Clarithromycin or levofloxacin in the sequential therapy for H. pylori eradication? authors’ reply

Sirs, We thank Zullo et al.1 for their five useful observations on our article.2 However, we believe there has been a misunderstanding as no result from our study suggests that levofloxacin-based regimens achieved higher eradication rates than clarithromycin sequential therapy. The conclusions in the abstract state that clarithromycin sequential and both levofloxacin regimens were significantly better than triple standard therapy, regardless of their suboptimal efficacy. The figures in the results section do not show differences between clarithromycin and levofloxacin regimens. In the discussion, clarithromycin sequential therapy is defined as suboptimal [intention-to-treat (ITT) eradication rate <80%], whereas levofloxacin-based regimens are defined as adequate, but poor (ITT eradication rate 80–85%), in accordance with current standards.3 According to this definition, one cannot declare that one is better than the other. We also discuss that the fact that cure rates obtained with levofloxacin regimens in Spain are the worst reported in literature (72–82%) is possibly related to a higher levofloxacin resistance than the generally reported (1.8–6%). As such, levofloxacin-based regimens are finally recommended to be saved for second and third-line therapies, owing to their relatively poor efficacy and higher cost. Likewise, we would like to reflect on data published in abstract form of an interesting study from Italy, the same setting as that in the study of Zullo et al., which will be soon presented during 2010 Digestive Diseases Week.4 This study compares 10-day sequential therapy (proton pump inhibitor, amoxicillin and tinidazole) using clarithromycin (CLA-ST), levofloxacin 250 mg b.d. (LEV250-ST) and levofloxacin 500 mg b.d. (LEVO500-ST) with a priori similar antibiotic resistance rate than in Spain (clarithromycin 20%, levofloxacin 3%). ITT cure rates for LEV500-ST (97%) and LEV250-ST (95%) were significantly higher (P < 0.001) than for CLA-ST (80%). Thus, contrary to the line of argument of Zullo et al., this study suggests that levofloxacin sequential therapy can theoretically be an effective first-line regimen close to 100% efficacy (point 1), using tinidazole instead of metronidazole (point 2), significantly better than clarithromycin sequential therapy (point 3), extrapolable to Italy (point 4) and probably cost-effective (point 5) (considering not only the tablets cost but also medical resources saved with such an effective therapy). In conclusion, the high variability of antibiotic resistance for H. pylori, even within the same geographical area, will be probably a key to decide which is the most accurate eradication first-line therapy in each individual setting. In this regard, further studies are needed to establish what is to be done when clarithromycin sequential therapy is suboptimal. Declaration of personal and funding interests: None.