Biotechnology company Amgen Inc. will release the results of the study on its osteoporosis drug candidate, denosumab, shortly after the market opens Tuesday, giving investors a clearer image of the effectiveness of their osteoporosis drug. Preliminary results of the study supported by Amgen showed that its experimental drug denosumab reduced the risk of osteoporosis and fracture in men with prostate cancer treated with drugs that cause bone loss. The drug targets a protein involved with bone-destroying cells called osteoclasts. Data from two studies of its denosumab were presented at the American Society of Bone and Mineral Research meeting in Montreal.

The studies compared Amgen’s osteoporosis drug candidate with Merck & Co.’s Fosamax. The first study, involving 504 postmenopausal women with osteoporosis, found that those who were given denosumab as an injection every six months increased bone density by about 2 percent compared with a 1 percent increase in women taking Fosamax.

The drug was also tested on more than 1,400 men with non-metastatic prostate cancer undergoing androgen deprivation therapy. After a three-year follow-up period, denosumab produced greater increase in bone mineral density at the lumbar spine and non-vertebral sites than a placebo. Side effects of the drug were minimal.

Denosumab is involved in one of the largest programs in Amgen’s history. The company currently has trials involving more than 19,000 patients globally.

The company should have all of data for its first denosumab filing with US regulators by the end of 2008 or early 2009. The drug could reach the market by 2010, Amgen said.