In this 13-week, open-label, randomized study of the anti-inflammatory salsalate versus usual care, there were no significant improvements in flow-mediated dilation of the brachial artery, endothelial activation, inflammation or coagulation markers, homeostasis model assessment of insulin resistance or lipoproteins with salsalate or between groups in virologically suppressed, HIV-infected adults on antiretrovirals. Tinnitus and transaminitis occurred frequently in the salsalate group. Dose reduction due to toxicities encountered and low level of inflammation may explain these results.
University Hospitals Case Medical Center and Case Western Reserve University, Cleveland, Ohio, USA.
Received 8 January, 2010
Revised 5 May, 2010
Accepted 14 May, 2010
Correspondence to Grace A. McComsey, MD, Professor of Pediatrics and Medicine, Case Western Reserve University, 11100 Euclid Avenue, Cleveland, OH 44106, USA. Tel: +1 216 844 3645; fax: +1 216 844 3926; e-mail: firstname.lastname@example.org
In HIV, inflammation is an important target to study to decrease cardiovascular disease (CVD) risk. Inflammatory markers correlate with flow-mediated dilation (FMD) of the brachial artery , endothelial markers  and carotid intima–media thickness , as well as predict incident diabetes .
Salsalate inhibits the IkappaB kinase beta/nuclear factor kappaB (NF-κB) pathway , a central integrator of proinflammatory signals and mediator of vascular inflammation [6,7]. The role of this pathway in CVD is being defined, although activated NF-κB has been found in atherosclerotic lesions . Further, HIV-1 utilizes NF-κB for replication  and viral proteins activate this pathway leading to chemokine upregulation .
Salsalate is well tolerated and improves inflammation, endothelial activation and glycemia in other populations [10–12]. Within HIV, an uncontrolled study in adults not on antiretroviral therapy (ART) showed that salsalate increased FMD by 4.2% after 8 weeks . Hence, the goal of our study was to evaluate for the first-time safety and efficacy of salsalate on inflammation, FMD and insulin resistance in virologically suppressed adults on ART.
We conducted a 13-week, open-label, randomized trial. Participants were randomized 1: 1 to salsalate 4 g/day or no intervention. HIV-1-infected adults on stable ART with HIV-1 RNA 400 copies/ml or less for 12 weeks were considered. Major exclusions included pregnancy, diabetes mellitus, creatinine clearance of less than 50 ml/min, history of bleeding peptic ulcer, aspartate aminotransferase/alanine aminotransferase more than two times normal, hepatitis B or C, active infectious/inflammatory condition, regular use of anti-inflammatory medication, anticoagulation or medications that interact with salsalate and daily alcohol use. Participants signed an informed consent approved by the local institutional review board.
Dose escalation instructions for salsalate were given to minimize gastrointestinal upset. Participants started 1 g twice daily and increased 500 mg every 2 days until 2 g twice daily or toxicity developed. Participants returned twice monthly for safety and adherence monitoring. Endpoints were measured at entry and week 13. Our primary endpoint was endothelial function determined by FMD . Ultrasound measurement of FMD is noninvasive, reproducible  and strongly correlated with coronary artery FMD (r = 0.78, P < 0.001) . Endothelial dysfunction predicts future atherosclerosis and is present before appearance of arterial wall thickening . As a functional marker of CVD responding rapidly to interventions, FMD is well suited to study the effect of salsalate on CVD risk. The technician (C.A.W.) and reader (T.L.C.) were blinded. FMD was performed as previously described  using an L10–7 MHz linear array transducer and 5-min occlusion time. FMD is expressed as percentage change from baseline arterial diameter-to-diameter after reactive hyperemia. For secondary endpoints, real-time fasting glucose, insulin and lipoproteins were performed and plasma was stored for measurement of biomarkers (see Table 1). Insulin resistance was estimated using homeostasis model assessment of insulin resistance (HOMA-IR) .
Results are reported as absolute change from baseline. Wilcoxon rank sum and signed rank tests were used for between-group and within-group comparisons, respectively. Spearman correlations were used to evaluate relationships between continuous variables. Percentage adherence = [(pills dispensed − pills returned)/expected number taken] × 100. Analyses were performed using SAS, version 9.2 (SAS Institute, Carey, North Carolina, USA).
From 20 January to 29 April 2009, 40 individuals were enrolled. Participants did not differ at baseline. Overall, the median [interquartile range (IQR)] age (years) was 46 (43.5–50); 95% were men and 57.5% whites. All participants were on ART [55% on protease inhibitor, 47.5% on nonnucleoside reverse transcriptase inhibitor (NNRTI)] with HIV-1 RNA 400 copies/ml or less (84% had HIV-1 RNA less than or equal to 50 copies/ml). The median (IQR) years on ART was 8.75 (6–12). The median (IQR) nadir and entry CD4+ cell counts (cells/μl) were 141 (90–294) and 680 (515–996), respectively. Overall, 40% smoked, 27.5% had hypertension and 20% had hypercholesterolemia. The median (IQR) Framingham risk was 3.5% (2–6%).
Table 1 shows entry and change in outcomes. The median (IQR) FMD change from baseline was 0.99 (−2.56 to 1.91; P = 0.93) for those on salsalate and −0.07 (−3.53 to 1.95; P = 0.65) for controls (P = 0.61 between groups). Limiting to those taking at least 3 g/day (11/20) and with salsalate levels (mg/dl) of at least 10 (7/20) and at least 5 (10/20) at week 13 did not change the results. FMD change was not correlated with baseline or changes in CD4+ cell count, low-density lipoprotein, high-density lipoprotein HOMA-IR, inflammation or coagulation markers.
Baseline biomarkers were not statistically different between groups nor were biomarker changes, except IL-6 and fibrinogen-favoring controls. Within-group changes are noted in Table 1. Fasting HOMA-IR, lipoproteins, blood pressure and BMI were not different between groups at baseline and there were no significant within-group or between-group changes. The median (IQR) percentage adherence to salsalate was 96% (88–100%).
Salsalate was not well tolerated. The median (IQR) ending dose (g/day) was 3 (1–4). Only 55% (11/20) finished taking at least 3 g salsalate/day. Toxicities included tinnitus (9/20), transaminitis (6/20; grade 1 in 4/20 and grade 2 in 2/20), headache (2/20), abdominal pain (1/20), nausea (2/20), neutropenia (2/20), thrombocytopenia (2/20) and rash (1/20). Three participants withdrew: one due to symptomatic, prolonged, grade 2 transaminitis, one due to tinnitus and grade 2 transaminitis, and one due to rash.
In ART-naive patients, the best strategy to decrease inflammation is likely ART . Thus, the need for non-ART anti-inflammatory agents is more urgent in patients on ART. Our data show that salsalate did not reduce inflammation in this group over 13 weeks, a duration chosen to avoid missing an effect while still assessing tolerance [13,20,21]. We speculate that is why no effect was seen in endothelial dysfunction or insulin resistance.
We considered two explanations for the lack of effect. Perhaps doses tolerated were too low. A recent study showed that the dose needed to decrease C-reactive protein was 4.5 g/day, which is higher than the median dose in our study of 3 g/day . Further, the median week-13-salicylate level was 5 mg/dl, which is below the usual therapeutic range. Alternatively, perhaps inflammation in this virologically suppressed group was not substantial enough for NF-κB pathway inhibition to have a meaningful effect on the outcomes.
Limitations of this study are lack of placebo precluding effective blinding, known limitations of pill counts as an adherence measure and small sample size. Although detecting a small effect may have been meaningful with regard to the pathogenesis of endothelial dysfunction and insulin resistance in this population, clinical use of salsalate for this indication would have been questionable, especially in light of the toxicities encountered.
In conclusion, virologically suppressed, HIV-infected adults on ART did not show improvement in endothelial function or insulin resistance after 13 weeks of salsalate.
The authors would like to thank the patients who participated in this research, Bristol-Myers Squibb for grant support through the Virology Fellows Research Program for Dr Hileman and the Case Center for AIDS Research (NIH grant number AI36219).
G.A.M. has received research grant support and serves as a consultant for GlaxoSmithKline, Bristol-Myers Squibb, Gilead Sciences and Abbott and currently serves as the DMC Chair for a Pfizer-sponsored clinical trial.
C.O.H., B.M.G. and G.A.M. conceived the study concept. C.O.H., B.M.G., N.J.S., D.E.H. and G.A.M. organized the study. C.A.W. performed the FMD studies. T.L.C. read the FMD studies. C.O.H. did the statistical analysis. M.O. provided support in the statistical analysis. All authors contributed to the development of the manuscript.
Data presented previously at the 11th International Workshop on Adverse Drug Reactions and Co-morbidities in HIV from 26 to 28 October 2009 in Philadelphia, Pennsylvania, USA.
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