Implantable device for sustained release of a macromolecular drug compound

An implantable device for delivery of a macromolecular drug compound, the device comprising:

• a core having an outer surface, wherein the core comprises a core polymer matrix within which is dispersed a drug compound having a molecular weight of about 5 kDa or more, the polymer matrix containing a first ethylene vinyl acetate copolymer;
• and a membrane layer positioned adjacent to the outer surface of the core, wherein the membrane layer comprises a membrane polymer matrix within which the macromolecular drug compound is optionally dispersed, wherein the concentration of the macromolecular drug compound in the core is greater than the concentration of the macromolecular drug compound in the membrane layer, the membrane polymer matrix comprising a second ethylene vinyl acetate copolymer, wherein the second ethylene vinyl acetate copolymer constitutes from about 70 wt. % to about 99 wt. % of the membrane layer, and wherein the implantable device has a release rate between 0.1E+0 and 0.5E+2 μg per hour for a time period up to about 1500 hours.