Feb 27 (Reuters) -

Viking Therapeutics said on Tuesday its experimental drug helped patients with obesity achieve "significant" weight loss in a mid-stage study.

Novo Nordisk and Eli Lilly are so far the leaders in the weight-loss drug market, estimated to be worth $100 billion by the end of the decade, with their powerful new drugs Wegovy and Zepbound, respectively.

The following is a list of publicly listed companies targeting the next big blockbuster opportunity:

NOVO NORDISK

Novo Nordisk said a large study had shown its highly effective obesity drug, Wegovy, also had a clear cardiovascular benefit. Wegovy, which uses the same active ingredient as Novo's diabetes drug Ozempic, was approved in 2021.

The drugmaker in June reported late-stage trial data from a high-dose oral version of its drug, semaglutide, helping overweight or obese adults lose 15% of their body weight, which was in line with recent results for other experimental obesity pills.

The company on Monday said it will buy three of Catalent's fill-finish sites - in Anagni, Italy; Brussels, Belgium; and Bloomington, Indiana - from Novo Holdings for $11 billion to help boost its production of Wegovy. The sites will be acquired after Novo Holdings completes its Catalent acquisition.

ELI LILLY

Eli Lilly's weight-loss therapy, Zepbound, got the green light from U.S. and UK regulators recently, paving the way for a powerful new rival to Novo's Wegovy.

The company reported $175.8 million in sales of Zepbound in the first few weeks of its launch. The drug, chemically known as tirzepatide, has been available as Mounjaro for type 2 diabetes since 2022 and was used "off-label" for weight loss.

Lilly said a mid-stage trial of its next-generation obesity drug candidate, a once-weekly injection of retatrutide, showed it led to a weight loss of up to 24.2% after 48 weeks.

PFIZER

Pfizer said in December it was stopping further trials of a twice-daily version of its oral weight-loss drug, danuglipron.

The decision comes after most patients in a mid-stage trial dropped out with high rates of side effects such as nausea and vomiting.

The company said it will instead focus on a once-daily, modified release version of danuglipron. Data on how this version interacts with the human body is expected next year.

Pfizer had earlier scrapped the development of its once-a-day pill in June due to concerns over liver safety.

ROCHE AND CARMOT THERAPEUTICS

The company acquired CT-388 as part of its $2.7 billion buyout of Carmot Therapeutics. Carmot's once-a-week injection belongs to the same class as Eli Lilly's Mounjaro, or Zepbound.

The newly acquired drug candidate has completed early-stage trials and is ready to be tested on humans in the second of three trial stages, Roche said.

AMGEN

Amgen's experimental obesity drug, AMG133, showed a mean weight loss of 14.5% after 12 weeks of treatment at the highest monthly dose.

ALTIMMUNE

Altimmune said its drug candidate, pemvidutide, helped reduce weight by 15.6% on average and showed continued weight loss at the end of treatment in a mid-stage trial.

However, patients also experienced nausea and vomiting of mild and moderate severity.

VIKING THERAPEUTICS

Viking's mid-stage study data showed that VK2735 helped obese patients achieve "significant" weight loss.

VK2735 helped patients achieve up to 14.7% mean weight loss after 13 weeks of treatment, according to data from the study, which had enrolled 176 overweight adults with at least one weight-related comorbidity.

ZEALAND PHARMA

Denmark's Zealand Pharma and Boehringer Ingelheim's experimental obesity treatment achieved up to 14.9% weight loss in a mid-stage trial on Wednesday.

OPKO HEALTH

Opko Health has completed a mid-stage trial of its obesity drug, pegapamodutide, which it expects will have fewer side effects. (Reporting by Mariam Sunny, Pratik Jain, Sriparna Roy, Leroy Leo and Sneha S K in Bengaluru; Editing by Sriraj Kalluvila and Pooja Desai)