Mucolytic Effectiveness of Tyloxapol in Chronic Obstructive Pulmonary Disease - A Double-Blind, Randomized Controlled Trial

Abstract

Objective: Mucoactive drugs should increase the ability to expectorate sputum and, ideally, have anti-inflammatory properties. The aim of the study was to evaluate the mucolytic activity of Tyloxapol compared to saline (0.9%) in COPD.

Design: A randomized, placebo-controlled, double-blinded crossover, clinical trial was carried out. Patients were randomly assigned to either inhale 5 ml Tyloxapol 1% or saline 0.9% solution three times daily for 3 weeks and vice versa for another 3 weeks. 28 patients (18 male, 10 female, 47 to 73 years old, median age 63.50) were screened, 21 were treated and 19 patients completed the study per protocol.

Results: A comparison of the two treatment phases showed that the primary endpoint sputum weight was statistically significant higher when patients inhaled Tyloxapol (mean 4.03 g, 95% CI: 2.34-5.73 g at week 3) compared to saline (mean 2.63 g, 95% CI: 1.73-3.53 g at week 3). The p-value at three weeks of treatment was 0.041 between treatment arms. Sputum cells decreased during the Tyloxapol treatment after 3 weeks, indicating that Tyloxapol might have some anti-neutrophilic properties. Lung function parameters (FVC, FEV1, RV, and RV/TLC) remained stable during the study, and no treatment effect was shown. Interestingly, there was a mean increase in all inflammatory cytokines (IL-1β, IL-6, and IL-8) during the saline treatment from day 1 to week 3, whereas during the Tyloxapol treatment, all cytokines decreased. Due to the small sample size and the large individual variation in sputum cytokines, these differences were not significant. However, analyses confirmed that Tyloxapol has significant anti-inflammatory properties in vitro. Despite the high number of inhalations (more than 1000), only 27 adverse events (20 during the Tyloxapol and seven during saline) were recorded. Eleven patients experienced AEs under Tyloxapol and six under saline treatment, which indicates that inhalation of saline or Tyloxapol is a very safe procedure.

Conclusion: Our study demonstrated that inhalation of Tyloxapol by patients with COPD is safe and superior to saline and has some anti-inflammatory effects.

Trial registration: ClinicalTrials.gov NCT02515799.

Conflict of interest statement

Competing Interests: The authors of this manuscript have the following competing interests: Stefan Zielen received fees for lectures and advisory boards from the following companies: bene-Arzneimittel GmbH (http://www.bene-arzneimittel.de), Vifor Pharma Deutschland GmbH (http://www.viforpharma.de), Novartis AG (https://www.novartis.com), GlaxoSmithKline GmbH (http://www.glaxosmithkline.de), ALK-Abelló Arzneimittel GmbH (http://www.alk-abello.com), Allergy Therapeutics (http://www.allergytherapeutics.com), Boehringer Ingelheim (https://www.boehringer-ingelheim.de), Allergopharma GmbH (https://www.allergopharma.de) and Biotest (https://www.biotest.com). Martin Rosewich received fees for lectures from the following companies: Novartis AG (https://www.novartis.com), GlaxoSmithKline (http://www.glaxosmithkline.de), Allergopharma GmbH (https://www.allergopharma.de) and Allergy Therapeutics (http://www.allergytherapeutics.com). This does not alter the authors' adherence to PLOS ONE policies on sharing data and materials.

Figures

Fig 1. Study design.

Phase A patients were treated with either Tyloxapol or saline for 21 days at three inhalations a day. After a wash-out phase of 7 days, Phase B started. Patients were switched to the other medication for another 21 days.

Fig 2. Patient flow chart.

28 patients were initially enrolled, 21 completed visit 1 and started treatment phase, 19 finished the study, 2 dropped out because of the following: intestinal bleeding (n = 1) and difficulties to inhale due to shortness of breath (n = 1).

Fig 3. Sputum weight before processing comparing Tyloxapol and saline.

The figures illustrate (A-C) the sputum weight of patients treated with Tyloxapol and saline before further processing at (A) day 1 (n = 19 vs. 18), (B) 1 week (n = 19 vs. 17) and (C) 3 weeks of inhalation (n = 18 vs. 16), and (D) the fitted mixed linear model for the weight of sputum secretion [g]. The black lines represent the predicted mean of each therapy arm. The grey lines represent the observed values by each test person at day 1, 7 and 21. *, p

Fig 4. Sputum weight and cells comparing smokers and non-smokers during treatment with Tyloxapol and saline.

(A, C and E) represent the Tyloxapol group, and (B, D and F) represent the saline group. (A-B) Sputum weight before processing. (C-D) the total cells and (E-F) the neutrophils. Sample size: A: n = 36 vs. 20, B: n = 33 vs. 18, C: n = 24 vs. 13, D: n = 22 vs. 12, E: n = 23 vs. 11, F: n = 22 vs. 9. Graphs show the pooled patients at all 3 visits and are separated by smoking status. Bars represent the median. ** p

Fig 5. Cytokine release after macrophage activation test.

(A-D) Cytokine release, after 24-hr LPS-stimulation of whole blood cells incubated with different concentrations of Tyloxapol in vitro as measured by the CBA. * p < 0.05; ** p < 0.01; *** p < 0.001.

Fig 6. Effect of Tyloxapol on cell viability.

Cell viability of LPS treated whole blood cells in the presence of different concentrations of Tyloxapol (0, 0.001, 0.01, 0.1, 1.0 mg/ml) compared with hypertonic saline (3.0, 7.0%) after 24 hours was measured by 7AAD-staining using flow cytometry. (A-D) Histograms of flow cytometric analysis. (E) Quantitative analysis of four independent analysis. ** p