FDA Approved the First Sirolimus Balloon. A Subgroup Decides Who Buys It.

In 2003 Cordis won the first FDA approval for a sirolimus-eluting coronary stent. Drug-coated stents went on to become what cardiologists reach for when an artery narrows. This week the company collected another first. Selution SLR, a balloon coated with sirolimus, is now approved in the U.S. to treat in-stent restenosis, when an artery narrows again inside a stent placed there earlier. The only other coated balloon approved here for that job, Boston Scientific's paclitaxel-coated Agent, arrived in March 2024. Selution's pitch is that the patient leaves without another layer of metal.

The approval rests on SELUTION4ISR, which randomized 418 patients to the balloon or to standard care. Standard care meant whatever the treating cardiologist would normally do, and 80% of the time that was another drug-eluting stent. At one year, target lesion failure (cardiac death, a heart attack in the treated vessel, or a repeat procedure on the lesion) hit 15.2% of balloon patients and 13.5% of controls. The balloon was allowed to come in up to 10 percentage points worse and still pass as noninferior. It came in 1.7 points worse.

The control arm records the habit Selution has to break. The protocol let cardiologists treat those patients as they normally would, and four times in five they put in another stent. A balloon that asks interventional cardiologists to unlearn their training is a hard sell, and cath lab teams have been placing drug-eluting stents for more than two decades.

What the subgroup says

The FDA weighs the primary endpoint. A cath lab director deciding what to stock reads further down, to the single-layer numbers MedTech Dive reported. In patients whose artery held a single layer of stent, failure ran 14.2% on the balloon and 6.5% on standard care. In those patients the balloon did not meet noninferiority against a stent. At TCT last October, where the data first came out, Sanjit Jolly said on the panel that the wide margin "muddies the waters," and the panel said a head-to-head trial against stents would tell them more.

The approval stands on a legitimate design, and the investigators built the control arm to look like American practice on purpose. That design also sets the limit of the claim. Cordis can say its balloon holds up against what cardiologists usually do. It can't say the balloon holds up against a fresh stent in the simplest restenosis, because there it didn't. Which patient, then, makes a cardiologist leave the stent on the shelf? The case for adding no more metal grows with every stent layer a vessel already carries, so expect the pitch to drift toward patients with two. The published results don't settle the balloon's advantage there. The trial's main comparison ran against usual care across everyone it enrolled.

Pick the patient before the protocol

That comparison was a product decision as much as a statistical one. It fixed which sentence Cordis could take to the FDA, and which question a buyer would still be asking afterward. An industrial robotics startup faces the same trade when it runs its pilot against a plant's average line: it can post a win the plant's best cell would have beaten, and the plant manager will ask about the best cell first.

Cordis is already running its next test. SELUTION4DeNovo, a 960-patient IDE trial in small coronary vessels that have never held a stent, has finished enrolling. Its comparator, and its subgroups, will set what Cordis can claim in those vessels.

Dave Saunders is the founder of Base Reality Group and a Fractional CPO for product companies. He was a founder and operator at Galen Robotics, where the surgical-robotics platform earned FDA De Novo authorization in 2023, and he managed a 35-patent portfolio licensed from Johns Hopkins. He wrote Founders Who Finish and publishes The Build. More about Dave →