The present disclosure is directed to a catheter for site-specific delivery of a therapeutic agent to a blood vessel of a patient. The catheter further includes an elongated shaft having at least one inner lumen, a distal end and a proximal end and proximal and distal vessel-conforming balloons where each is separately positionable and inflatable, and when inflated, substantially restricts blood flow in the vessel and creates a treatment window of a defined but variable length for delivery of the therapeutic agent. The catheter optionally includes at least one marker band adjacent to the proximal balloon and at least one marker band adjacent to the distal balloon. At least one lateral aperture positioned in the window is in fluid communication with a drug delivery conduit located within either the inner shaft or the outer shaft to provide a homogeneous concentration of the therapeutic agent to the window.
