This class of medication to treat T2DM has shown weight-loss benefits comparable to bariatric surgery, say experts.
A new self-injectable drug to treat adults with type 2 diabetes has been launched today at the 2023 Australasian Diabetes Congress.
Touted as the first new class of T2D medicines to be introduced in almost a decade, tirzepatide (Mounjaro, Eli Lilly) was approved by the TGA earlier this year. The company’s application to have it PBS-listed was considered by PBAC in July but was unsuccessful.
However, Eli Lilly announced today it would be making the drug – which has impressive weight loss benefits and reductions in HBA1c – available as a private script while it considers its PBS options. The company is finalising the actual date for product availability in Australia, but it is expected to be late September.
“Lilly has decided to launch Mounjaro as a private prescription so that our Australian patients with type 2 diabetes can have immediate access to the HbA1c and weight reductions that Mounjaro may offer,” a spokesperson told TMR.
“As a private prescription, the final price will be determined by the pharmacy. Lilly will be providing a recommended retail price for Mounjaro prior to product availability in September.”
Ahead of the congress launch, Dr Kevin Lim, associate vice president of medical at Eli Lilly Australia, told TMR that Australia was the sixth country to receive tirzepatide.
“We’ve been very careful about launching only when we know that we’re going to be providing enough supply,” he said.
The arrival of the drug is expected to create a stir in the market, judging by the massive demand for other T2D GLP-1 self-injectables like semaglutide and dulaglutide that have been used off-label in Australia for a number of years.
That demand, which has been seen around the world, has created crippling shortages of both drugs, although these are reportedly easing. Dr Lim said he was confident the company could meet supply demands for tirzepatide.
Unlike the GLP-1 (glucagon-like peptide-1) receptor agonists semaglutide and dulaglutide, tirzepatide includes a GIP (glucose-dependent insulinotropic polypeptide) receptor agonist.
It is registered and indicated for the treatment of adults with insufficiently controlled type 2 diabetes mellitus as an adjunct to diet and exercise; and as monotherapy when metformin is not tolerated or contraindicated or in addition to other medicinal products for the treatment of type 2 diabetes.
Associate Professor Sof Andrikopoulos, CEO of the Australian Diabetes Society, told The Medical Republic the new drug was a gamechanger.
“It’s a really big change in the management of type two diabetes,” he said.
“It’s almost revolutionary, because the weight loss, and then the subsequent reduction in HbA1c is better than what we’ve seen with any other drug.
“If you look at the data, you’re getting up to 15% weight loss, and you’re getting to 2.2% reduction in HbA1c – so you’re getting people into the remission range.”
While tirzepatide was not registered for use as a specific weight-loss drug – and Dr Lim told TMR the company would not advocate for its use outside indications – Professor Andrikopoulos said provided there were no supply issues, he could not see why it shouldn’t be made available.
“Given its 15% weight loss, which is approaching bariatric surgery levels, why shouldn’t people with obesity – who are at increased risk of type two diabetes, cardiovascular disease, certain forms of cancer, sleep apnoea, and all those associated comorbidities – get access to a drug that will reduce their weight, maintain their reduced weight, but also, more importantly, prevent or delay onset of complications?” he said.
Professor Andrikopoulos said the benefits for lowering HbA1c levels should also not be underestimated.
“The impact on HbA1c is remarkable … you’re getting people into remission territory which is only at the moment possible with bariatric surgery,” he told TMR.
The registration of tirzepatide follows the publication of five global randomised, controlled, phase III studies (SURPASS 1-5) to assess glycaemic efficacy as the primary objective. This included one study published in the New England Journal of Medicine.
The studies evaluated three different doses of tirzepatide (5mg, 10mg and 15mg) either as monotherapy or as an add-on to other diabetes medications.
Based on the SURPASS clinical study outcomes, treatment with tirzepatide demonstrated sustained, significant and clinically meaningful reductions from baseline in HbA1c and body weight compared to placebo or active control treatments for up to one year. HbA1c reductions of 2.1-2.5% were seen across the three doses, and weight reduction of 7.8-12.4 kg across all three doses.
Tirzepatide was well tolerated across the studies, with a low risk of hypoglycaemia when used without insulin or insulin secretagogues, and it showed a generally similar safety profile to the GLP-1 receptor agonist class.
The most frequently reported adverse reactions in clinical studies were gastrointestinal disorders, including diarrhoea and vomiting. In general, these reactions were mostly mild or moderate in severity and occurred more often during dose escalation and decreased over time.
According to the product information, tirzepatide will be available in six doses (2.5mg, 5mg, 7.5mg, 10mg, 12.5mg, 15mg). The TGA approval does come with a Black Triangle Scheme warning, which will mean tirzepatide will be subject to additional monitoring in Australia.
The drug is not for use in people with type 1 diabetes, and it is not known if it is safe and effective for use in patients under 18 years, or in people who have had inflammation of the pancreatitis.
Eli Lilly Australia general manager Tori Brown said the company was currently reviewing the details of PBAC’s decision not to allow PBS listing for Mounjaro “to determine the best pathway forward”.
“Lilly has decided to launch Mounjaro as a private prescription so that Australian patients with type 2 diabetes can have immediate access to the HbA1c and weight reductions that Mounjaro may offer,” she said.
“We are committed to making this first-in-class medicine1 accessible for adult patients living with type 2 diabetes and our ultimate goal is to secure reimbursement on the Pharmaceutical Benefits Scheme (PBS).”