Prevention of recurrent respiratory tract infections: a literature review of the activity of the bacterial lysate Lantigen B.

Lantigen B, a bacterial lysate, was developed in the 1960s and showed a prophylactic effect in patients with recurrent respiratory tract infections. The objective of this article is to review the literature to update the efficacy and safety profile of Lantigen B in preventing recurrent respiratory tract infections (RRTI). Articles available from international data banks and producing company archives were used. Only clinical studies providing a control group were considered. The effects of Lantigen B on the number of infectious episodes or comparable parameters were analyzed. 22 randomized clinical trials on 4,571 patients published between 1963 and 2014, with different methodologic accuracy, consistently demonstrated that Lantigen B reduced RRTI vs. placebo (RR -0.47; 95% CI = -0.38 to -0.56). The RR always favored Lantigen B in all the other subsets analyzed in adults with RRTI (RR = -0.48; 95% CI = - 0.33 to -0.62) and children (RR = -0.490; 95% CI = - 0.36 to -0.61). Unfortunately, some studies performed in the past evaluated a small number of patients, and clinical procedures were not always performed according to the more recent good clinical practices. Despite these evident limitations of considered studies, the response frequency has remained almost unchanged since the first articles in the 1960s. These data confirm the efficacy of Lantigen B alone in the prophylaxis of acute respiratory infections in adults and children but also suggest that Lantigen B, used with novel therapeutic strategies, can further improve clinical outcomes.