Nov 7 (Reuters) - Rhythm Pharmaceuticals ( RYTM ) said

on Friday the U.S. Food and Drug Administration has extended the

review period for expanded approval of its drug to treat a rare

form of obesity, caused due to brain damage, by three months.

The FDA extended the review of Imcivree from December 20 to

March 20, 2026, the company said.

Rhythm said the health regulator had in October requested

more efficacy data from a late-stage trial testing the drug in

patients with acquired hypothalamic obesity.

The condition is caused by damage to the hypothalamus in the

brain, often due to tumors, their treatment or other injuries.

The additional information has been deemed a 'major

amendment,' which allows for more time for the agency to review,

the company said.

The major amendment sought did not include any information

relating to the safety or manufacturing of Imcivree, chemically

known as setmelanotide, the drugmaker said, adding that no new

data was requested.

"We have every confidence that these additional

sensitivity analyses confirm the strength of the data and

setmelanotide's potential to benefit patients with hypothalamic

obesity," said CEO David Meeker.

In April, Imcivree

notably reduced

weight in patients with the form of obesity in a late-stage

trial with 120 patients.

The drug is currently approved to treat genetic obesity in

adults and children aged two years and older.