Romosozumab Appears Safe and Effective in Women With Postmenopausal Osteoporosis: Presented at ASBMR

By Matt Silver

SAN FRANCISCO -- October 14, 2015 -- Romosozumab treatment is well tolerated and results in rapid and significant gains in bone mineral density compared with placebo in Japanese women with postmenopausal osteoporosis, according to a study presented here at the 37th Annual Meeting of the American Society for Bone and Mineral Research (ASBMR).

Hideaki Ishibashi, MD, Ina Hospital, Japan, presented the study on October 12.

Romosozumab, a sclerostin inhibitor, has a positive dual effect on bone mineral density, leading to increased bone formation and decreased bone resorption. However, the optimal dosage needs to be identified.

In this phase 2 study, researchers assessed the efficacy and safety of romosozumab in 252 postmenopausal Japanese women aged 55 to 85 years with mean dual-energy x-ray absorptiometry T scores of -2.7, -1.9, and -2.3 for lumbar spine, total hip, and femoral neck, respectively.

All patients were randomised to receive placebo or subcutaneous romosozumab 70, 140, or 210 mg monthly for 12 months.

At 12 months, all romosozumab doses significantly increased bone mineral density compared with placebo at each of the 3 skeletal sites. The greatest effects were seen with the 210-mg dose, which resulted in density gains from baseline of 16.9%, 4.7%, and 3.8% at the lumbar spine, total hip, and femoral neck, respectively.

All doses of romosozumab increased procollagen type 1 amino-terminal propeptide (P1NP) and reduced collagen type 1 cross-linked C-telopeptide (CTX) compared with placebo by week 1. P1NP levels reached a peak at 1 month, with a median increase of 101.1%, and fell below placebo levels by 12 months in the 210-mg group. CTX levels reached their lowest point at 1 week (median decline, 45.6%) and remained below the placebo level at 12 months.

The incidence of adverse and serious adverse events was similar between the groups. There was a statistically insignificant difference in mild-to-moderate osteoarthritis adverse events (6.9% romosozumab vs 0% placebo) and mild injection-site reactions (3.7% romosozumab vs 1.6% placebo).

Global phase 3 studies evaluating the monthly 210-mg dose for the treatment of osteoporosis are under way.

Funding for the study was provided by Amgen Inc. and UCB Pharma.

[Presentation title: Effects of Romosozumab in Japanese Women With Postmenopausal Osteoporosis: Phase 2 Trial Results. Abstract FRO331]

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