May 20 (Reuters) - Certain genes may identify patients with obesity who are most likely to respond strongly to Novo Nordisk's weight-loss drug Wegovy, researchers reported on Monday.

The study, released at the Digestive Disease Week meeting in Washington, found a 95% likelihood that patients with this genetic profile would be strong responders to the treatment.

Given the expense of Wegovy, the findings might be used to identify the patients most likely to get the greatest benefit from it, according to Dr. Andres Acosta of the Mayo Clinic in Rochester, Minnesota, one of the researchers.

Some people with obesity have a genetic profile that contributes to what is called a "hungry gut" - that is, they feel full during a meal but become hungry again shortly afterward because food leaves their stomach more quickly than in most other people, Acosta said.

The study involved 84 patients prescribed Wegovy for treatment of obesity. Those with the genetic variants associated with "hungry gut" lost an average of 14.4% of their total body weight after nine months on the drug and 19.5% after a year, the study found.

By comparison, study participants without this genetic profile lost 10.3% of their body weight after nine months and nothing more by 12 months.

Acosta said the researchers previously saw a similar pattern in patients taking the weight-loss drug liraglutide, which is marketed under the names Victoza and Saxenda by Novo Nordisk.

While patients without the "hungry gut" genes did lose some weight on Wegovy, they might be able to lose similar amounts with less-expensive therapies, Acosta said. The list price for Wegovy, also called semaglutide, is $1,349.02 per month.

"When you're going to spend this much money," Acosta said, "you have to ask, 'Is there a cheaper approach that will yield the same results in some patients, maybe other medications or surgery?'"

Larger studies are needed to assess the reliability of the "hungry gut" genetic profile in more diverse populations, the researchers said.

If the new results are confirmed, Acosta said, doctors can finally tell some of their patients, "'We know why you are struggling with obesity,' and we can say with confidence, 'This expensive drug will help you,' or, 'Hey, this might not be for you.'"

(Reporting by Nancy Lapid; editing by Michele Gershberg and Will Dunham)