Merck

(MRK) - Get Report

said a new study found its Fosamax osteoporosis drug produced more bone density improvement over one year than

Eli Lilly's

(LLY) - Get Report

competing Evista treatment.

The yearlong study compared a once-weekly, 70-miligram dose of Fosamax with a once-daily, 60-miligram dose of Evista. For the primary endpoint of percent change in bone mineral density in the lumber spine, Fosamax produced a 4.4% improvement, while Evista produced a 1.9% improvement, Merck said. The results were presented at the annual meeting of the American College of Obstetricians and Gynecologists.

In addition, the percentage of patients either maintaining or increasing bone mineral density at the lumbar spine was 94% for Fosamax compared with 75% for Evista at 12 months.

Merck's Fosamax sales totaled $812 million in its most recent first quarter.