Amgen announced new long-term data showing that during the fourth and fifth years of Prolia (denosumab) treatment, postmenopausal women with osteoporosis receiving Prolia continued with further, statistically significant, year-over-year increases in lumbar spine and total hip bone mineral density (BMD), a key measurement of bone strength. The overall adverse event profile was similar for the fourth and fifth years of consecutive Prolia treatment.

The data, which were presented at the annual European Congress Osteoporosis and Osteoarthritis (ECCEO11-IOF) in Valencia, Spain, showed that treatment with Prolia, the first and only approved RANK Ligand inhibitor for the treatment of postmenopausal osteoporosis, resulted in robust BMD gains after five continuous years of treatment (13.7 per cent for lumbar spine BMD and 7.0 per cent for total hip BMD).

The pivotal FREEDOM (Fracture REduction Evaluation of Denosumab in Osteoporosis every 6 Months) study established the efficacy and safety of Prolia based on three years of data from approximately 7,800 postmenopausal women. The open-label extension of FREEDOM is evaluating the long-term (up to 10 years) efficacy and safety of Prolia in 4,550 postmenopausal women. Seventy percent of eligible women from the FREEDOM study continued enrollment in the extension study; 2,343 women continued to receive Prolia treatment, and 2,207 transitioned from placebo to Prolia.

Continued treatment with Prolia resulted in consistent year-over-year gains in BMD at the lumbar spine and total hip. In years 4 and 5 respectively, women taking Prolia experienced further 1.9 percent and 1.7 per cent increases in lumbar spine BMD and further 0.7 per cent and 0.6 per cent increases in total hip BMD (all P<0.0001 compared with extension baseline).

The women who transitioned from placebo to Prolia in the extension study showed significant BMD increases during the first two years of Prolia treatment: 7.9 per cent increase in lumbar spine BMD and 4.1 per cent increase in total hip BMD (all P<0.0001 compared with extension baseline).

Rates of adverse events (AEs) were 83.4 per cent for women who continued on Prolia and 82.8 per cent for women transitioned from placebo to Prolia. Rates of serious AEs were 18.9 per cent and 19.4 per cent for the two groups respectively. Two subjects in the group that transitioned from placebo to Prolia had AEs adjudicated to osteonecrosis of the jaw (ONJ) that healed without further complications. One of these subjects continued Prolia, and one subject discontinued. No atypical femoral fractures were reported in either group.

Prolia is the first approved therapy that specifically targets RANK Ligand, an essential regulator of osteoclasts (the cells that break down bone).

Prolia is approved in the European Union (EU) for the treatment of osteoporosis in postmenopausal women at increased risk of fractures, and for the treatment of bone loss associated with hormone ablation in men with prostate cancer at increased risk of fractures.

Prolia is approved in the US for the treatment of postmenopausal women with osteoporosis at high risk for fracture, defined as a history of osteoporotic fracture, or multiple risk factors for fracture; or patients who have failed or are intolerant to other available osteoporosis therapy.

Prolia is available in 12 European countries, the US, Canada and Australia. Applications in the rest of the world are pending.

Prolia is administered as a single subcutaneous injection of 60mg once every six months.