A Study to Investigate Using Inhaled Fexlamose to Treat Adult Participants Who Have Moderate to Severe COPD

Main Inclusion Criteria Each participant must meet all the following criteria to be enrolled in this study: * Participant is male or female ≥40 to ≤80 years of age. * Participant has a verified diagnosis of cigarette smoking-related COPD FEV1 that is \>25% and \<60% of predicted normal at Visit 1. * Participant meets the following spirometry performance criteria: * Acceptability: Participant can perform acceptable spirometry (ie, meet ATS/ERS acceptability criteria) at Visits 1 and 2. * Repeatability: Participant can perform technically acceptable spirometry meeting repeatability criteria for FEV1 during at least 1 of the prebronchodilator assessments at Visits 1 and 2. * Participant is on stable maintenance COPD medications with no dose adjustments for ≥4 weeks prior to Screening and during the Screening Period. * Participant has had ≤2 COPD exacerbations requiring hospitalization in the past year. Main Exclusion Criteria Participants meeting any of the following criteria will be excluded from the study: * Participant has an active uncontrolled medical condition * Participant has a diagnosis of current asthma * Participant has primary diagnosis of bronchiectasis, primary ciliary dyskinesia, allergic bronchopulmonary aspergillosis, or CF. * Participant has had a COPD exacerbation in the 6 weeks prior to Visit 1 * Participant has active lung infection * Participant has received any vaccine within 7 days prior to Day 1. * Participant is taking a protein therapeutic for control of COPD or asthma: eg, dupilumab, tezepelumab, benralizumab, mepolizumab, omalizumab.