The study by a researcher at the University of Alabama at Birmingham showed that Forteo enhanced the bone density of the lumbar spine by 7.2 percent compared to 3.4 percent for patients who used the drug Fosamax.
Forteo, manufactured by the firm Eli Lilly, also bolstered hip bone density by 3.8 percent during 28 months of treatment compared to 2.4 percent of patients using Fosamax, which is produced by Merck.
The clinical trial was carried out over 18 months on 428 men and women from age 22 to 89, said the study published in the latest issue of the New England Journal of Medicine. The bone density measurements were taken at the outset and end of the trial by a low-level x-ray machine.
Forteo is currently used to treat osteoporosis in post-menopausal women, who experience a drop in estrogen levels that causes the destruction of bone tissue.
The study will likely help Eli Lilly's bid for US government approval to use the drug to treat osteoporosis caused by glucocorticoid, a strong anti-inflammatory often prescribed to reduce swollen joints from arthritis.
Doctors currently recommend bisphosphonates, a category of drugs that includes Fosamax, to treat people with osteoporosis induced by glucocorticoid.
Experts hope that Forteo represents a new class of drugs that can bolster bone density as well as minimize the risk of fractures in arthritis patients, said the lead author of the study, Kenneth Saag, a professor in the university's division of clinical immunology and rheumatology.