Results showed odanacatib significantly increased BMD compared to placebo
In the odanacatib group, BMD changes from baseline at 24 months were significantly different versus placebo at all three hip sites (+1.73%, +1.83%, +0.83% for the femoral neck, hip trochanter, and total hip, respectively, vs. -0.94%, -1.35%, -1.87% with placebo), and the lumbar spine (+2.28% vs. -0.30% change with placebo). At the distal forearm, BMD changes from baseline at 24 months were -0.92% and -1.14%. The difference versus placebo at the distal forearm (+0.22%) was not statistically significant.
The overall incidence of adverse events, including those that were considered drug-related or serious, were similar between treatment groups. Treatment discontinuations due to adverse events were 9.0 percent for patients receiving odanacatib and 3.3 percent for patients receiving placebo. The most common clinical adverse events in patients receiving odanacatib and placebo, respectively, were urinary tract infection (11.5%, 16.5%), back pain (11.5%, 9.9%), arthralgia (9.0%, 9.9%), fractures (4.9%, 13.2%), bronchitis (5.7%, 4.1%), nasal pharyngitis (3.3%, 5.8%), and upper respiratory infection (4.1%, 0.8%).
About OdanacatibIn osteoporosis, bone loss occurs because of an imbalance in bone remodeling (the rate of bone resorption exceeds that of bone formation). Osteoclasts, cells that resorb bone, secrete signaling factors to stimulate osteoblasts, cells that form bone. Odanacatib selectively inhibits cat-K, the primary enzyme in the osteoclasts that digests proteins during bone resorption. Progressive increases in bone mineral density have been demonstrated with odanacatib. In July 2012, Merck announced it planned to begin closing the Phase III trial assessing fracture risk reduction with odanacatib, at the recommendation of the study’s Data Monitoring Committee (DMC), after its first planned interim analysis showed robust efficacy and a favorable benefit-risk profile. The DMC noted that safety issues remain in certain selected areas and made a recommendation with respect to following up on them. Merck's previously announced plan to conduct a blinded extension trial will allow further monitoring of the issues. The extension trial will also continue to measure efficacy.