Use of a polyvalent bacterial lysate in patients with recurrent respiratory tract infections: results of a prospective, placebo-controlled, randomized, double-blind study.

Respiratory tract infections (RTIs) are the most common infections in humans, and it is difficult to effectively treat patients with increased susceptibility to these ailments. LW 50020 (Luivac; Paspat oral), an oral immunomodulator consisting of the antigens of seven bacteria commonly involved in RTIs, has been developed for the induction of specific and nonspecific immune responses of the mucosa-associated lymphoid tissue. In this placebo-controlled study, the efficacy and safety of the tablet formulation of LW 50020 were evaluated in children and adults with recurrent RTIs. Tablets were taken once daily during two periods of 4 weeks each, interrupted by a treatment-free interval of 4 weeks. The main endpoint of the study, a clinical severity score that evaluated treatment benefits, was significantly lower in the second study period in patients treated with the bacterial lysate compared to patients given placebo. A comparison of the infection rates in the first and second study periods of patients treated with LW 50020 revealed a placebo-corrected reduction of 39% in children and a placebo-corrected reduction of 44% in adolescents and adults. The placebo-corrected duration of infections was shortened by 47% in children and by 55% in older patients. No serious drug-related side effects occurred. This study demonstrated that the oral bacterial immunomodulator LW 50020 is efficacious in treating patients with recurrent RTIs.