A therapeutic agent delivery system that includes a catheter having a proximal end and an opposite distal end. The catheter has a body with a lumen defined therein. The body of the catheter includes a non-bulbous region having a substantially uniform outer diameter and a bulbous region made from an elastically deformable material. While in a first state the bulbous region has a maximum outer diameter greater than the substantially uniform outer diameter of the non-bulbous region; and while in a second state the maximum outer diameter of the bulbous region is reduced relative to that while in the first state.