Disclosed herein are implantable medical devices having controlled release biodegradable polymer coatings thereon wherein the polymer is formed from ring opening of γ-butyrolactone and at least one additional monomer selected from the group consisting of trimethylene carbonate, lactide, polyethylene glycol, glycolide, the monomers formed from ring opening of ε-caprolactone, 4-tert-butyl caprolactone, and N-acetyl caprolactone, and combinations thereof, and at least one drug releasable from the biodegradable polymer. Also disclosed are implantable medical devices form of the biodegradable polymers and processes for forming the polymers.