Combined drug delivery methods and apparatus

A therapeutic device to treat an eye, the device comprising:

• a rigid-walled housing having a substantially fixed volume during implantation and use, wherein the housing is sized to extend through the sclera into the vitreous humor when the device is implanted in the eye;
• a first chamber located within the housing and configured to hold a first therapeutic agent, the first chamber having a first rigid, porous structure positioned at a distal end region of the first chamber;
• and
• a second chamber located within the housing and configured to hold a second therapeutic agent, the second chamber having a second rigid, porous structure positioned at a distal end region of the second chamber;
• wherein at least one of the first and second chambers is refillable, and wherein the first and second rigid, porous structures each have a plurality of interconnecting, irregularly-shaped channels.