June 27 (Reuters) -

Drug developers are chasing an obesity drug gold rush that may be worth up to $100 billion by rolling out treatments that can help lose as much as 24% of weight in less than a year.

The success of these treatments, especially from companies such as Novo Nordisk and Eli Lilly, has attracted the attention of celebrities, including Tesla CEO Elon Musk and former UK Prime Minister Boris Johnson.

The new class of drugs, which trigger a feeling of fullness after eating, has also given hope to millions of people who are overweight and are looking to shed those extra pounds without much effort.

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

NOVO NORDISK

Novo Nordisk said on Sunday a high-dose oral version of its drug, semaglutide, helped overweight or obese adults lose 15% of their body weight in a late-stage trial, which was in line with recent results for other experimental obesity pills.

Novo, which plans to seek U.S. and European regulatory approvals for the high-dose pill later this year, said the timing of a market launch is yet "to be determined".

Novo Nordisk's weekly injection Wegovy, known as Ozempic when used for diabetes, was approved in 2021.

The company also has an older product Saxenda, approved in 2014, but Wegovy is considered safer and more effective.

ELI LILLY

Eli Lilly said on Monday 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.

The drugmaker on Friday

said

the highest dose of its experimental pill, orforglipron, helped people who were obese or overweight lose 14.7% of their body weight after 36 weeks in a mid-stage trial.

Lilly reported

last year

that its other drug, Mounjaro, showed a 22.5% weight loss in people who were obese or overweight but did not have diabetes. In people with obesity who also have diabetes, the drug led to an average of 15% bodyweight loss, data showed on Friday.

Mounjaro, also known as tirzepatide, is awaiting U.S. regulatory approval for the treatment of obesity. It targets Glucagon-like peptide-1 (GLP-1), a hormone that helps decrease blood sugar levels, as well as a second obesity-related hormone called GIP.

PFIZER

Pfizer Inc said on Monday it was scrapping the development of its once-a-day pill on concerns about liver safety, but will continue developing its other obesity pill, the twice-daily danuglipron.

The company expects to finalize plans for a late-stage program for danuglipron by the year-end and is also developing a once-daily version of that drug.

In May, danuglipron

showed

results in weight loss similar to that of Novo's semaglutide.

AMGEN

Amgen Inc's experimental obesity drug, AMG133, showed promising durability trends in an early-stage trial late last year. The drug candidate showed a mean weight loss of 14.5% after 12 weeks of treatment at the highest monthly dose.

ALTIMMUNE

Altimmune Inc said in March its drug, pemvidutide, helped reduce weight by more than 10% on average in a mid-stage trial.

However, the drug candidate also showed safety concerns with patients experiencing nausea and vomiting of mild and moderate severity.

VIKING THERAPEUTICS

Viking Therapeutics Inc's drug, VK2735, showed up to 6% reduction in mean weight in an early-stage study.

The company plans to test higher doses of the drug over a longer treatment window in a mid-stage trial.

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 and Sriparna Roy in Bengaluru; Editing by Sriraj Kalluvila and Anil D'Silva)