Orforglipron could make weight-loss drugs more affordable

Weight-loss injections including Wegovy and Mounjaro have changed the treatment of obesity. In the past year, roughly 1.6 million adults in Great Britain have taken weight-loss drugs, and most have paid for these medicines through private providers.

Yet these treatments have a drawback: although they can be highly effective at reducing weight during use, research shows that people often regain a substantial amount of weight after stopping them.

The associated health gains can fade too. Improvements in blood pressure, blood glucose and lipid levels observed while taking these medicines also tend to be lost.

A private Mounjaro prescription in the UK costs around £300 per month, which is the central problem. For most patients, paying this amount indefinitely is not viable.

Why weight-loss injections cost so much

Their high price largely reflects how they are produced.

The drugs' active ingredients are peptides: small proteins that are quickly broken down by the stomach and digestive system, so they have to be delivered by injection. The injection pens are also costly to manufacture and require refrigerated storage.

Orforglipron, marketed as Foundayo, is a once-daily oral weight-loss medicine that acts on the same GLP-1 system as Wegovy. It has recently received approval from the US Food and Drug Administration for obesity treatment.

Its active ingredient is not a peptide but a "small molecule". This enables it to survive the digestive system's harsh conditions, while making it considerably cheaper to manufacture and store. Most medicines, including aspirin, ibuprofen and statins, are small-molecule drugs.

This could make orforglipron an important addition to the weight-loss market, potentially widening access to these significant medicines.

In the US, a one-month supply of orforglipron costs between US$149 and US$299 (£112-£224). A monthly supply of Mounjaro, by comparison, costs more than US$1,000.

Clinical trials indicate that orforglipron produces body-weight loss of a little over 15% in adults with obesity. That is comparable with the results achieved with Wegovy, though notably below the 21% weight loss reported with Mounjaro.

More importantly, orforglipron may offer a way to address the major challenge facing weight-loss drugs: the swift return of weight after treatment ends.

Keeping the weight off with orforglipron

Researchers have recently released results from a trial examining whether weight lost with Wegovy or Mounjaro could be maintained after patients switched to orforglipron.

The trial enrolled patients who had lost at least 5% of their body weight over 72 weeks while using one of the two established weight-loss injections. They stopped their original medicine and then received either orforglipron or a placebo for 52 weeks.

Of the patients who had initially used Mounjaro, those given the placebo had regained just over 50% of the weight they had lost by week 52.

By contrast, participants taking orforglipron regained only 26%. More than two-fifths of them retained over 80% of their body-weight reduction.

Comparable findings emerged among patients who had originally used Wegovy. Those receiving a placebo tablet regained 62% of their lost body weight, while the orforglipron group regained 21%.

Health markers after switching treatment

In both groups, people taking orforglipron also maintained improvements in important health measures, including blood sugar, blood pressure, insulin and cholesterol levels.

The study was small, involving only just over 100 people in each group. Nevertheless, it points to a promising possibility: weight loss from these medicines, as well as their broader health benefits, may be sustained over the long term in a potentially more affordable way.

Orforglipron is not currently licensed for weight loss in the UK. If it receives approval from the UK's Medicines and Healthcare products Regulatory Agency, it is expected to become available between late 2026 and early 2027.

Simon Cork, Senior Lecturer in Physiology, Anglia Ruskin University

This article is republished from The Conversation under a Creative Commons licence. Read the original article.