Weight loss drug Wegovy has transformed the obesity market and pharmaceutical companies with existing treatments are hoping the resulting demand will boost demand for their older, less effective but cheaper, drugs.

A weekly injection of Wegovy, which was launched in the US in June 2021, leads to an average weight loss of around 15%, alongside changes to diet and exercise. Its impact has captured the attention of patients, investors and even celebrities.

But supply issues for Wegovy manufacturer Novo Nordisk (NOVOb.CO) means the Danish drugmaker has struggled to meet surging US demand, delaying a launch in most of Europe.

Insurers and some national governments have also baulked at its cost, while a minority of patients do not respond to it.

Vivus and Currax Pharmaceuticals, US-based developers whose treatments have been on the US market for around a decade, hope to benefit from the attention and supply shortage.

But scientists and investors say that lower efficacy plus side effects could continue to hold the treatments back.

In the coming months, Vivus plans to launch its pill, sold as Qsiva in Europe and Qysmia in the US, in Sweden, Norway, Denmark, Finland and Iceland. It already has regulatory approval in the US, Poland and South Korea, as well as these countries.

Vivus has also submitted evidence to the British regulator for the pill, and is in talks with regulators in a number of other European countries as well as in the Middle East and Mexico, its chief executive John Amos told Reuters during the European Congress on Obesity last week in Dublin.

“The new agents have created a much broader (awareness): obesity is not a series of bad choices, it’s a medical condition that requires therapy,” he said.

Qsiva was rejected by the European Medicines Agency in 2013 over safety fears, which Amos said were “overblown”, as US patients have been using it for years without major red flags. Vivus said annual sales now total more than $150 million.

The drug, which is not recommended for people with unstable heart disease and can cause mood disorders and eye problems, leads to around 11% weight loss, and works in a different way to the new class of drugs.

Demand

The obesity market is predicted to ultimately support 10 manufacturers, with annual sales of $100 billion in 10 years, industry executives and analysts say.

The demand surge after Wegovy’s launch has already boosted Novo’s older GLP-1 drug, Saxenda, which has a different active ingredient and lower effectiveness, reducing weight by between 5% and 10% on average. Sales jumped 42% to 10.6 billion Danish crowns ($1.5 billion) last year compared to 2021.

Others are also lining up, with Eli Lilly (LLY.N) likely to be the next to launch its drug, a GLP-1 agonist like Wegovy, later this year, followed by Pfizer (PFE.N) and others.

Currax said its drug, marketed as Contrave in the US and Mysimba in Europe, is already approved in 40 countries, with annual sales of around $100 million. It reduces weight by around 5% on average.

“There are enough patients suffering from obesity, sadly, that can benefit from a drug,” said Currax Chief Medical Officer Michael Kyle. “We want patients and healthcare providers to have other choices.”

Both said there had been interest from researchers and physicians in combining their drugs with the new GLP-1 agonists, although no trials have yet been listed on official databases.

Obesity experts said there was a role for the older drugs despite their issues, not least because they cost hundreds, rather than thousands, of dollars monthly.

“Once the world views obesity as a disease, healthcare providers will look for other things that can benefit their patients,” said Lee Kaplan, director of the Obesity and Metabolism Institute in Boston, United States, who has consulted for other obesity drug manufacturers.

But investors said the issues with the older drugs, notably efficacy and tolerability, could continue to hold them back.

“I can imagine people trying options but then I wouldn’t expect those to see a sustained resurgence,” said Andrew Levin, managing director of US-based healthcare and life sciences investment group RA Capital Management.