Because zoledronic acid has been authorised in the EU as Zometa for a number of years, the company presented the results of some studies carried out with Zometa, which were taken into account when assessing Aclasta.

For osteoporosis, Aclasta has been studied in three main studies. The first compared Aclasta with placebo (a dummy treatment) in almost 8,000 elderly women with osteoporosis, looking at the number of fractures in the spine and the hip over three years. The second study compared Aclasta with placebo in 2,127 men and women with osteoporosis who had recently broken their hip, and looked at the number of fractures over up to five years. The third compared one infusion of Aclasta with daily treatment with risedronate (another bisphosphonate) in 833 men and women with osteoporosis caused by glucocorticoids, and looked at the change in the density of the bones in the spine over a year. In these studies, the patients could take other medicines for osteoporosis, but not other bisphosphonates.

For Paget’s disease, Aclasta has been compared with risedronate in a total of 357 adults in two studies lasting six months. The patients received one infusion of Aclasta or they took risedronate once a day for two months. The main measure of effectiveness was the number of patients who responded to treatment, defined as blood levels of serum alkaline phosphatase (an enzyme involved in the breakdown of bone) returning to normal or falling at least three quarters of the way back to normal.