Plenity: A Capsule for Obesity That’s Really a Device

FDA has just cleared a new capsule for obesity care that doesn’t fit neatly into any of the sorting boxes for obesity treatment. It’s not a drug, even though it looks like one. Instead, it’s a device. It’s a capsule full of hydrogel particles that swell into a mass to help your stomach feel full after you swallow it. Twice a day, you take three of these rather large capsules. Formerly called Gelesis100 capsules, Gelesis will sell the product under the brand name of Plenity.

It will require a prescription and will likely become widely available next year.

Cleared, Not Approved

This is a product with a lot of nuances. FDA cleared it for marketing with a 510(k) review. This process applies to devices that are very similar to products that are already on the market. In the case of Plenity, other hydrogels are on the market, so FDA treats it as nothing new. Compared to a PMA application, the process to get to market was simple.

That’s why you’ll hear Gelesis saying that Plenity is “FDA cleared” and not “FDA approved.” Essentially, FDA says it sees no problems when it approves a 510(k) application. But it doesn’t do the kind of deep review of safety and effectiveness that a PMA requires.

One Six-Month Study

As support for the effectiveness of this device, Gelesis has one six-month, double blind, placebo-controlled study of 436 patients. It worked perfectly well, with Plenity doubling the odds of losing five to ten percent of body weight compared to placebo.

We don’t have long-term data, but there’s no reason to expect it will be terribly different from other treatments. With continued treatment, patients will regain some, but not all, of the weight they lose with most treatments in most studies. When the treatment stops, the weight returns. Obesity is a chronic disease, not a temporary condition.

No Long Term Data or Restrictions

So we have a device that looks like a drug. The body absorbs none of this hydrogel. It just goes right through the body, making you feel fuller while it’s in there. The labeling allows for people to keep using it indefinitely, which makes sense for something to treat obesity.

This mechanism of action is very similar to gastric balloons – but without the balloon. And without the limited duration of use that goes with balloons.

Since it’s not absorbed, the safety is likely pretty good. If you’ve ever taken Gaviscon, then you’ve taken a hydrogel product in a different form and for a different purpose (heartburn).

Bottom line, it’s good to have another option. But we need more data on long-term safety and long-term effectiveness.

Click here for further commentary from Scott Kahan and Vivek Kumbhari. For more information and perspective, click here, here, and here.

Plenity, illustration © Gelesis

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April 16, 2019