Piclamilast (RP 73401), is a selective PDE4 inhibitor. It is comparable to other PDE4 inhibitors for its anti-inflammatory effects. It has been investigated for its applications to the treatment of conditions such as chronic obstructive pulmonary disease, bronchopulmonary dysplasia and asthma. It is a second generation compound that exhibits structural functionalities of the PDE4 inhibitors cilomilast and roflumilast. The structure for piclamilast was first elucidated in a 1995 European patent application. The earliest mention of the name "piclamilast" was used in a 1997 publication.