Esomeprazole magnesium, amoxicillin, and clarithromycin triple therapy has been shown to be active against most strains of and in clinical infections [ Helicobacter pylori (H. pylori) in vitrosee Indications and Usage ( ) and Clinical Studies ( )]. 114

Susceptibility testing of isolates was performed for amoxicillin and clarithromycin using agar dilution methodology, and minimum inhibitory concentrations (MICs) were determined. Helicobacter pylori:H. pylori

Clarithromycin pretreatment resistance rate (MIC ≥ 1 mcg/mL) to was 15% (66/445) at baseline in all treatment groups combined. A total of > 99% (394/395) of patients had isolates that were considered to be susceptible (MIC ≤ 0.25 mcg/mL) to amoxicillin at baseline. One patient had a baseline isolate with an amoxicillin MIC = 0.5 mcg/mL. Pretreatment Resistance:H. pyloriH. pyloriH. pylori

The baseline clarithromycin susceptibility results and the eradication results at the Day 38 visit are shown in Clarithromycin Susceptibility Test Results and Clinical/Bacteriologic Outcomes:H. pyloriH. pyloriTable 8:

Table 8: Clarithromycin Susceptibility Test Results and Clinical/Bacteriological Outcomes for Triple Therapy - (Esomeprazole magnesium 40 mg once daily/amoxicillin 1000 mg twice daily/clarithromycin 500 mg twice daily for 10 days) a

Includes only patients with pretreatment and post-treatment clarithromycin susceptibility test results a

Susceptible (S) MIC ≤ 0.25 mcg/mL, Intermediate (I) MIC = 0.5 mcg/mL, Resistant (R) MIC ≥ 1 mcg/mL b

Patients not eradicated of following esomeprazole magnesium /amoxicillin/clarithromycin triple therapy will likely have clarithromycin resistant isolates. Therefore, clarithromycin susceptibility testing should be done, when possible. Patients with clarithromycin resistant should not be re-treated with a clarithromycin-containing regimen. H. pyloriH. pyloriH. pylori

In the esomeprazole magnesium/amoxicillin/clarithromycin clinical trials, 83% (176/212) of the patients in the esomeprazole magnesium/amoxicillin/clarithromycin treatment group who had pretreatment amoxicillin susceptible MICs (≤ 0.25 mcg/mL) were eradicated of , and 17% (36/212) were not eradicated of . Of the 36 patients who were not eradicated of on triple therapy, 16 had no post-treatment susceptibility test results and 20 had post-treatment isolates with amoxicillin susceptible MICs. Fifteen of the patients who were not eradicated of on triple therapy also had post-treatment isolates with clarithromycin resistant MICs. There were no patients with isolates who developed treatment emergent resistance to amoxicillin. Amoxicillin Susceptibility Test Results and Clinical/Bacteriological Outcomes:H. pyloriH. pyloriH. pyloriH. pyloriH. pyloriH. pyloriH. pylori

For susceptibility testing information about see Microbiology section in prescribing information for clarithromycin and amoxicillin. Susceptibility Test for Helicobacter pylori:Helicobacter pylori,

Decreased gastric acidity due to any means, including proton pump inhibitors, increases gastric counts of bacteria normally present in the gastrointestinal tract. Treatment with proton pump inhibitors may lead to slightly increased risk of gastrointestinal infections such as and and possibly in hospitalized patients. Effects on Gastrointestinal Microbial Ecology:SalmonellaCampylobacterClostridium difficile