In a 4-week crossover study in 38 patients with COPD, roflumilast 500μg daily significantly reduced sputum absolute neutrophil count, IL-8 and neutrophil elastase compared with placebo treatment. Interestingly, the mechanism of anti-neutrophilic inflammation with roflumilast treatment in patients with COPD was recently found to be mediated through decreasing prolyl endopeptidase activity and acetyl-proline-glycine-proline (AcPGP), thus providing a clear biological plausibility for clinical activity of roflumilast. The clinical benefits of roflumilast treatment in COPD were subsequently demonstrated in 2 identical RCTs involving 3,096 patients with COPD having severe airflow limitation and history of exacerbations. Treatment with roflumilast 500μg daily resulted in better prebronchodilator FEV1 (by 48 ml in 52 weeks) and lower rate of exacerbations (reduction by 17%) compared with placebo treatment. The benefit of roflumilast on lung function has also been confirmed in another 2 identical RCTs among those patients with moderate to severe COPD already treated with long-acting bronchodilators (salmeterol or tiotropium). The mean pre-bronchodilator FEV1 was significantly improved with roflumilast compared to placebo treatment for 24 weeks by 49ml and 80ml respectively in patients with COPD already treated with salmeterol and tiotropium respectively. More recently, among patients with more severe COPD requiring combination ICS/long-acting β2 agonist, roflumilast treatment for 52 weeks significantly reduced the rate of moderate-to-severe exacerbations by 13.2% compared to placebo group. The safety and adverse effects of roflumilast have been well-tolerated, resulting in worldwide (including Hong Kong) approval for clinical use in COPD. The common adverse effects of roflumilast treatment include weight reduction (\>10% loss in 7% subjects), decreased appetite (2%), insomnia (2%), headache (4%), diarrhea (10%) and nausea (5%).

Our group has previously embarked on various clinical studies in non-CF bronchiectasis: a 4-week treatment of inhaled fluticasone (ICS) compared with placebo (1), a subsequent 52-week randomized controlled trial of inhaled fluticasone in 86 patients (4), and a separate study on sputum elastase in 30 patients (2). These support the feasibility of conducting similar clinical trials, like the current proposal, on non-CF bronchiectasis in our unit. To prepare for the current study proposal, we have conducted a pilot and feasibility study of 4-week treatment of roflumilast in stable-state non-CF bronchiectasis with the exact inclusion/exclusion criteria as the current proposal (HKU/HA HKW IRB approval no. UW 17-444) since March 2018. Up to January 2019, we have successfully recruited 15 eligible study subjects. The initial study protocol mandated the starting dose of roflumilast at 500 microgram daily. The first two study subjects experienced intolerable gastrointestinal side effects within 1-2 weeks of treatment, leading to premature treatment cessation. An amended study protocol (HKU/HA HKW IRB approval dated 24 July 2018) was approved that allowed a lower initiating dose of 250 microgram daily, which is in line with the current recommended prescription in COPD patients. Nine out of the subsequent 13 subjects (including the most recent 8 subjects consecutively) were able to complete roflumilast 250 microgram daily treatment for a total of 4 weeks, with less than grade 1 toxicities. The characteristics of the nine per-protocol study subjects include: M:F=4:5, age of 69.9 ± 9.1 years (mean ± SD) and baseline 24-h sputum volume of 30.00 ± 26.93 ml (for all 15 subjects: 27.47 ± 22.59 ml). The preliminary results showed insignificant change in sputum volume and a trend of reduced sputum IL-1β (pre- vs post-treatment: 10.84 vs 2.63 ng/ml, p=0.102). This indicates a possible anti-inflammatory effect of roflumilast in non-CF bronchiectasis with just 4 weeks of treatment, though this pilot was meant for feasibility study and not powered to detect significant change. The true benefit will likely require a longer duration of treatment (thus proposing 12 weeks in this study) with sufficient sample size.

This study aims to investigate the effect of 12-week treatment with roflumilast on neutrophilic airway inflammation in stable-state non-CF bronchiectasis. The primary outcome measure is 24-h sputum volume. The extent of airway inflammation in non-CF bronchiectasis is indicated by sputum leukocyte density, pro-inflammatory cytokines (IL-1β, IL-8, TNF-alpha, LTB4 and IL-17) and neutrophil elastase. Health-related quality of life (HRQoL) is a key secondary outcome. We hypothesize that 12-week treatment of roflumilast in stable-state non-CF bronchiectasis can result in: (1) reduction in 24-h sputum volume (primary hypothesis); (2) reduction in sputum leukocyte density; (3) reduction in sputum pro-inflammatory cytokines (IL-1β, IL-8, TNF-alpha, and IL-17) and LTB4; (4) reduction in sputum neutrophil elastase; (5) no change in sputum bacterial colonization and load; (6) improvement in HRQoL.