Obesity is a disease that currently affects our population in epidemic proportions, and which has a profound effect on health and quality of life. As a physician dedicated to the prevention and treatment of the medical complications of excess weight, I frequently see patients whose efforts at restricting calories and increasing physical activity are not resulting in sustained weight loss.
When that’s the case, particularly if the excess weight is causing health issues, we can consider adding other treatment tools, which include weight loss medications, or weight loss surgeries. And while these options have increased dramatically over the last one to two decades, we still desperately need more treatments, as neither medications nor surgery are accessible or appropriate for every individual affected by obesity.
What is Plenity?
Gelesis100 (Plenity), just approved by the Food and Drug Administration in April and expected to come on the market later this year, is an exciting recent innovation in weight management. Although Plenity comes in capsule form, it is actually a weight loss device, not a medication. The capsules are filled with hydrogel particles. When taken with a full glass of water before meals, the particles expand in the stomach and take up space, leading to the sensation of fullness. The gel particles eventually move through the intestinal tract, and are broken down by enzymes and excreted.
In the pivotal randomized, double-blind, placebo-controlled clinical trial about 60% of those who followed a diet and exercise plan plus took Plenity lost 5% or more of their initial weight. And about 25% of those who took it were high responders, losing 10% or more of initial weight. Average weight loss was modest: -6.4% for the Plenity group vs -4.4% for the control group. (Of note, the desired endpoint of achieving at least 3% more weight loss in the Plenity group compared to the control group was not met.)
Who might benefit from Plenity?
Given the modest weight loss effects, Plenity will not be the cure to the obesity epidemic. And for people with significant weight to lose, it may not help enough.
Even so, I am enthusiastic about the approval of Plenity as the first treatment of its kind for overweight and obesity, because of how it will fit into the landscape of weight reduction treatments. Plenity is approved for use not only in those with obesity (defined as a body mass index [BMI] above 30) but also in people who are overweight (starting at a BMI of 25). This means that a broader population might be eligible to use Plenity compared to weight loss medications, which are approved for people with a BMI above 30, or a BMI above 27 with certain medical conditions, such as type 2 diabetes.
Access for those who have overweight, but who would not be eligible for pharmacologic (or surgical) treatments, could be incredibly impactful. Not only is close to 40% of the world population in the overweight range, but weight loss at lower BMI can help prevent future weight-related health problems.
What else do I need to know about this new weight-loss device?
There were few safety concerns in the clinical trial of Plenity; in fact, no treatment-related serious adverse events occurred. In addition, Plenity is not absorbed into the body at all. As a result, there is little reason to worry about pharmacologic side effects, or interactions with other medications, both of which frequently limit people’s ability to use weight-loss drugs.
This treatment approach also holds promise for future incremental innovations. For example, the in-the-pipeline Gelesis200 (not to be confused by Harry Potter fans with the Nimbus 2000), is based on Gelesis100 and is currently being studied for possible effects on coexisting obesity and diabetes. And as further research is conducted, we may gain the ability to predict who will be a high responder, and select those individuals for treatment.
The devil is always in the details, and we still don’t know how much these capsules are going to cost. Those of us who work to help people lose weight — and those of us who need to lose it — stand to be quite disappointed if it’s priced as high as most weight loss medications, or is not covered by insurance.
It is exciting that as we continue to understand more about obesity, we have more medical strategies to help people lose weight. I am cautiously optimistic that Plenity will represent a safe and effective option for a subset of people with overweight and obesity.