Pidotimod, an immunostimulant in pediatric recurrent respiratory tract infections: A meta-analysis of randomized controlled trials

Objectives: Recurrent respiratory tract infections (RRTIs) remain a great challenge to pediatricians, because they can increase the risk of various complications and there is no confirmed effective treatment. In the present study, we aimed to assess the effectiveness and safety of pidotimod (PDT), an immunostimulant, in treatment of RRTIs in children aged 14 years and under. Methods: PubMed, EMBASE, Web of Science, Cochrane Library, ClinicalTrials.gov, CBM and CNKI were searched from their inception up to February 2018. All randomized controlled trials (RCTs) using PDT with various treatment durations and enrolling participants < 14 years of age were included in the present review. The interventions were PDT plus conventional treatment (e.g. anti-bacterial and antiviral therapy) or PDT alone versus the conventional treatment plus placebo or conventional treatment alone. Results: A total of 29 RCTs consisting of 4344 pediatric patients were included in this meta-analysis. Ten RCTs were published from Italy, Russia or Greece, and 19 RCTs were published by Chinese groups. However, appropriate randomization methods were only used in 15 trials. Only one study had explicit allocation concealment. Since only eight RCTs were double-blind and placebo controlled, the evidence was not assessed as high quality. The meta-analysis indicates that treatment with PDT resulted in a significant increase in the proportion of participants who had lower RTIs (RR 1.59; 95% CI 1.45-1.74, p < 0.00001) compared with the conventional treatment. PDT could significantly decrease the duration of cough and fever. The number of patients in using antibiotics was also remarkably decreased in the PDT treatment group. Moreover, PDT administration improved the levels of serum immunoglobulin (IgG, IgA, or IgM) and T-lymphocyte subtypes (CD3 +, CD4 +). Besides, PDT administration did not increase the risk of adverse events of any cause (RR = 1.05, 95% CI 0.72-1.54, p = 0.80). Conclusions: PDT showed a good efficacy and safety in treatment of pediatric RRTIs. Further high-quality and large-scale RCTs are still required to provide confirmatory evidence.