AIM:To investigate moxifloxacin-containing triple therapy as second-line treatment for Helicobacter pylori(H.pylori)infection following failed first-line treatment.METHODS:The sample included 312 patients for whom first-line treatment failed between January 2008and May 2013;27 patients were excluded,and a total of 285 patients received 7-or 14-d moxifloxacincontaining triple therapy as second-line treatment for H.pylori infection.First line regimens included 7-d standard triple(n=172),10-d bismuth-containing quadruple(n=28),14-d concomitant(n=37),or14-d sequential(n=48)therapy.H.pylori status was evaluated using 13C-urea breath testing 4 wk later,aftercompletion of the treatment.The primary outcome was the H.pylori eradication rate analyzed using intentionto-treat(ITT)and per protocol(PP)analyses.The secondary outcome was the occurrence of serious adverse events.Demographic and clinical factors were analyzed using Student’s t-tests and Pearson’sχ2 tests according to first-and second-line regimens.A P value of less than 0.05 was considered statistically significant.RESULTS:The eradication rate of moxifloxacincontaining triple therapy was 68.4%(ITT;95%CI:62.8-73.5)and 73.9%(PP;95%CI:68.3-78.8).The eradication rate was significantly higher with 14 d compared to 7 d of treatment(77.5%vs 62.5%,P=0.017).Peptic ulcer patients had a higher eradication rate than the patients without ulcers(82.9%vs 70.6%,P=0.046).The demographic and clinical characteristics were not significantly different between the groups according to first-line therapies.ITT and PP analyses of the moxifloxacin-containing triple therapy indicated the following eradication rates:70.9%(95%CI:63.8-77.2)and 77.2%(95%CI:70.1-83.1)for standard triple;67.9%(95%CI:51.5-84.2)and 67.9%(95%CI:51.5-84.2)for bismuth-containing quadruple;60.4%(95%CI:46.3-73.0)and 70.7%(95%CI:54.0-80.9)for sequential;and 67.6%(95%CI:51.5-80.4)and67.6%(95%CI:51.5-80.4)for concomitant therapy.There were no statistically significant differences in the efficacy of the first-line regimens(P=0.492).The most common adverse event was diarrhea.There were no serious adverse events and no significant differences in the frequency of side effects between the first-and second-line regimens(28.7%vs 26.1%,respectively).CONCLUSION:Moxifloxacin-containing triple therapy as second-line treatment resulted in low eradication rates.There were no differences in the efficacy between the first-line regimens in South Korea. AIM: To investigate moxifloxacin-containing triple therapy as second-line treatment for Helicobacter pylori (H. pylori) infection following failed first-line treatment. METHODS: The sample included 312 patients for whom first-line treatment failed between January 2008 and May 2013; 27 patients were excluded and a total of 285 patients received 7-or 14-d moxifloxacincontaining triple therapy as second-line treatment for H. pylori infection. First line regimens included 7-d standard triple (n = 172), 10-d bismuth-containing quadruple (n = 28), 14-d concomitant (n = 37), or14-d sequential (n = 48) therapy. H. pylori status was evaluated using 13 C-urea breath testing 4 wk later, after complex of the treatment. the primary outcome was the H. pylori eradication rate analyzed using intention to-treat (ITT) and per protocol (PP) analyzes. The secondary outcome was the occurrence of serious adverse events. Demographic and clinical factors were analyzed using Student’s t-tests and Pearson’s x2 tests according to first-and seco nd-line regimens. AP value of less than 0.05 was compared significant significant .RESULTS: The eradication rate of moxifloxacin con- escition triple therapy was 68.4% (ITT; 95% CI: 62.8-73.5) and 73.9% (PP; 95% CI: 68.3 -78.8). The eradication rate was significantly higher with 14 d compared to 7 d of treatment (77.5% vs 62.5%, P = 0.017) .Peptic ulcer patients had a higher eradication rate than the patients without ulcers (82.9% vs 70.6% , P = 0.046). The demographic and clinical characteristics were not significantly different between the groups according to first-line therapies. ITT and PP analyzes of the moxifloxacin-containing triple therapy showed the following eradication rates: 70.9% (95% CI: 63.8 67.9% (95% CI: 51.5-84.2) and 67.9% (95% CI: 51.5-84.2) for bismuth-containing quadruple; 60.4% (95% CI: 46.3-73.0) and 70.7% (95% CI: 54.0-80.9) for sequential; and 67.6% concomitant therapy.There are no pure significant di fferences in the efficacy of the first-line regimens (P = 0.492). The most common adverse event was diarrhea.There were no serious adverse events and no significant differences in the frequency of side effects between the first- and second-line regimens ( 28.7% vs 26.1%, respectively) .CONCLUSION: Moxifloxacin-containing triple therapy as second-line treatment resulted in low eradication rates. Here are no differences in the efficacy between the first-line regimens in South Korea.