ALDH7A1 and chronic obstructive pulmonary disease: Additionally, two novel PDE inhibitors, ensifentrine, and tanimilast, are currently in clinical trials for COPD and asthma; ClinicalTrials.gov records mention two Recruiting Phase 3 studies of tanimilast in COPD (NCT04636814, NCT04636801), while ensifentrine is in two Ongoing Phase 3 trials in COPD and a Phase 2 study in asthma that has shown a dose-dependent bronchodilation similar to salbutamol, but without impacting potassium levels and having a less significant impact on heart rate and pulse rate (Bjermer et al., 2019).