Amgen Presents Denosumab and Sclerostin Antibody Data

Amgen has announced the presentation of data at the American Society for Bone and Mineral Research (ASBMR) Annual Meeting highlighting its expertise in bone biology research and commitment to developing therapies that address the burden of bone disease.

The studies evaluated denosumab and a sclerostin antibody, two of the company's investigational therapies.

These antibodies target key proteins responsible for the regulation of bone destruction and formation.

"Amgen scientists are committed to fulfilling the promise of biotechnology by developing novel therapeutics aimed at improving bone health," said Willard Dere, M.D., senior vice president of Global Development and chief medical officer, Amgen.

"Our research has the potential to transform the scientific understanding of bone biology and the treatment of conditions associated with bone loss."

Denosumab is an investigational fully human monoclonal antibody that targets RANK Ligand, a primary mediator of the formation, function and survival of osteoclasts.

Results from a post-hoc exploratory analysis of an ongoing, multicenter, Phase 2 study, showed that subjects treated with denosumab subcutaneously, 60 mg twice yearly for up to 24 months, experience an improvement not only in bone mineral density (BMD) but also in parameters of hip structural analysis (HSA), a technique that estimates geometric properties of bone strength.

In the study, patients were evaluated with dual energy X-ray absorptiometry (DXA), the recognized measure for BMD.

The DXA scans were then analyzed with HSA software, providing an estimated measurement of bone geometry.

Specifically, denosumab therapy resulted in a 6.69 percent increase in the measure of cortical thickness at the femoral shaft; there was a 0.31 percent decrease, from baseline, in the placebo group (p less than 0.001).

In the open label alendronate cohort, there was a 1.82 percent increase in cortical thickness at the femoral shaft (p less than 0.041).

These results are consistent with previous reports highlighting the effects of denosumab at highly cortical sites; cortical bone, the dense outer shell of the skeleton, comprises approximately three-quarters of the total skeletal mass.

The full data from this study has been presented at the ASBMR meeting on September 19.

"Increasing thickness at highly cortical sites is an effective way to improve bone strength and mechanical integrity of the skeleton," said Thomas Beck, ScD, associate professor, The Johns Hopkins University. 

"These observations support the potential of targeting RANK Ligand to improve bone structural strength."

This analysis extended the previously-reported two-year results that demonstrated twice-yearly subcutaneous injections of denosumab (60 mg) increased BMD at the lumbar spine (7.4 percent), total hip (5.1 percent), femoral neck (4.6 percent), distal 1/3 radius (1.8 percent) and total body (2.6 percent) compared to placebo at 24 months.

Per protocol, the study concluded at 12 months; the post-12 month analyses are exploratory.

Amgen is also reporting on preclinical data for denosumab at the meeting. In this study, designed to evaluate the effects of denosumab administration in aged primates after estrogen depletion (OVX), researchers found that long-term denosumab administration (16 months) is associated with increases in the mass and density of cancellous and cortical bone.

Sixteen monthly injections of denosumab at 50 mg/kg resulted in significant increases from baseline in lumbar BMD (+12 percent); the OVX arm resulted in a -4.9 percent change and sham resulted in a +0.8 percent change in lumbar BMD (p less than 0.001 for both groups).

Total hip BMD was also increased with denosumab treatment (+7.4 percent); the OVX arm experienced a -7.4 percent change and the sham group experienced a -0.6 percent change in total hip BMD (p less than 0.01 for both groups).

Cortical bone mass (volumetric bone mineral content (BMC) measured by pQCT/ peripheral quantitative computed tomography) increased at the radial diaphysis with denosumab treatment (+1.3 percent); the OVX arm had a -5.6 percent change (p less than 0.001) and sham a -2.3 percent change (p less than 0.05).

In the osteoporosis setting, denosumab is being investigated as a twice-yearly subcutaneous injection and appears well-tolerated in clinical trials to date.

Occurrence of adverse events in a multicenter, Phase 2 dose-ranging trial was similar among the denosumab-, placebo-, and alendronate-treated groups with the exception of dyspepsia, which was more common among those receiving alendronate.

The most common adverse events among all groups were upper respiratory infection, joint pain, sore throat, back pain, and headache.

To date, no neutralizing antibodies have been observed and there have been no gastrointestinal or renal effects.

A sclerostin-neutralizing monoclonal antibody is being developed by Amgen and UCB, a Belgian-based biopharmaceutical company.

Sclerostin, a naturally occurring protein in the body, plays a critical role in controlling bone mass by inhibiting the activity of bone-forming cells called osteoblasts.

The investigational sclerostin antibody targets this key inhibitor of bone-forming cells.

In data featured at the annual ASBMR meeting, scientists presented preclinical results from a small study in which three sclerostin-neutralizing monoclonal antibodies were tested in primates.

The goal of the study was to evaluate the effects of sclerostin inhibition on bone and bone biology in young female cynomolgus monkeys.

Sclerostin-neutralizing antibodies were administered at 3, 10 and 30 mg/kg once-monthly over a two-month period.

Specific results in this particular study for the sclerostin antibody under development included increased total BMC at the distal radius (20 percent increase in BMC for the sclerostin antibody-treated, 10 mg/kg dose group at the two-month time point versus a one percent increase in BMC for the vehicle control group).

In relation to the vehicle control group, there was a 5.5-fold increase in the rate of bone formation in lumbar vertebrae for the sclerostin antibody-treated 30 mg/kg dose group in the first month.

By the end of the two-month study, the strength of lumbar vertebrae increased for the sclerostin antibody-treated, 30 mg/kg dose group (a 53 percent increase in peak load for the sclerostin antibody-treated group versus a vehicle-treated control group).

Peak load is one of several accepted measurements for assessing bone strength.

Safety and efficacy data will become available once the clinical development program is initiated.

As part of Amgen's commitment to developing potential treatments for osteoporosis, the company has initiated a large, comprehensive multicenter study of 6,000 postmenopausal women in the U.S. and Europe, entitled "Prospective Observational Scientific Study Investigating Bone Loss Experience (POSSIBLE)."

At the ASBMR meeting, baseline data were presented from this study which was designed to collect and analyze: the pattern of use of current osteoporosis therapies; patient-attributed side-effect rates for these therapies; patient-reported compliance rates; the associations among current treatment and health-related quality of life, treatment satisfaction, and resource utilization.