An experimental weekly weight-loss injection could emerge as a rival to popular treatments including Wegovy and Mounjaro, according to new research.
In a clinical trial, ribupatide helped participants lose an average of 17.7 per cent of their body weight—nearly one-fifth—in 11 months.
Among patients given the highest dose, half lost more than 20 per cent of their starting weight.
Those receiving the two largest doses were also continuing to lose weight when the 48-week study ended, suggesting the full effect of the treatment may not yet have been seen.
Wegovy, which contains semaglutide, has been shown to produce an average weight loss of about 18.7 per cent after 72 weeks—roughly 16 and a half months.
Mounjaro, made with the active ingredient tirzepatide, has delivered weight loss of approximately 22.5 per cent over the same period.
Although the medicines have not been tested directly against one another, the results indicate that ribupatide could become a significant competitor in the rapidly expanding weight-loss drug market.
The findings were published only months after recruitment began for phase three trials of ribupatide in the UK.
An experimental weekly weight-loss injection could challenge blockbuster drugs such as Wegovy and Mounjaro, research suggests
Ribupatide works in a similar way to Mounjaro by imitating the effects of two hormones involved in appetite and blood-sugar regulation.
As a result, users may feel fuller for longer, helping to curb hunger and reduce the amount they eat.
For the study, published in JAMA, researchers from Fudan University in Shanghai recruited 567 overweight or obese adults whose average age was 34.
A total of 424 participants were randomly allocated to weekly ribupatide injections of 2mg, 4mg or 6mg. The remaining 143 received a placebo.
After 48 weeks, people taking the 2mg dose had lost an average of 10.7 per cent of their body weight.
Average weight loss reached 16.4 per cent among those on 4mg and 17.7 per cent among participants given 6mg.
The placebo group, by comparison, lost an average of just 1.4 per cent.
A number of participants achieved substantially greater reductions.
At least one-fifth of their starting weight was lost by 13.6 per cent of the 142 people taking 2mg, 37.1 per cent of the 141 receiving 4mg and 44.4 per cent of the 141 given 6mg.
The researchers said the drug may not have reached its maximum effect by the end of the trial.
‘Reductions in body weight at week 48 were 16.4 per cent and 17.7 per cent with ribupatide 4mg and 6mg, respectively, and weight loss had not clearly plateaued in either group,’ they wrote.
Weight loss from these medicines often slows as treatment continues because a smaller body requires fewer calories to function.
As with other weight-loss injections, which are used by around 2.5 million people in Britain, the most frequently reported side effects involved the stomach and digestive system.
Nausea, vomiting and diarrhoea affected about half of those on the lowest dose and roughly two-thirds of participants taking the highest dose.
Most of these side effects were described as mild or moderate.
The injection was also linked to improvements beyond weight reduction, including better blood pressure, blood-sugar control and cholesterol readings.
Around 14 million adults in the UK have high blood pressure, a condition that can raise the risk of potentially fatal illnesses such as heart failure.
Maintaining healthy blood-sugar levels can help protect against type 2 diabetes, while lowering cholesterol may reduce the risk of stroke.
Systolic blood pressure—the upper figure in a blood-pressure reading—fell by around seven to nine points more among ribupatide users than in the placebo group.
Triglycerides, blood fats that can contribute to serious health problems when levels are too high, fell by approximately 29 to 37 per cent more than with placebo.
Ribupatide also appeared to improve the body’s sensitivity to insulin, the hormone responsible for helping regulate blood sugar.
Insulin resistance declined by 30 per cent among those taking 2mg, by 44 per cent in the 4mg group and by 46 per cent among participants on 6mg.
Total cholesterol fell by 6 per cent with the 2mg dose, 9 per cent with 4mg and 8 per cent with 6mg.
Waist circumference also decreased, a potentially important measure because it can reflect visceral fat stored deep in the abdomen around vital organs.
Participants taking ribupatide lost an average of around 9cm to 14cm from their waistlines, compared with approximately 2.5cm in the placebo group.
Despite the positive results, the researchers acknowledged several limitations to the study.
‘First, the 48-week treatment period may not have captured the full weight loss effect of ribupatide 4mg and 6mg,’ they wrote.
‘Second, participants were relatively young, and the efficacy and safety findings may not be generalisable to older adults with overweight or obesity.’
The results come three months after clinical trials began recruiting participants in cities including Manchester, London and Nottingham.
In those trials, researchers plan to compare weekly ribupatide doses of up to 10mg with placebo over 18 months in people both with and without diabetes.
A separate study involving around 1,200 participants in the UK and several other countries is also comparing ribupatide directly with semaglutide.