Lilly stays ahead of the pack as rivals jump on obesity drug bandwagon

NEW YORK/LONDON - Eli Lilly has solidified its leading position in the booming market for obesity drugs ahead of a wave of possible new entrants to the space.

Lilly last weekend presented more detailed data from trials of its once-weekly injection retatrutide, confirming to investors and clinicians that its experimental drug is likely to offer the greatest weight loss prospects of any medicines currently on the market or in the pipeline.

Roche, AstraZeneca, Pfizer and others also presented fresh data that turned the American Diabetes Association meeting in New Orleans into more of a weight-loss conference, and raised the prospect of greater choice in a fast-growing market so far dominated by Indianapolis-based Lilly and Denmark's Novo Nordisk.

Drugs presented by Novo, Roche and others are "on par" with current ones in terms of weight loss and side effects but cannot compete with Lilly's next-generation products, said RBC analyst Trung Huynh.

"The bar is just moving higher and higher," he said in a phone interview.

Eli Lilly shares closed 1.6% higher on Monday, the first trading day following the ADA conference. Shares of Novo fell 4.2% and Roche, Pfizer and Zealand Pharma, which is developing obesity injection petrelintide with Roche, all lost ground.

DOMINATING MARKET SEGMENTS

With prices falling and a growing number of weight-loss options on the horizon, some companies may set their sights on certain segments of the patient population.

Roche says patients seeking maximum weight loss may choose more potent therapies such as its experimental dual-acting enicepatide, while others may choose a trade off of more modest weight loss and fewer side effects that could be easier to stay on longer term.

"We have to look at the entire gamut of people living with obesity because it's so heterogeneous, it's complex, and there is going to be segmentation," said Manu Chakravarthy, who oversees cardiovascular, renal and metabolism product development at Roche.

In data presented at ADA, Roche said patients lost 22.7% of their bodyweight in a mid-stage trial of enicepatide with a gastrointestinal side effect profile similar to existing GLP-1s.

Chakravarthy said once-weekly injection petrelintide, an amylin-based drug, has a "placebo-like" tolerability profile that could give it an edge.

AstraZeneca said it sees its oral GLP-1 elecoglipron as the foundation of a broader obesity strategy that could include combinations with its medicines for type 2 diabetes and kidney and heart disease.

For both Novo and Lilly, the strategy remains to cover the waterfront with multiple options for a large, diverse market.

"Rather than taking a one-size-fits-all approach, we aim to match the right medicine to the right patient," said Novo Chief Medical Officer Filip Knop.

Lilly also says it expects to provide the broadest set of options for people living with overweight and obesity. Kenneth Custer, president of Lilly Cardiometabolic Health, said patients "may even choose to start on one Lilly medicine and move to another Lilly medicine."

FEWER SIDE EFFECTS HARD TO COME BY

While companies push weight-loss boundaries, the area with the greatest room for improvement is the daunting side effect profile of some of these medicines. The therapies that rely on the GLP-1 and GIP hormones tend to cause stomach issues such as nausea and vomiting.

Discontinuation rates in clinical trials due to side effects has become a closely watched data point by Wall Street. Studies put the percentage of patients who experience nausea at about 40% for some drugs.

Pfizer said its experimental drug berobenatide has a similar side effect profile to Novo's Wegovy. The drug could become the first GLP-1 to be offered as a monthly shot.

"Tolerability really is the unmet medical need at the moment," said HSBC analyst Rajesh Kumar.

"As long as you're getting over 12%, 15% weight loss, most people don't need more than 20%. You want something that is competitive on efficacy, good tolerability, and people can take on a regular basis."

Therapies that don't prompt GI side effects are likely a ways off. Lilly, Pfizer, AbbVie, Astrazeneca and Roche with Zealand are all working on amylin-based drugs.

Novo's Cagrisema, which combines semaglutide with an amylin drug and was seen as a potential Wegovy successor, fell short on weight-loss expectations.

Lilly's experimental eloralintide also aims to fill that improved tolerability need.

"What we've seen with the amylin class so far is that it seems to really stand out" on tolerability, Custer said. "We want to make sure for the 5% to 10% of patients who would like something else, that we have an option to give them."

(Reporting by Chris Prentice and Michael Erman in New York and Maggie Fick and Bhanvi Satija in London; Editing by Caroline Humer and Bill Berkrot)

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This story was originally published June 10, 2026 at 9:33 AM.