The future of HIV treatment

A systematic review and meta-analysis assessing antiretroviral therapy for treatment-experienced HIV adult patients using an optimized background therapy approach: is there evidence enough for a standardized third-line strategy?

BACKGROUND

The World Health Organization (WHO) has identified the need for evidence on third-line antiretroviral therapy (ART) for adults living with HIV/AIDS, given that some controversy remains as to the best combinations of ART for experienced HIV-1-infected patients. Therefore, we conducted a systematic review and meta-analysis to (i) assess the efficacy of third-line therapy for adults with HIV/AIDS based on randomized controlled trials (RCT) that adopted the "new antiretroviral (ARV) + optimized background therapy (OBT)" approach and (ii) address the key issues identified in WHO's guidelines on the use of third-line therapy.

METHODS

MEDLINE, EMBASE, LILACS, ISI Web of Science, SCOPUS, and Cochrane Central Register of Controlled Trials were searched for RCTs assessing third-line ARV therapy that used an OBT approach between 1966 and 2015. Data was extracted using an Excel-structured datasheet based on the Consolidated Standards of Reporting Trials (CONSORT) recommendations. The primary outcome of this meta-analysis was the proportion of patients reaching undetectable HIV RNA levels (< 50 copies/mL) at 48 weeks of follow-up. Included studies were evaluated using the Cochrane's Risk of Bias assessment tool. Summarized evidence was rated according to the GRADE approach.

RESULTS

Eighteen trials assessing 9 new ARV + OBT combinations defined as third-line HIV therapy provided the efficacy data: 7 phase IIb trials and 11 phase III trials. Four of the 18 trials provided extension data, thus resulting in 14 trials providing 48-week efficacy data. In the meta-analysis, considering the outcome regarding the proportion of patients with a viral load below 50 copies/ml at 48 weeks, 9 out of 14 trials demonstrated the superiority of the new combination being studied (risk difference = 0.18, 95% CI 0.13-0.23). The same analysis stratified by the number of fully active ARVs demonstrated a risk difference of 0.29 (95% CI 0.12-0.46), 0.28 (95% CI 0.17-0.38) and 0.17 (95% CI 0.10-0.24) respectively from zero, one, and two or more active drugs strata. Nine of the 18 trials were considered to have a high risk of bias.

CONCLUSIONS

Efficacy results demonstrated that the groups of HIV-experienced patients receiving the new ARV + OBT were more likely to achieve viral suppression when compared to the control groups. However, most of these trials may be at a high risk of bias. Thus, there is still not enough evidence to stipulate which combinations are the most effective for therapeutic regimens that are to be used sequentially due to documented multi-resistance.

Rationale and clinical utility of the darunavir-cobicistat combination in the treatment of HIV/AIDS

This article is to provide an update overview of cobicistat (COBI)-boosted darunavir in response to its recent approval by the US Food and Drug Administration, and inclusion as an alternative first-line regime in the 2015 treatment guidelines in the US. COBI is a relatively new non-antiretroviral cytochrome P450 3A inhibitor or pharmacoenhancer. The rationale behind COBI development was to provide an alternative to ritonavir (RTV) as a protease inhibitor pharmacoenhancer, due to associated adverse events with short- and long-term RTV use, such as gastrointestinal intolerability, drug–drug interactions, insulin resistance, lipodystrophy, and hyperlipidemia. Although in vitro studies suggest that COBI may result in a lower incidence of undesired drug–drug interactions and lipid-associated disorders than RTV, not all Phase III studies have well addressed these issues, and the data are limited. However, Phase III studies have demonstrated tolerability, noninferiority, and bioequivalence of COBI compared to RTV. Two main advantages of COBI over RTV-containing regimes have been noted as follows: 1) COBI has no anti-HIV activity; therefore, resistance to COBI as a booster in addition to protease inhibitor resistance is of little concern, allowing for COBI-containing regimes in future. 2) COBI’s solubility and dissolution rate allow for co-formulated/fixed-dose combination products. Nonetheless, prior to initiating COBI-containing treatment regimens, the following should be considered: 1) COBI may increase serum creatinine levels and reduce estimated glomerular filtration rate (GFR) without affecting actual GFR; 2) potential drug–drug interaction data are insufficient, warranting caution when initiating COBI in conjunction with concomitant medication or in individuals with multiple comorbidities; 3) food plays a pivotal role in boosting darunavir exposure, warranting caution and patient education on the importance of taking COBI-containing regimens with appropriate amounts of food; and 4) data on the success of COBI-containing regimens in treatment-experienced patients are limited.