Positive Results Reported From Late-Stage Study of Romosozumab in Men With Osteoporosis

Bone-forming monoclonal antibody inhibits sclerostin

Positive findings have been announced from a pivotal phase 3 trial of romosozumab (Amgen/UCB) in men with osteoporosis. The study met its primary endpoint, demonstrating a statistically significant increase in bone mineral density (BMD) at the lumbar spine (as assessed by dual-energy x-ray absorptiometry) in patients treated with romosozumab compared with those given placebo at 12 months.

All secondary endpoints comparing romosozumab with placebo were also met. Patients receiving romosozumab experienced a statistically significant increase in BMD at the femoral neck and total hip at 12 months and a statistically significant increase in BMD at the lumbar spine, femoral neck, and total hip at six months, compared with those receiving placebo.

Romosozumab is an investigational bone-forming monoclonal antibody and is not approved by any regulatory authority for the treatment of osteoporosis. It is designed to work by inhibiting the protein sclerostin and has a dual effect on bone, both increasing bone formation and decreasing bone breakdown. Romosozumab is being studied for its potential to reduce the risk of fractures in a global phase 3 development program. The program includes two large fracture trials comparing romosozumab with either placebo or an active comparator in more than 10,000 postmenopausal women with osteoporosis.

In the Placebo-Controlled Study Evaluating the Efficacy and Safety of Romosozumab in Treating Men With Osteoporosis (BRIDGE), 245 men were randomly assigned to receive either subcutaneous romosozumab (210 mg) or matched placebo every month for the duration of the 12-month treatment period.

The most frequently reported adverse events (AEs) in the romosozumab arm included nasopharyngitis, back pain, hypertension, headache, and constipation. Injection-site reactions were reported in 5.5% of patients in the romosozumab group compared with 3.7% of patients in the placebo group during the 12-month treatment period. The rates of positively adjudicated cardiovascular serious AEs and cardiovascular death were 4.9% and 0.6%, respectively, in the romosozumab group compared with 2.5% and 1.2% in the placebo group.

Source: Amgen; March 21, 2016.