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

on Monday its experimental drug to treat a rare obesity disorder

met the main goal in a late-stage trial.

The therapy setmelanotide showed a significant reduction in

body mass index in both adult and pediatric patients compared to

placebo, the company said.

The therapy is being tested to treat acquired hypothalamic

obesity, a rare form of obesity that occurs following damage to

the hypothalamic region of the brain.

Rhythm estimates there are 5,000 to 10,000 people living

with hypothalamic obesity in the U.S.

Setmelanotide is currently approved under the brand name

Imcivree to treat genetic obesity in adults and children aged

two years and older.