Sept 1 (Reuters) - Amgen Inc said its experimental bone drug was found to be more effective than an already marketed drug in a late-stage study.

Amgen's drug, romosozumab, met the main goal of showing a significant difference over teriparatide in improving total hip bone density by the 12th month in postmenopausal women with osteoporosis.

Osteoporosis is a condition which causes bones to become weak and brittle leading to an increased risk of fracture.

(Reporting By Samantha Kareen Nair in Bengaluru; Editing by Maju Samuel)