Tirzepatide (Mounjaro) finally available in Canada
Good news - Mounjaro, which was approved by Health Canada in November, 2022 is finally available in Canada! This is a medication that is approved for use in diabetes after excellent results in the SURPASS trials. It acts on two different hormones - glucagon like peptide 1 (GLP1) and gastric inhibitory peptide (GIP) which cause more insulin to be released in the body and decrease hunger and gut mobility.
In the SURPASS diabetes studies, Mounjaro was shown to reduce HbA1C (3 month glucose average) by 2.1-2.6% which is greater than any other single agent has been able to do. It also and led to an average weight loss of 9.5-12.5% among patients living with diabetes. This is especially impressive.
Initially, Mounjaro was approved to be given in a simple-to-use self-injecting device but given supply constraints, it is now going to be available in a vial instead. This means patients will have to draw it up with a needle and syringe and self-administer it once a week. Like current GLP1 agents available today, the dose should be titrated up slowly to minimize side effects which are mostly gastrointestinal - nausea, heartburn, constipation and more infrequently vomiting and diarrhea.
In the SURMOUNT-1 trial, Mounjaro has been found to be effective in the treatment of excess weight in patients with a body mass index (BMI) of 27 or higher along with one obesity related comorbidity along with patients living with obesity (BMI of 30 or higher). At 72 weeks, the average change in weight ranged from 15% on 5 mg doses to 20.9% on 15 mg doses.
Other GLP1 agents such as liraglutide and semaglutide were also only for diabetes initially and were later approved for weight loss. This is what will likely happen with Mounjaro in 2024. Currently it is only approved for use in diabetes in both the US and Canada. Healthcare providers trained in obesity medicine and eager to help patients avoid the secondary complications of obesity have started using it off label for weight loss.
Learn more technical background about GIP and GLP here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4020673/
Learn more about the GLP/GIP combination here: https://www.mdpi.com/2075-1729/12/1/29
Learn more nitty gritty about the SURASS1 trial in the Lancet here: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)01324-6/fulltext
Learn about the SURMOUNT1 study in the New England Journal of Medicine here: https://www.nejm.org/doi/full/10.1056/NEJMoa2206038
Learn more at the official Mounjaro website in Canada: https://www.lillyproducts.ca/en/mounjaro