Comparison of Single and Boosted Protease Inhibitor Versus Nonnucleoside Reverse Transcriptase Inhibitor–Containing cART Regimens in Antiretroviral-Naïve Patients Starting cART After January 1, 2000

Novel Approaches for Visualizing and Analyzing Dose-Timing Data from Electronic Drug Monitors, or "How the 'Broken Window' Theory Pertains to ART Adherence"

Adherence to antiretroviral medications is usually expressed in terms of the proportion of doses taken. However, the timing of doses taken may also be an important dimension to overall adherence. Little is known about whether patients who mistime doses are also more likely to skip doses. Using data from the completed Adherence for Life randomized controlled trial, we created visual and statistical models to capture and analyze dose timing data collected longitudinally with electronic drug monitors (EDM). From scatter plots depicting dose time versus calendar date, we identified dominant patterns of dose taking and calculated key features [slope of line over calendar date; residual mean standard error (RMSE)]. Each was assessed for its ability to categorize subjects with 'sub-optimal' (<95 % of doses taken) using area under the receiver operating characteristic (AROC) curve analysis. Sixty eight subjects contributed EDM data, with ~300 to 400 observations/subject. While regression line slopes did not predict 'sub-optimal' adherence (AROC 0.51, 95 % CI 0.26-0.75), the variability in dose timing (RMSE) was strongly predictive (AROC 0.79, 95 % CI 0.62-0.97). Compared with the lowest quartile of RMSE (minimal dose time variability), each successive quartile roughly doubled the odds of 'sub-optimal' adherence (OR 2.1, 95 % CI 1.3-3.4). Patterns of dose timing and mistiming are strongly related to overall adherence behavior. Notably, individuals who skip doses are more likely to mistime doses, with the degree of risk positively correlated with the extent of dose timing variability.

[Enhancing immune restoration in human immunodeficiency virus infection]

The primary objective of antiretroviral therapy has recently evolved from a virologic endpoint towards the achievement of normal CD4T cell count (greater than 500/mm(3)) to avoid progression to AIDS. This shift in the primary objective is supported by many clinical and epidemiological studies. Recent data have shown that HIV-infected adults with a CD4T cell count greater than 500cells/mm(3) on long-term combination antiretroviral therapy reach same mortality rates as the general population. However, less than 50% of patients receiving long-term suppressive antiretroviral combination reach such a CD4T cell level. New antiretroviral strategies to improve immune reconstitution, such as specific or non-specific immune-based therapy on one hand and the use of novel antiretroviral drugs from new classes on the other hand are currently under investigation. Here we review several current strategies that may improve immune reconstitution, keeping in mind that the best way to reach normal CD4T cell count is an early treatment initiation.

A comparison of the long-term durability of nevirapine, efavirenz and lopinavir in routine clinical practice in Europe: a EuroSIDA study

OBJECTIVES

The durability of combination antiretroviral therapy (cART) regimens can be measured as time to discontinuation because of toxicity or treatment failure, development of clinical disease or serious long-term adverse events. The aim of this analysis was to compare the durability of nevirapine, efavirenz and lopinavir regimens based on these measures.

METHODS

Patients starting a nevirapine, efavirenz or lopinavir-based cART regimen for the first time after 1 January 2000 were included in the analysis. Follow-up started ≥ 3 months after initiation of treatment if viral load was <500 HIV-1 RNA copies/mL. Durability was measured as discontinuation rate or development/worsening of clinical markers.

RESULTS

A total of 603 patients (21%) started nevirapine-based cART, 1465 (51%) efavirenz, and 818 (28%) lopinavir. After adjustment there was no significant difference in the risk of discontinuation for any reason between the groups on nevirapine and efavirenz (P=0.43) or lopinavir (P=0.13). Compared with the nevirapine group, those on efavirenz had a 48% (P=0.0002) and those on lopinavir a 63% (P<0.0001) lower risk of discontinuation because of treatment failure and a 31% (P=0.01) and 66% (P<.0001) higher risk, respectively, of discontinuation because of toxicities or patient/physician choice. There were no significant differences in the incidence of non-AIDS-related events, worsening anaemia, severe weight loss, increased aspartate aminotransferase (AST)/alanine aminotransferase (ALT) levels or increased total cholesterol. Compared with patients on nevirapine, those on lopinavir had an 80% higher incidence of high-density lipoprotein (HDL) cholesterol decreasing below 0.9 mmol/L (P=0.003), but there was no significant difference in this variable between those on nevirapine and those on efavirenz (P=0.39).

CONCLUSIONS

The long-term durability of nevirapine-based cART, based on risk of all-cause discontinuation and development of long-term adverse events, was comparable to that of efavirenz or lopinavir, in patients in routine clinical practice across Europe who initially tolerated and virologically responded to their regimen.

HIV dynamics and integrase inhibitors

The integrase inhibitor (INI) raltegravir has shown promising results in clinical trials to date, reducing second phase HIV RNA levels by 70% in comparison with standard regimens. These trial results have been limited by the 50 copies/ml detection limit of the HIV RNA assay and have not investigated the effect of an INI regimen on levels of latently infected cells. Mathematical models that duplicated previous raltegravir results were extended to estimate effects of an INI regimen on HIV RNA beyond second phase and on HIV DNA levels. Depending on assumptions underlying later phase HIV RNA generation and its interaction with latently infected cells, HIV RNA in later phases can be lower or show no difference with an INI, and similarly for HIV DNA. If latent infection is maintained by differentiation of stem cells with integrated HIV DNA, then an INI regimen will eventually have no added benefit. Other hypotheses that allow ongoing replication predict continually lower HIV RNA levels with an INI regimen, but this differential effect need not translate to a reduction in latent infection. Investigation of HIV RNA and HIV DNA levels with an INI will provide better understanding of how these components are generated and maintained under antiretroviral therapy.

Patterns, predictors, and consequences of initial regimen type among HIV-infected women receiving highly active antiretroviral therapy

BACKGROUND

It is important to elucidate differences among initial highly active antiretroviral therapy (HAART) regimen types in comparative studies of therapy effectiveness. We aimed to identify predictors of initiation with different HAART regimen types and the effect of initial regimen type on switching and immunologic response to therapy--controlling for those predictors--among human immunodeficiency virus (HIV)-infected women in the United States.

METHODS

Participants in the Women's Interagency HIV Study underwent semiannual interview, venipuncture, and clinical examination. Those beginning with protease inhibitor-based, nonnucleoside reverse-transcriptase inhibitor (NNRTI)-based, or triple-nucleoside reverse-transcriptase inhibitor (NRTI)-based HAART during April 1996-March 2005 were eligible for analysis. Predictors of initial regimen type were assessed with polytomous logistic regression. Correlates of switching were assessed with discrete-time proportional hazards models, and immunologic response to therapy was assessed with linear regression.

RESULTS

Among 1555 HAART initiators, CD4(+) lymphocyte count and HIV load were significant predictors of initial regimen type during 1996-2002; only sociodemographic predictors were significant during 2002-2005. Initial regimen type was not a significant predictor of subsequent regimen switching. Compared with those whose initial treatment was protease inhibitor-based HAART, those who began with triple-NRTI-based regimens had significantly lower CD4(+) cell counts at 1 year (P=.006) and 2 years (P=.004) after initiation; NNRTI initiators had lower CD4(+) cell counts after 2 years (P=.05).

CONCLUSIONS

We demonstrate that predictors of initial regimen type among women in the United States have been changing over time. Protease inhibitor initiators had significantly higher CD4(+) cell counts than did NNRTI or triple-NRTI initiators up to 2 years after HAART initiation. Adjustment for biological predictors of initial regimen is important to avoid confounding in the study of treatment effectiveness.