Boston Scientific recently announced a clinical trial of its AGENT drug coated balloon. The device is coated with paclitaxel, an anti-restenotic drug, and aims to deliver the medication to the affected vessel wall during a percutaneous procedure. Coronary in-stent restenosis (ISR) is caused by occlusive scar tissue that develops in the stented portion of a vessel.
At present, ISR is treated through the addition of extra stents and radiation therapy is also sometimes used. Both of these approaches pose safety risks for patients. Balloon angioplasty represents an alternative approach, but is not always successful, with mixed or modest efficacy. This latest technology aims to enhance the efficacy of balloon angioplasty in ISR by combining it with localized drug delivery to the vessel wall.
The balloon opens the occluded vessel and then delivers paclitaxel to the vessel wall to help reduce stenosis. Boston Scientific recently began the AGENT IDE clinical trial to test the safety and efficacy of the device. Medgadget had the opportunity to speak with Ian Meredith, M.D., Global Chief Medical Officer at Boston Scientific, about the technology.
Conn Hastings, Medgadget: Please tell us about coronary in-stent restenosis and how the condition is currently treated.
Dr. Ian Meredith, Boston Scientific: In-stent restenosis (ISR) refers to the growth of scar tissue over time inside the stented section of a coronary artery. This scar tissue eventually obstructs blood flow in the artery causing symptoms similar to the narrowing that was initially treated with a stent. While coronary stenting continues to show a substantial improvement in quality of life for patients with coronary artery disease, ISR can occur occasionally.
ISR occurs after percutaneous coronary interventions (PCIs) in approximately 10% of cases. Current treatment practices include simple balloon dilatation commonly referred to as “plain old” balloon angioplasty (POBA), insertion and layering of additional stents, or radiation. Both a second layer of stents and radiation introduce potential safety risks to patients.
Medgadget: Please give us an overview of the AGENT Drug-Coated Balloon and how it works.
Dr. Meredith: The AGENT DCB is a percutaneous transluminal coronary angioplasty (PTCA) balloon catheter that is coated with an anti-restenotic drug and delivered to the affected vessel wall via a proprietary coating technology. Granted Breakthrough Device designation by the FDA earlier this year, it is designed to open narrowed vessels and help treat and reduce ISR reoccurrence.
Medgadget: How does the balloon transfer drug to the vessel wall and enable sustained efficacy? Is the drug encapsulated in a delivery material, such as a hydrogel, or a nanoparticle?
Dr. Meredith: The excipient (carrier) in the coating has unique properties that allow it to maintain its integrity while efficiently transferring a low therapeutic drug dose to the tissue. This results in a low systemic drug exposure for patients.
Medgadget: How does the Agent drug coated balloon improve on current treatment options?
Dr. Meredith: Current treatment strategies for ISR include POBA of the scar tissue which is modestly and inconsistently effective or repeated insertion of additional stents, or radiation. Adding extra stents or using radiation treatment can lead to potential safety risks.The AGENT DCB was designed in response to feedback from physicians that they needed a metal-free and radiation free treatment alternative for their patients with coronary ISR that would result in a predictable and durable effect. AGENT delivers the anti-restenotic drug paclitaxel to the vessel wall without the need for another permanent stent implant.
Medgadget: Please give us an overview of the upcoming AGENT IDE trial.
Dr. Meredith: The AGENT IDE study is the first clinical trial of a coronary drug-coated balloon (DCB) in the U.S. and will evaluate the safety and effectiveness of the AGENT DCB for the treatment of coronary ISR. This prospective, randomized study will compare ISR treatment with the AGENT DCB to treatment with an uncoated balloon (POBA). The study will evaluate the 12-month target lesion failure rate, defined as myocardial infarction related to the target vessel, the need for a revascularization procedure or cardiac mortality. At least 480 patients will be enrolled in the study at 40 U.S. sites.
*The Agent DCB is an investigational device in the US and is not available for sale.
More about the AGENT balloon: