How does a drug-coated balloon work? Overview about coating technologies and their impact

According to current understanding the drug-coated balloon carries a sufficient dose of an effective antineoplastic agent, i.e. paclitaxel, to the target lesion.

Literature review and report on experimental studies simulating the access of coated balloons to the treatment site and studies in pigs.

The drug adheres to the balloon membrane and is partially hidden below the folds which are wrapped around the shaft. Upon inflation solid paclitaxel particles are pushed into the vessel wall. Premature loss of paclitaxel and transfer to the vessel wall is controlled by the formulation including an inactive additive. Particles in the tissue dissolve slowly resulting in a terminal half-life of almost 2 months. Premature loss of the drug, dissolution, elimination, efficacy and tolerance are limited by the very low solubility of paclitaxel. From exemplary DCB approximately 10% of drug is lost before the target lesion is reached, 5-20% is transferred into the vessel wall and 10% remain on the balloon after withdrawal. The difference is distributed in the general circulation. Inhibition of neointimal proliferation in animal models is reliable and as persistent as with drug-eluting stents. Histology reveals slight to moderate dose-dependent downstream effects without functional or clinical symptoms.

For the time being paclitaxel remains the drug of choice, the dose varies between 2 and 3.5 μg/mm² balloon surface. Neither in animal experiments nor in clinical trials problems have been detected in vessel segments treated with overlapping balloons. Future developments are expected improving efficacy in additional disease conditions (e.g., calcified vessels) and vessel territories.