A new weight loss injection will be available in the UK within weeks to treat thousands of patients with type 2 diabetes or obesity, after the medicines watchdog became the first major regulator in the world to greenlight the drug in a more convenient device. Mounjaro was developed by the US pharmaceutical company Eli Lilly. Trials show it helps those on the highest dose lose more than three stone on average. It is injected under the skin of a patient’s stomach area, thigh or upper arm, and is to be used together with a reduced-calorie diet and increased physical activity. The drug itself, also known as tirzepatide, won approval for obesity and type 2 diabetes from the Medicines and Healthcare products Regulatory Agency (MHRA) late last year but it has not yet been available due to enormous global demand. The watchdog has approved a new device for delivering the drug – a four-dose pen branded as KwikPen, covering a month’s treatment – which Eli Lilly said would enable it to supply the drug to the UK within weeks. The development, announced by the MHRA on Thursday, means there will be an alternative to the weight-loss drug Wegovy, also known as semaglutide, manufactured by the Danish company Novo Nordisk. It has been given to tens of thousands of patients on the NHS but global shortages mean it has been available only to a fraction of those eligible to take it. Julian Beach, the MHRA’s healthcare quality and access interim executive director, said: “The public health importance of safe and effective treatments to help manage diabetes and obesity, which can have a significant impact on people’s health, is clear. This approval enables access to the approved Mounjaro pen in a more convenient presentation of a month’s treatment, of one dose per week.” Eli Lilly said the green light for the more convenient device, which holds four doses instead of one, would enable the company to roll out the drug almost immediately. “The MHRA is the first major regulator in the world to issue marketing authorisation for the alternative KwikPen presentation for tirzepatide, demonstrating their clear focus on speeding innovation to help patients,” said Laura Steele, president and general manager of UK and northern Europe at Lilly. “This will enable Lilly to begin supply to the UK within weeks.” The MHRA has approved Mounjaro for patients with type 2 diabetes and patients with obesity. The drug has also been approved by the National Institute for Health and Care Excellence for use in the NHS for type 2 diabetes and is awaiting approval for obesity. Douglas Twenefour, the head of care at Diabetes UK, said: “We hope the MHRA’s approval of this device will help people living with type 2 diabetes, who are eligible, to access this effective treatment. Supporting people with type 2 diabetes to lose weight and manage their blood sugar levels is key to reducing the risk of diabetes-related complications, and tirzepatide (Mounjaro) expands the range of treatment options available to help people achieve this.” The MHRA said Mounjaro could be used to treat adults with type 2 diabetes and obese patients with a body mass index higher than 30. It will also be offered to some overweight patients with a BMI of between 27 and 30 if they also have another weight-related condition such as pre-diabetes, high blood pressure, high cholesterol or heart problems. The MHRA said the most common side-effects were nausea, diarrhoea, vomiting and constipation. Low blood sugar (hypoglycaemia) was also very common in patients with type 2 diabetes, it added.