The therapeutic efficacy of erdosteine in the treatment of chronic obstructive bronchitis: a meta-analysis of individual patient data

Erdosteine, a drug approved for the treatment of acute and chronic pulmonary diseases, has been shown to be an effective treatment for chronic bronchitis or COPD (CB/COPD) in several studies, although marked differences in the perception of its usefulness still remain.

Aim: to test the available evidence for the efficacy of erdosteine in adults with stable or exacerbated CB/COPD.

Methods: Meta-analysis of individual patient data from both published and unpublished randomized controlled trials (RCTs) comparing erdosteine with placebo/mucolytics, given for up to 10 days in association with standard therapy (RCTs used for regulatory drug approval). Individual patient data were provided by the manufacturer of erdosteine, Edmond Pharma (Milano, Italy). Endpoints were symptom scores (cough frequency and intensity, sputum viscosity and purulence, difficulty to expectorate, catarrh rhonchi at auscultation, dyspnoea), a cumulative global efficacy index (cGEI), and an overall physician efficacy assessment (OA).

Results: individual data from 1046 patients from 15 RCTs (12 on exacerbated and 3 on stable CB/COPD) were obtained. Erdosteine induced a significant reduction of cGEI vs comparators (-1.02; 95% CI: from -1.60 to -0.44; p=0.0006), both placebo and mucolytics. On individual symptoms, it positively impacted on cough frequency (-0.19; 95% CI: from -0.34 to -0.03) and intensity (-0.30; 95% CI: from -0.44 to -0.17), sputum viscosity (-0.28; 95% CI: from -0.49 to -0.07), difficulty to expectorate (-0.24; 95% CI: from -0.40 to -0.08), and catarrh ronchi at auscultation (-0.35; 95% CI: from -0.60 to -0.10). The effects on dyspnoea were only significant vs placebo, whereas sputum purulence was not significantly modified. The OA also favoured erdosteine, doubling the chance of success compared with placebo and mucolytics: OR (odds ratio) 2.06; (95% CI: from 1.27 to 3.33). The treatment with erdosteine was well tolerated. Adverse events, mainly gastrointestinal, were reported by 10.2% of patients compared to 11.0% in the reference groups.

Conclusions: Treatment with erdosteine is associated with a significant benefit in terms of symptom amelioration both vs placebo and mucolytics in patients with CB/COPD. Although with some limitations (e.g. not fully validated scores) this review reinforces the use of erdosteine, in combination with standard therapy, in respiratory diseases characterized by increased expectoration, namely acute CB/COPD exacerbations.