Simplification to Stribild vs continuation of RTV-boosted DRV with FTC and TDF in virologically suppressed HIV adults: a STRATEGY-PI subgroup analysis.

INTRODUCTION: Simplification to Stribild (STB) was statistically superior to continuation of a ritonavir-boosted protease inhibitor (PI+RTV) with emtricitabine and tenofovir DF (FTC/TDF) at week (W) 48 in virologically suppressed HIV adults (1). We report the W48 efficacy and safety of STB versus RTV-boosted darunavir (DRV) with FTC/TDF in suppressed subjects. MATERIAL AND METHODS: Virologically suppressed subjects on PI+RTV with FTC/TDF regimens for ≥6 months were randomized (2:1) to switch to STB vs continue their PI regimen. Eligibility criteria included no documented resistance to FTC and TDF, no history of virologic failure and eGFR ≥70 mL/min. The primary endpoint was the proportion of subjects in the modified ITT population who maintained HIV-1 RNA <50 copies(c)/mL at W48 by FDA snapshot algorithm (12% non-inferiority margin). Subgroup analysis by PI use (DRV [173], atazanavir [174], lopinavir [72], Other PI [13]) at screening was pre-specified. RESULTS: Four hundred twenty-nine subjects were randomized and treated (mITT set). In the DRV subgroup, 113 switched to STB; 60 continued a RTV-boosted DRV with FTC/TDF. At W48, 95% STB versus 92% DRV maintained HIV-1 RNA <50 c/mL. No emergent resistance was detected in either group. Median increases from baseline in CD4 count at week 48 (cells/µL): 28 STB versus 29 DRV (p=0.81). Discontinuations due to adverse events were 3% STB versus 2% DRV; one case of isolated decrease in eGFR in the DRV group and no cases of proximal renal tubulopathy in either group. There were statistically significant decreases in the frequency of diarrhoea reported on the HIV Symptom Index at week 4 to week 48 compared to baseline after switching to STB. There was a greater but non-progressive decrease from baseline in eGFR in the STB vs DRV group; median changes (mL/min) at week 48: -8.5 vs -0.6, consistent with the known cobicistat inhibition of renal creatinine secretion. Switch to STB was associated with a higher treatment ease (convenience, flexibility, demand, lifestyle, understanding) score (range: -15 to 15) at week 4 (median: 12 vs 9; p=0.006) and week 24 (median: 13 vs 8; p=0.001). CONCLUSIONS: In this small group of virologically suppressed subjects, simplification to STB versus continuation of a RTV-boosted DRV with FTC/TDF was safe, well-tolerated, and associated with a high rate of virologic suppression at week 48. There was more treatment ease with STB use.

Efficacy and safety of maraviroc versus efavirenz, both with zidovudine/lamivudine: 96-week results from the MERIT study.

BACKGROUND: The MERIT study evaluated maraviroc versus efavirenz, both with zidovudine/lamivudine, in treatment-naïve patients with CCR5-tropic (R5) HIV-1. Post hoc analyses previously assessed week 48 outcomes in patients rescreened with R5 virus by a more sensitive tropism assay. METHODS: Week 96 efficacy (post hoc, n = 614) and safety (n = 721) were assessed. RESULTS: Proportions of subjects <50 copies/mL (58.8% maraviroc, 62.7% efavirenz) and time to loss of virologic response (TLOVR) responders (<50 copies/mL: 60.5% vs 60.7%) were similar. Maraviroc recipients had greater CD4 increases (+ 212 vs + 171 cells/mm(3)) and fewer adverse event discontinuations (6.1% vs 15.5%), malignancies, and category C events. CONCLUSION: Week 96 data confirm week 48 observations in MERIT.

The safety of azithromycin in the treatment of adults with community-acquired respiratory tract infections.

The comparative safety of azithromycin was assessed in adult patients (> or =12 years) with community-acquired respiratory tract infections. Of 3229 patients evaluated, 1616 received azithromycin 500 mg once daily for 3 days and 1613 received standard regimens of amoxycillin, amoxycillin/clavulanic acid, cefaclor, clarithromycin, or roxithromycin. A similar incidence of treatment-related adverse events occurred with azithromycin (10.3%) and comparators (11.5%). Significantly fewer patients were withdrawn from azithromycin than comparator treatment (0.4 versus 2.1%; P=0.0001). Most adverse events were mild/moderate in intensity and affected the gastrointestinal system. Azithromycin was as well tolerated as other antibiotics commonly used for bacterial infections in adults.

The effect of carbon dioxide on susceptibility testing of azithromycin, clarithromycin and roxithromycin against clinical isolates of Streptococcus pneumoniae and Streptococcus pyogenes by broth microdilution and the Etest: Artemis Project-first-phase study.

OBJECTIVE: To evaluate the effect of carbon dioxide on the susceptibility testing, using broth microdilution and the Etest (AB Biodisk, Solna, Sweden), of azithromycin, clarithromycin and roxithromycin against Streptococcus pneumoniae and Streptococcus pyogenes. METHODS: Fresh clinical isolates collected from 36 hospital laboratories in 12 countries were evaluated using the Etest in the presence of carbon dioxide. The isolates were retested under ambient conditions (absence of carbon dioxide) using broth microdilution and/or the Etest. RESULTS: Carbon dioxide falsely elevated azithromycin, clarithromycin and roxithromycin MIC90S for S. pneumoniae, determined by the Etest, approximately 12-fold. Also, the azithromycin MIC90 for S. pyogenes was increased fourfold; the effect was less marked for clarithromycin and roxithromycin. When isolates were retested in the absence of carbon dioxide, using the Etest or microdilution, susceptibilities to azithromycin were comparable to those to clarithromycin (S. pneumoniae, 93.4% versus 91.3%; S. pyogenes, 96.4% versus 95.8%). Both organisms were less susceptible to roxithromycin (S. pneumoniae, 71.3%; S. pyogenes, 85.7%). An internal standard control, consisting of 50 isolates each of S. pneumoniae, S. pyogenes and Haemophilus influenzae, confirmed that azithromycin susceptibility testing resulted in falsely elevated MICs. CONCLUSIONS: Carbon dioxide falsely elevated azithromycin MICs for S. pneumoniae and S. pyogenes, with an apparent reduction in susceptibility. When the in vitro activity of azithromycin and other macrolides against S. pneumoniae and S. pyogenes is being evaluated, awareness of the pH effect is essential.