A Study Comparing Efficacy, Safety and Tolerability of the Fixed Dose Triple Combination CHF 5993 With the Fixed Dose Dual Combination CHF 1535 in Subjects With COPD

The purpose of this study is to compare CHF 5993 with CHF 1535 in improving lung function, reducing moderate and severe COPD exacerbations, and other clinical efficacy and safety outcomes in the target subject population.

Inclusion Criteria: * Signed and dated written informed consent must be obtained prior to initiating any study-related procedures * Outpatient * Male or female subjects aged ≥40 years * Female subjects: 1. WOCBP fulfilling one of the following criteria: i. WOCBP with fertile male partners: they and/or their partner must be willing to use a highly effective birth control method from the signing of the informed consent form and until the follow-up contact or ii. WOCBP with non-fertile male partners (contraception is not required in this case). 2. Female subjects of non-childbearing potential defined as physiologically incapable of becoming pregnant (i.e. post-menopausal or permanently sterile as per definitions given in Appendix 5). Tubal ligation or partial surgical interventions are not acceptable. If indicated, as per investigator's request, post-menopausal status may be confirmed by follicle-stimulating hormone levels (according to local laboratory ranges) * COPD diagnosis for at least 12 months before the screening visit in accordance with the definition by the GOLD 2020 Report * Current or ex-smokers who quit smoking at least 6 months prior to screening with a smoking history of at least 10 pack-years \[pack-years = (number of cigarettes per day x number of years)/20\] * COPD Assessment Test (CAT) score ≥10 * A pre- and post-bronchodilator FEV1/FVC ratio \3 up to 30 sec\]) 3. Evidence of Mobitz Type II second degree or third-degree atrioventricular block 4. Prolonged QTcF (\>450ms for males, or \>470ms for females). This criterion is not applicable for subjects with a pacemaker or permanent AF. * Clinically significant laboratory abnormalities indicating a significant or unstable concomitant disease which may impact the efficacy or the safety of the study drug according to investigator's judgement * Unstable or uncontrolled concurrent disease which may impact the efficacy or safety of the study drug or the subject's participation in the study according to investigator's judgment * Malignancy that has not been in complete remission for at least 1 year or any untreated localized carcinomas * History of alcohol abuse and/or substance/drug abuse within 12 months prior to the screening visit * Receipt of any other investigational drug within 1 month or 5 half-lives (whichever is greater) prior to the screening visit or have been previously randomized in this trial, or are currently participating in another clinical trial * Currently in the acute phase of a pulmonary rehabilitation program within 4 weeks before the screening visit or planning to enroll in the acute phase of such a program during the study. Subjects who are in the maintenance phase of a pulmonary rehabilitation program are not excluded * Mentally or legally incapacitated, or subjects incarcerated as a result of an official or judicial order * Major surgery in the 3 months prior to the screening visit or have a planned surgery during the trial * Non-satisfactory compliance with the eDiary (\135%) during the run-in period * Subjects requiring the use of spacer device or nebulizer for administration of maintenance COPD therapies. * Veins unsuitable for repeat venipuncture * Blood donation or blood loss (≥450mL) in the 4 weeks before randomization