The weight-loss drug Wegovy, made by the manufacturers of Ozempic, will be available to patients in Canada starting Monday, the company says.

Novo Nordisk's weekly injection is approved for weight loss among patients diagnosed with obesity.

Wegovy can also be prescribed to patients who are significantly overweight and have at least one related medical condition such as high blood pressure, Type 2 diabetes or obstructive sleep apnea.

Health Canada approved Wegovy in November 2021, but it's taken about two and a half years to bring it to market amid supply shortages of Ozempic, which is only approved to treat Type 2 diabetes but has been prescribed off-label for weight loss.

The two drugs have the same active ingredient but Wegovy carries a higher weekly dose of semaglutide at 2.4 milligrams, compared to 1 mg in a single Ozempic dose.

Dr. Ehud Ur, an endocrinologist in Vancouver, said Wegovy allows Novo Nordisk “to segment out the two markets for obesity and diabetes.”

“But, you know, they're intimately related,” said Ur, who is not affiliated with Novo Nordisk.

“I mean, much of diabetes is caused by obesity. Many people with obesity are prone to developing diabetes. So it's a complex interaction.”

Health Canada approved Wegovy based on studies that “demonstrated a statistically significantly greater amount of weight loss in semaglutide-treated (patients) as compared to placebo-treated subjects,” according to the federal government's website.

Semaglutide mimics a hormone called glucagon-like peptide-1 (GLP-1) which promotes insulin production. It also suppresses appetite in the brain and works in the stomach so people feel fuller when they eat.

The insulin effect to treat diabetes can be achieved with a lower dose of semaglutide, but a higher dose increases the appetite suppressant effect, which is why Wegovy is a higher dose than Ozempic, Ur said.

Clinical trials showed that Wegovy was not only safe and effective for weight loss, but also had a positive impact on other weight-related conditions such as cardiovascular health, he said.

Dr. Sanjeev Sockalingam, scientific director for Obesity Canada, said obesity is a medical condition and Wegovy will be an important treatment option.

“(Wegovy) adds to the tool box and the tool kit for all clinicians who are seeing many patients living with obesity,” said Sockalingam, whose organization estimates at least eight million Canadian adults have obesity.

Obesity Canada will update its medication guidelines to include Wegovy, which is meant to be used in tandem with physical activity and nutrition, he said.

Obesity is defined as a body mass index (BMI) of 30 kilograms per square metre or greater, according to Health Canada.

In addition to patients with obesity, doctors can prescribe Wegovy to patients with a BMI of 27 kilograms per square metre and at least one weight-related medical condition. That could include hypertension, Type 2 diabetes, dyslipidemia (an imbalance of lipids such as cholesterol or triglycerides) and obstructive sleep apnea.

Wegovy arrives after extensive marketing of Ozempic and a social media-driven surge in demand for its off-label use for weight loss. Experts say it's critical that prescribers, including family doctors, ensure Wegovy is only given to patients who meet specific criteria.

“Physicians are ultimately the gatekeepers of this, and hopefully there will be responsible prescribing for the medication,” said Ur.

Sockalingam stressed that when it comes to prescribing Wegovy, “we want to make sure we're very precise, that we're not talking about ... cosmetic or physical appearance.”

“This is a medical treatment for a medical condition.”

The founder of a support group for people living with obesity called the arrival of Wegovy in Canada “a milestone moment.”

“(It is) signaling a growing recognition of obesity as a serious health issue that requires comprehensive treatment solutions,” said Priti Chawla, executive director of Obesity Matters.

But the high cost of Wegovy raises the issue of equitable access, Chawla said.

“Many in our community, and especially those in the lower socioeconomic bracket, they find these treatments are financially out of reach,” she said.

“It's essential that we work towards making Wegovy affordable and accessible to all Canadians who need it.”

Novo Nordisk Canada would not provide a specific price for Wegovy to The Canadian Press, saying in a statement that “medication pricing in Canada is influenced by multiple factors including federal, provincial and territorial governments and insurance providers, and prices may vary person to person.”

But multiple experts estimated it would likely cost around $400 a month.

Now that there is a drug specifically approved for weight loss, insurance companies “have to state specifically whether they will or will not cover this product,” said Dr. Sean Wharton, an internal medicine specialist who treats patients with Type 2 diabetes and obesity in the Toronto area.

Wharton conducts research with several drug companies developing diabetes and weight loss medications, including Novo Nordisk.

The most common side effects found in Wegovy clinical trials were gastrointestinal, including nausea, vomiting diarrhea, constipation and abdominal pain, said both Ur and Wharton.

Starting with a low dose and gradually increasing it to the 2.4 mg maintenance dose should help alleviate those symptoms, they said.

Some participants in the study also reported headache, fatigue and dizziness, Novo Nordisk's Wegovy web page said.

Semaglutide has been associated with thyroid tumours in rodents, the web page said.

There has never been a case of thyroid tumours in humans taking Ozempic or Wegovy and there is no evidence to suggest any risk to humans, Wharton said.

Ur agreed, saying someone would only be at risk if they were among the “handful” of people in Canada who already have the rare thyroid tumour.

This report by The Canadian Press was first published May 2, 2024.