New medication showing promising early weight loss in trials

Tirzepatide – Once Weekly Injection for Obesity.


There has been continued interest in GLP-1 medications for weight loss in Adelaide and the rest of Australia. It is a continuously evolving landscape, and one which will be of a benefit to patients in the years to come.


GLP-1 medications, such as Saxenda and Ozempic are an important adjunct, or additive, to weight loss surgery and I have had good results using them as such. I also use GLP-1 medications in my clinic, with diet and lifestyle modification, in consultation with our experienced allied health team, to improve on patient’s weight and routines. I have also used weight loss medications, and in particular GLP-1 agonists, as pre- and post-operative agents to continue to improve on the outcomes of surgery.


Weight loss surgery outcomes, from gastric bypass or sleeve gastrectomy, are of the range of 25-30% at 1 year, and around 30-35% at 2 years. Previous trials of semaglutide (2.4mg) resulted in a placebo-adjusted weight reduction of 12.4%, with nearly one third of patients having a reduction of 20% or more. The maintenance of weight loss is important, both on and off medication, and something that will continue to be assessed in further trials.


The NEJM trial published July 21, 2022 ( is an important step forward in understanding the role of GIP and GLP-1 medications. It is part of a


Tirzepatide is a glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 receptor agonist (GLP-1).


This was a phase 3 double blinded, randomised controlled trial, for patients with a BMI of > 30 or a BMI of > 27 with a weight-related comorbidity. It is important to note that diabetics were excluded from the trial.


Tirzepatide was given at dose of either 5mg, 10mg or 15mg, or a placebo for 72 weeks. The key endpoints were % change in weight, and a weight reduction of 5% or more.


The results of the study were significant, with more weight loss than previous medications. The mean percentage change in weight at 72 weeks was -15.0% with 5mg, -19.5% with 10mg, and -20.9% with 15mg. The placebo provided -3.1% weight loss.


In regards to the number of patients who achieved a weight loss of 5% or more, this was: 85% for 5mg, 89% for 10mg and 91% for 15mg. It is interesting to note that 35% of the placebo group lost 5% or more.


Further to this, 35% of the 5mg group, 50% of the 10mg group and 57% of the 15mg lost 20% or more of their body weight, with 3% of the placebo group losing 20% or more of their body weight during this time. In regards to adverse events, this was low, at 4.3% for 5mg, 7.1% for 10mg and 6.2% for 15mg. 2.6% of the placebo group discontinued treatment also.


The 72-week phase 3 trial demonstrated significant weight loss. This is promising data, however further trials are necessary to assess outcomes over a longer period, as well as after cessation of medication.


It is important to note that there are more options becoming available for patients with obesity, and as a bariatric or weight loss surgeon practicing in Adelaide, I continue to provide all options for my patients. Therefore, I provide surgery, as well as medical treatments and non-operative treatments including the Allurion Balloon. Well-rounded care, with options for patients is important and means better outcomes for patients long-term.  The addition of GIP/GLP-1 agonists to weight loss surgery such as sleeve gastrectomy and gastric bypass, may mean our team are able to achieve improved total body weight loss of over 40% or excess weight loss of above 80%. This could bring even further improvement to co-morbidities for patients with obesity.


It is always important to consult with a doctor. Please contact our rooms if you would like to book a consultation with me or a member of our clinical team to discuss your individual situation.

Thank you, Dr George Balalis.


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