Study

Background

Antiretroviral therapy has shown to be effective in reducing morbidity and mortality in patients infected with HIV for the past couples of decades. However, there remains a need to better understand the characteristics of long-term treatment outcomes in resource poor settings. The main aim of this study was to determine and compare the long-term response of patients on nevirapine and efavirenz based first line antiretroviral therapy regimen in Ethiopia.

Methods

Hospital based retrospective cohort study was conducted from January 2009 to December 2013 at University hospital located in Northwest Ethiopia. Human subject research approval for this study was received from University of Gondar Research Ethics Committee and the medical director of the hospital. Cox-proportional hazards model was used to assess the effect of baseline covariates on composite outcome and a semi-parametric mixed effect model was used to investigate CD4 counts response to treatments.

Results

A total of 2386 HIV/AIDS naive patients were included in this study. Nearly one-in-four patients experienced the events, of which death, lost to follow up, treatment substitution and discontinuation of Non-Nucleoside Reverse Transcriptase Inhibitors(NNRTI) accounted: 99 (26.8%), 122 (33.0%), 137 (37.0%) and 12 (3.2%), respectively. The hazard of composite outcome on nevirapine compared with efavirenz was 1.02(95%CI: 0.52-1.99) with p-value = 0.96. Similarly, the hazard of composite outcome on tenofovir and stavudine compared with zidovudine were 1.87 (95%CI: 1.52-2.32), p-value < 0.0001 and 1.72(95% CI: 1.22-2.32), p-value = 0.002, respectively. The rate of CD4 increase in response to treatment was high during the first 10 months and stabilized later.

Conclusions

This study revealed that treatment responses were comparable whether nevirapine or efavirenz was chosen to initiate antiretroviral therapy for HIV/AIDS patients in Ethiopia. There was significant difference on risk of composite outcome between patients who were initiated with Tenofovir containing ART regimen compared with zidovudine after controlling for NNRTI drug combinations.

The effectiveness of social resource intervention to promote adherence to HIV medication in a multidisciplinary care setting in Kenya

Adherence to HIV medication has a dramatic impact on morbidity, mortality and health in people living with HIV. Recent studies have demonstrated good adherence to HIV medication among people in sub-Saharan Africa, but few have investigated factors influencing adherence. The goal of this study was to evaluate the effectiveness of social intervention strategies to enhance adherence to HIV medication. A cross-sectional design study was used to obtain data through self-administered questionnaires from 354 individuals who were prescribed HIV medication at nine satellite centres under the auspice of the Nazareth Hospital in Kenya. Binomial logistics were used to test the relationships between social support and its dimensions with adherence to HIV medication. Composite social support was predictive of adherence to HIV medication (P < 0.05). Among the four dimensions of support, material and emotional support were the strongest predictors.

Structural and thermodynamic basis of amprenavir/darunavir and atazanavir resistance in HIV-1 protease with mutations at residue 50

Drug resistance occurs through a series of subtle changes that maintain substrate recognition but no longer permit inhibitor binding. In HIV-1 protease, mutations at I50 are associated with such subtle changes that confer differential resistance to specific inhibitors. Residue I50 is located at the protease flap tips, closing the active site upon ligand binding. Under selective drug pressure, I50V/L substitutions emerge in patients, compromising drug susceptibility and leading to treatment failure. The I50V substitution is often associated with amprenavir (APV) and darunavir (DRV) resistance, while the I50L substitution is observed in patients failing atazanavir (ATV) therapy. To explain how APV, DRV, and ATV susceptibility are influenced by mutations at residue 50 in HIV-1 protease, structural and binding thermodynamics studies were carried out on I50V/L-substituted protease variants in the compensatory mutation A71V background. Reduced affinity to both I50V/A71V and I50L/A71V double mutants is largely due to decreased binding entropy, which is compensated for by enhanced enthalpy for ATV binding to I50V variants and APV binding to I50L variants, leading to hypersusceptibility in these two cases. Analysis of the crystal structures showed that the substitutions at residue 50 affect how APV, DRV, and ATV bind the protease with altered van der Waals interactions and that the selection of I50V versus I50L is greatly influenced by the chemical moieties at the P1 position for APV/DRV and the P2 position for ATV. Thus, the varied inhibitor susceptibilities of I50V/L protease variants are largely a direct consequence of the interdependent changes in protease inhibitor interactions.

Coping self-efficacy as a predictor of adherence to antiretroviral therapy in men and women living with HIV in Kenya

The purpose of this study was to evaluate the relationship between the coping self-efficacy (CSE) scale and adherence to HIV medication in men and women enrolled in a large HIV treatment program in Kenya. Data were collected from a sample of 354 volunteers attending Nazareth Hospital's nine satellite clinics located in parts of Nairobi, and the central province of Kenya. A social demographic survey, Adult Clinical Trials Group adherence questionnaire, and CSE scale were used to obtain information. Descriptive statistics and logistic regressions were performed to analyze data and to test study hypotheses. Females were less likely to be nonadherent than males: the odds of adherence for females were 3.7 of the odds of adherence for males. Controlling for gender, CSE was significant. Adherence to antiretroviral therapy can be partially explained by CSE. Efforts aimed at building self-efficacy are likely to improve and maintain adherence to HIV and other medication. Implications, limitations, and future directions are discussed.

Psychosocial issues influencing treatment adherence in patients on multidrug rescue therapy: perspectives from patients and their health care providers

Multi-drug rescue therapy (MDRT) is often used for the treatment of highly experienced patients who harbor HIV variants with decreased susceptibility to multiple antiretrovirals. Patients on MDRT typically have limited treatment options, and without treatment, their prognosis can be poor. Yet the decision to go on MDRT is not always straightforward as MDRT can be associated with significant challenges including multiple daily doses, higher pill burden, emerging toxicities, and drug interactions. All of these may compromise adherence, which is often a major reason why patients may need MDRT in the first place. Little is known about how patients and health care providers (HCPs) experience MDRT. This study sought to explore areas of convergence and divergence between patients and HCPs in order to identify gaps in treatment and factors that may impact adherence to MDRT. A qualitative interview method based on grounded theory was used. Twelve patients and seven HCPs completed a 60-minute semistructured interview. Patients were asked about challenges, facilitative aspects of staying on MDRT, the decision to initiate treatment, their role, and the role of HCPs in their health care. HCPs were asked about their experience working with MDRT patients, their role, and the role of the patient. Congruent themes emerged from the two groups: developing a working relationship, treatment factors, information requirements, and readiness for treatment. There were no discrepancies in role perspectives. Patients and HCPs agreed on the need to optimize patients' readiness, willingness, and ability to embark on MDRT to maximize adherence. HCPs assumptions about beginning MDRT based solely on medical indications must be checked and discussed to ensure patients' motivation. In conclusion, adherence to MDRT demands a substantial behavior change, recognized as a major challenge by patients. Allocating the time to make a commitment to treatment can optimize adherence. It is therefore crucial that patients be provided with time to make informed decisions, explore and resolve their willingness and readiness to commit to treatment, and maintain supportive relationships with their HCPs, all of which can optimize adherence to MDRT.