Abstract: Biodegradable controlled release agent implants and methods of making and using thereof, are preferably formed of poly(?-pentadecalactone-co-p-dioxanone) [poly(PDL-co-DO)] or poly(ethylene brassylate-co-dioxanone), a family of polyester copolymers that degrade slowly in the presence of water. The material is suitable as the basis of a biodegradable controlled agent release implant that provides sustained release of a therapeutic such as an antiviral, thereby significantly increasing patent compliance and efficacy. Results show long term co-administration of agents having greater than additive efficacy. The implant may be inserted subcutaneously, allowing degradation over a period of up to about 18 or 24 months, eliminating the need for removal by a trained practitioner.