The Phase III trial for Eli Lily’s pipeline drug retatrutide for the treatment of type 2 diabetes, non-alcoholic fatty liver disease, and obesity began on 28 August 2023. This comes on the heels of the company’s successful Phase II trial, which saw retatrutide achieve a mean weight reduction of up to 17.5% at 24 weeks and 24.4% at 48 weeks in obese/overweight adults. Retatrutide suppresses appetite by binding to the GLP-1 receptors responsible for controlling hunger and satiety; this allows people to feel fuller for longer, which regulates blood sugar levels and induces weight loss.

The significant increase in the prevalence of obesity over the last few decades has resulted in the disease reaching pandemic proportions. Obesity is a severe public health problem that leads to several co-morbidities such as type 2 diabetes, cardiovascular disease, hypertension, dyslipidemia, and non-alcoholic fatty liver disease. According to the World Health Organization (WHO) worldwide, more than one billion people are obese. The World Obesity Federation’s Atlas 2023 reiterated the severity of the prevalence as they estimated that 51% of the world, which is more than four billion people, will be obese by 2035 at the current trajectory of the disease. The obesity crisis is threatening to cripple the National Health Service (NHS) in the UK. It has also racked up astronomical costs in the US as medical expenses for the obese are 30%–40% higher.

Data obtained from GlobalData’s Trials Intelligence platform shows that the number of clinical trials for obesity has increased in proportion to the prevalence of the disease (Figure 1, above). This indicates that the severity of the issue is not being taken for granted within the industry. However, the obesity crisis continues to expand regardless of the consistent clinical research that has shown the importance of prevention. This relies on the development of a long-term strategy by governments worldwide to reform approaches to nutrition, exercise, and health. Until then, treatments such as Eli Lily’s retatrutide are needed more than ever. Preliminary results indicate that retatrutide has the potential to induce weight loss more than any drug currently on the market.

GlobalData’s Likelihood of Approval tool estimates that retatrutide has a 37% chance of making it onto the market; if successful, GlobalData predicts that it could see sales of up to $349m as early as 2029. This would be a respectable contribution to the $30bn in sales GlobalData predicts that the anti-obesity drug market is expected to reach by 2029. The Phase III trial is expected to proceed until 6 February 2026, so only time will tell if retatrutide’s success is short-lived and if the pressing reform necessary to truly tackle the obesity crisis will have occurred.