Enlarge / Packaging for Wegovy, manufactured by Novo Nordisk, is seen in this illustration photo. (credit: Getty | Jakub Porzycki)

With the debut of remarkably effective weight-loss drugs, America's high obesity rate and its uniquely astronomical prescription drug pricing appear to be set on a catastrophic collision course—one that threatens to "bankrupt our entire health care system," according to a new Senate report that modeled the economic impact of the drugs in different uptake scenarios.

If just half of the adults in the US with obesity start taking a new weight-loss drug, such as Wegovy, the collective cost would total an estimated $411 billion per year, the analysis found. That's more than the $406 billion Americans spent in 2022 on all prescription drugs combined.

While the bulk of the spending on weight-loss drugs will occur in the commercial market—which could easily lead to spikes in health insurance premiums—taxpayer-funded Medicare and Medicaid programs will also see an extraordinary financial burden. In the scenario that half of adults with obesity go on the drug, the cost to those federal programs would total $166 billion per year, rivaling the programs' total 2022 drug costs of $175 billion.

Enlarge / Wegovy is an injectable prescription weight-loss medicine that has helped people with obesity. (credit: Getty | Michael Siluk)

A large, long-term trial of the weight-loss medication Wegovy (semaglutide) found that people tended to lose weight over the first 65 weeks on the drug—about one year and three months—but then hit a plateau or "set point." But that early weight loss was generally maintained for up to four years while people continued taking the weekly injections.

The findings, published Monday in Nature Medicine, come from a fresh analysis of data from the SELECT trial, which was designed to look at the drug's effects on cardiovascular health. The trial—a multicenter, double-blind, randomized, placebo-controlled trial—specifically enrolled people with existing cardiovascular disease who also were overweight or obese but did not have diabetes. In all, the trial included 17,604 people from 41 countries. Seventy-two percent of them were male, 84 percent were white, and the average age was about 62 years old.

Last year, researchers published the trial's primary results, which showed that semaglutide reduced participants' risk of heart attack, stroke, and cardiovascular-related deaths by 20 percent over the span of a little over three years.