Methods and apparatus are provided for delivering drugs, gene vectors, naturally-occurring or synthetic hormones or proteins or other bioactive agents within a patient's vasculature. In a preferred embodiment, the apparatus comprises a material that elutes or secretes a bioactive agent and is held in place within the patient's vessel by an anchor. The material may comprise a biocompatible, and optionally, absorbable matrix, or a culture medium that sustains and nourishes stem cells, spleen cells or pancreatic islets or other beneficial cells. The anchor and material are sized and/or collapsible from a delivery configuration, in which the anchor and material may be delivered into the patient's vasculature within a delivery sheath, to a deployed configuration, wherein the anchor engages an interior wall of the patient's vessel. The apparatus of the invention may be temporarily or permanently implanted, and may in addition self reconfigure after a predetermined period of residency.