Ensifentrine (MK-5884) Study for the Prevention of Chronic Obstructive Pulmonary Disease (COPD) Exacerbations in Adults With a History of Moderate or Severe Exacerbations While Receiving Standard of Care (SOC) (MK-5884-031/RPL554/ENHANCE-3)

Inclusion Criteria:

Inclusion Criteria include but are not limited to:

* Has a diagnosis of Chronic Obstructive Pulmonary Disease (COPD) that was made ≥12 months prior to randomization
* Has been on the stable treatment with the same standard of care (SOC) with long-acting muscarinic antagonist (LAMA)/long-acting beta-2 agonist (LABA)/inhaled corticosteroid (ICS) or LAMA/LABA (if ICS is not appropriate), for at least 2 months prior to Screening
* Has a documented history of ≥1 moderate or severe COPD exacerbation while on standard of care (SOC) within 1 year of Screening
* Is a current or former cigarette smoker with a history of cigarette smoking ≥10 packyears at Screening (number of pack-years = \[number of cigarettes per day/20\] × number of years smoked \[e.g., 20 cigarettes per day for 10 years, or 10 cigarettes per day for 20 years\]). Pipe, cigar, and/or e-cigarette/vape use cannot be used to calculate pack-year history.
* Has post-bronchodilator forced expiratory volume 1 (FEV1) ≥25% and \<70% of Predicted Normal Value

Exclusion Criteria:

Exclusion criteria include but are not limited to:

* Has a history of intubation for respiratory failure within 1 year of Screening
* Is receiving long-term oxygen therapy defined as \>15 hours per day
* Uses chronic bilevel positive airway pressure for treatment of respiratory condition unless for treatment of sleep apnea at a stable pressure for at least 3 months
* Is currently using or has used a biologic therapy (e.g., dupilumab, mepolizumab, or tozorakimab) within 6 months prior to Screening Visit
* Has history of or current malignancy of any organ system, treated or untreated within the past 5 years, except for localized basal or squamous cell carcinoma of the skin.