Positive results have been reported from a phase III study of romosuzumab (Amgen/UCB), an investigational bone-forming monoclonal antibody, in postmenopausal women with osteoporosis.

The STRUCTURE (STudy Evaluating the Effect of RomosozUmab Compared With Teriparatide in PostmenopaUsal Women With Osteoporosis at High Risk for Fracture PReviously Treated With BisphosphonatE Therapy) trial was an international, randomized, open-label, teriparatide-controlled study that evaluated the safety, tolerability, and efficacy of romosozumab in 436 subjects previously treated with bisphosphonate therapy. The subjects received either subcutaneous romosozumab (210 mg monthly) or subcutaneous teriparatide (20 mcg daily) for 12 months.

The study met its primary endpoint, demonstrating a statistically significant difference in favor of romosozumab in the percent change in total hip bone-mineral density (measured by dual-energy x-ray absorptiometry [DXA]) through month 12.

The most common adverse events in the romosozumab arm included nasopharyngitis, arthralgia, back pain, headache, and falls.

Romosozumab inhibits the protein sclerostin, thereby increasing bone formation and decreasing bone breakdown. A global phase III program evaluating the safety and efficacy of romosozumab includes two large fracture trials that are comparing romosozumab with either placebo or an active comparator in more than 10,000 postmenopausal women with osteoporosis. First results from the phase III FRAME trial are expected in early 2016.

About half of all women over 50 years of age will have an osteoporosis-related fracture in their remaining lifetime. In addition, patients with a previous hip fracture have a threefold greater risk of a subsequent fracture within 2 years.

Source: Amgen, Inc.; September 1, 2015.