A "game-changing" immunotherapy drug proven to delay the development of type 1 diabetes has been approved by regulators in the USA.

Experts say teplizumab marks a "new era" in treatment, tackling the root cause of the condition for the first time, rather than just the symptoms.

It works by reprogramming the immune system to stop it mistakenly attacking pancreatic cells which produce insulin.

In 2019, a trial showed the drug delayed some people at high risk of the condition from developing it for an average of three years.

Experts say this delay can be very significant, particularly for young people who would not have to take daily insulin or monitor their sugars as intensively for that period of time.

They suggest people could also spend more years with their blood sugars in a healthy range, offering more time to be protected from the complications of high blood sugars such as kidney or eye disease.

edit added: The monoclonal antibody teplizumab, which will be marketed under the brand name Tzield, from ProventionBio and Sanofi is given through intravenous infusion. The drug is approved for people who don’t have any symptoms of the disease and may not know they’re on the road to getting it.