Ensifentrine (RPL554) for increasing trough lung function in COPD

A method of treating chronic obstructive pulmonary disease (COPD), wherein the method increases trough lung function in a human subject having COPD, the method comprising administering to the human subject via inhalation two or more doses per day of a composition comprising a therapeutically effective amount of ensifentrine or a pharmaceutically acceptable salt thereof for at least 12 weeks, wherein following the at least 12 weeks the trough lung function is increased by at least about 40 mL as determined by FEV1 of the human subject about 11.5 hours to about 12 hours following a prior administration of the composition compared to FEV1 of the human subject prior to a first administration of the composition to the human subject, wherein the composition is for maintenance treatment of COPD, wherein the therapeutically effective amount of the ensifentrine or the pharmaceutically acceptable salt thereof is 2 mg to 4 mg based on ensifentrine free base weight and the composition is a suspension comprising:

• a. ensifentrine particles at a concentration of from 1 to 1.4 mg/mL;
• b. polysorbate 20 at a concentration of from 0.3 to 0.7 mg/mL;
• c. sorbitan monolaurate at a concentration of from 0.0 to 0.1 mg/mL;
• d. sodium dihydrogen phosphate dihydrate at a concentration of from 0.5 to 1 mg/mL;
• e. disodium hydrogen phosphate dihydrate at a concentration of from 0.5 to 1 mg/mL;
• f. sodium chloride at a concentration of from 5 to 10 mg/mL;
• and
• g. water.