Mounjaro, known as the “King Kong of slimming drugs”, will be available to patients on NHSbut this week it was announced that the drug would be prioritized for people with the highest needs – with distribution expected to last over 12 years.
We look at why the drug is in such demand and what impact it could have on the nation’s health.
What is Mounjaro?
Mounjaro is one of a growing number of weight loss injections and is manufactured by the pharmaceutical company Eli Lilly. This is a once-weekly injection that contains the drug tirzepatide and is also used to improve blood sugar in people with type 2 diabetes.
How does it differ from Wegovy?
Wegovy is also licensed for weight loss, but contains the drug semaglutide and is manufactured by the Danish company Novo Nordisk.
Both semaglutide and tirzepatide mimic a hormone produced in the body called GLP-1 – a substance that is released in the gut when we eat. This hormone slows the rate at which food empties from the stomach, acts on the brain to reduce appetite, and causes an increase in insulin production.
However, tirzepatide also mimics another hormone known as GIP (glucose-dependent insulinotropic polypeptide).
This dual action appears to be why tirzepatide is associated with greater weight loss. one A study looking at data from two clinical trials in people with type 2 diabetes spanning at least 68 weeks found that tirzepatide resulted in a weight loss of 17.8% of participants’ body weight compared to 12.4% for placebo versus placebo for semaglutide.
Who is eligible for Mounjaro?
Mounjaro is approved by the UK Medicines and Healthcare products Regulatory Agency (MHRA) for adult patients with a body mass index (BMI) of 30 or more, and those with a BMI of 27 or more who also have weight-related health problems such as high blood pressure or heart problems.
Patients can now buy the drug privately, although concerns have been raised about whether there is enough oversight sale of weight loss injections despite online pharmacies.
NHS England has also been given the green light to use the drug, although the National Institute for Health and Care Excellence (Nice) recommended to use only for people with a BMI over 35 and at least one weight-related illness, which affects around 3.4 million people in England.
However, those hoping for an NHS prescription may have to wait: on Thursday it was announced that NHS England will roll out the drug over a 12-year period. Only around 220,000 people are expected to benefit during the initial three-year period, with patients receiving care from specialist weight management services being prioritized.
The Nice guidelines for tirzepatide will also be used in Wales to support their own roll-out plans.
Why is NHS roll-out so slow?
This appears to be down to the scale of demand and concerns the NHS – and GPs in particular – may be overwhelmed.
This is due to the differences in how the different strokes are accessed. While Wegovy can only be prescribed by the NHS through specialist weight management clinics, Mounjaro can be used in all settings, including primary care or specialist weight management services, although full details have yet to be confirmed.
Prof. Jonathan Benger, chief medical officer at Nice, said: “We had to take this difficult decision to protect other vital NHS services and also to test ways of delivering this new generation of weight loss medicines.”
He also said Nice wanted to help NHS England carefully manage the introduction of tirzepatide “to ensure that other services are not disproportionately affected”.
What are the public health implications?
According to the latest Health Survey for England, 64% of adults were overweight or obese in 2022, with recent estimates suggest the situation costs the NHS £19.2 billion a year.
Benger said: “Tirzepatide and other drugs like it, such as semaglutide, will help people living with obesity lose weight and, as a result, reduce their risk of developing heart disease or stroke.”
Ministers also expressed hopes that the strikes could help people get back to workwith trials underway to investigate whether tirzepatide may have a health-economic impact.
Any concerns?
While many experts welcomed the development of effective weight loss drugs, they warned that injections such as Mounjaro and Wegovy don’t fight the root causes of obesity, stressing that politicians must do more about the environment that caused the health crisis.
They also said that for the greatest effects, such drugs should be used alongside support for nutrition, physical activity and behavior – something that could be problematic if tirzepatide was provided through primary care.
Dr Simon Cork, of Anglia Ruskin University, said GPs often do not feel qualified or able to provide this at the level required.
“The length of time it will take for tirzepatide to be introduced will be frustrating for many people who want urgent help to manage their weight, but it is understandable given the resources available in the NHS,” Cork said. “If these drugs are going to be made available to everyone who needs them, then scaling up the workforce that provides the support for these patients to maximize their effectiveness will take time and potentially a major restructuring of the way that support is currently being provided.”
