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Semaglutide shortage sparks patient demands for alternatives
But in Australia, the new drug generating the most interest is still in its infancy – and not yet listed on the PBS.
GPs are increasingly receiving requests for new GLP-1 receptor agonist prescriptions to manage diabetes and obesity.
A critical shortage of semaglutide (sold as Ozempic) coupled with growing demand for weight loss medication has resulted in many GPs receiving requests for other treatment options.
As it stands, Australia has four GLP-1 receptor agonists registered with the Therapeutic Goods Administration (TGA):
- Dulaglutide (sold as Trulicity)
- Semaglutide (sold as Ozempic)
- Liraglutide (sold as Saxenda)
- Tiezepatide (sold as Mounjaro)
However, each of these options has varying limitations. Dulaglutide and semaglutide are the only two listed on the PBS for treatment of type 2 diabetes, but neither are approved for weight loss. Meanwhile, liraglutide is approved for both, but is not subsidised at all.
The newest alternative is tirzepatide, which is different to other glucagon-like petide-1 (GLP-1) receptor agonists.
The novel agent targets both GLP-1 and glucose-dependent insulinotropic polypeptide (GIP) receptors a dual action that has been shown to achieve significant reductions in HbA1c and as a secondary effect, considerable weight loss.
It was launched shortly after semaglutide became largely unavailable, and began to generate interest in Australia after separate pharmaceutical-sponsored trials, published in the
New England Journal of Medicine.
These trials indicate the drug can not only reduce HbA1c levels in
patients with diabetes by 2.3 points over 40 weeks at a dose of 15 mg per week, and reduce baseline body weight by over 20% after 72 weeks in
patients with obesity (but not diabetes).
The results and subsequent listing also prompted a flurry of mainstream media reports, with outlets such as 7NEWS
describing it as ‘King Kong’ in comparison to its ‘rival’ semaglutide.
But like its forebears, the Eli Lilly-manufactured medication comes with prescribing limitations – most notably that it is not PBS-listed, nor approved in Australia for weight loss – and side effects.
So what do GPs need to know?
A little over seven months after the TGA
approved tirzepatide for the management of type 2 diabetes as part of combination therapy (or as a monotherapy if metformin is not tolerated), the
Pharmaceutical Benefits Advisory Committee (PBAC) rejected a submission from Eli Lilly to list tirzepatide on the PBS.
The committee explained its decision by noting that while the drug is superior to PBS-listed semaglutide at higher doses in achieving glycaemic control and weight loss, it is not superior at lower doses.
The PBAC also cited a high price point as a reason for rejecting the PBS listing application, saying a ‘significant price reduction’ would be needed for the proposal to be cost-effective.
Notably, it is not yet approved for weight loss management anywhere in the world, while
ongoing research has also confirmed tirzepatide poses similar side effects to those associated with other GLP-1 receptor agonists, such as gastrointestinal problems and muscle-mass loss.
Despite this, tirzepatide is now available on a private prescription in single-use vials, rather than pre-filled pens, to expedite supply. It can be prescribed at multiple doses, ranging from 2.5 mg – 15 mg, and
patients need training on how to draw up and administer the medication using a needle and syringe.
Unlike the
strict guidelines in place for doctors prescribing semaglutide, with off-label prescribing strongly discouraged due to demand outstripping supply, the regulator has not released specific guidance on prescribing tirzepatide and a TGA spokesperson told
newsGP there are no immediate plans to do so.
‘Every medicine shortage situation is unique … and there have been no reports of anticipated supply disruptions for Mounjaro at this time. As such, there are no current plans to publish specific advice relating to this product,’ the spokesperson said.
‘Prescribing a medicine for an indication that has not been approved by the TGA is not illegal. It is not the role of the TGA to regulate the clinical decisions of health professionals, and we are unable to prevent doctors from using their clinical judgement to prescribe medicines for other health conditions.
‘However, with the recent shortage of Ozempic [semaglutide], in addition to other shortage management actions, we have strongly recommended that health professionals refrain from off-label prescribing and prioritise patients with type 2 diabetes who need it most.’
Earlier this year, the CEO of NovoNordisk, which manufactures semaglutide,
told Reuters that it will take ‘years’ for the company to be able to fully meet demand. However, reports of growing
tirzepatide shortages are also now emerging from the US,
particularly within higher doses.
Dr Gary Deed, Chair of RACGP Specific Interests Diabetes, recommends that tirzepatide still be reserved for those with type 2 diabetes and that side effects and risks are both considered when prescribing the medication.
‘It may lead to weight loss; however, in Australia it should be limited to people with type 2 diabetes who can afford it and need it on an individual basis – some of which may need weight management,’ he told
newsGP.
‘Whether it will be used just for weight management requires careful prescribing.
‘All of these injectables may have significant risks of gastrointestinal side-effects including vomiting and carry risks if female patients fall pregnant.’
What other options are on the horizon?
Clinical trials for new GLP-1 receptor agonists and other agents that are effective at optimised glycaemic control in diabetes and lead to weight loss are in various phases. Eli Lilly is currently undertaking trials for two GLP-1 receptor agonists, retatrutide and an oral alternative called orforglipron, neither of which are approved for therapeutic use at this stage.
Another oral GLP-1 receptor agonist is also in the Pfizer’s
research pipeline. The drug, danuglipron – still considered and ‘experimental medicine’, entered phase 2 trials earlier this year, with 1400 participants enrolled in trials for the treatment of type 2 diabetes and obesity.
The company recently discontinued trials for another oral GLP-1 receptor agonist known as lotiglipron due to concerns related to its effects on liver function.
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diabetes dulaglutide liraglutide obesity semaglutide tirzepatide weight loss
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