FDA to Review Newly Developed Innovative Antibody for Osteoporosis Therapy


Amgen and UCB submitted a biologics license application (BLA) to U.S. Food and Drug Administration (FDA) for the investigational bone forming monoclonal antibody, romosozumab.

amgen logoThe BLA is for the approval of romosozumab as an osteoporosis therapy inucb biotech logo postmenopausal women who are at a high risk of fracture.

Osteoporosis is an age related disorder characterized by gradual loss of bone mass, bone density and degradation of bone tissue which causes increased bone fragility and risk of fracture. Osteoporosis does not have any particular symptom except the main event which is high risk of bone fractures.

Romosozumab also known as AMG 785 is a humanized monoclonal antibody which act as an inhibitor by binding to sclerostin which is a naturally occurring protein in the bone. Sclerostin is a glycoprotein secreted by osteocyte and it has anti-anabolic effects on the formation of bones.

Sclerostin is known to bind to LRP5/6 receptors and inhibit the Wnt signaling pathway. The inhibition of Wnt pathway causes decreased bone formation. Therefore, romosozumab helps in increasing bone formation and decreasing bone resorption by inhibiting sclerostin.

romosozumab mechanism of action

Figure 1. Molecular mechanism of romosozumab (photo credit:

The antibody was originally developed by CellTech which is presently owned by UCB. Celltech in 2012 partnered with Amgen for the development of the product.

The BLA was filed after a complete pivotal Phase III clinical trial conducted by AMGEN and UCB. The clinical study named as FRAME (FRActure study in postemenopausal woMen with ostEoporosis) was conducted in approximately 7200 patients to evaluate efficiency of romosozumab against placebo in postmenopausal women with osteoporosis. The results of the trial will be presented in the upcoming medical congress.

The adverse effects were also found to be very mild. Majority of the patients faced effects like arthralgia and nasopharyngitis during the trial process.

Osteoporosis is a chronic disease, largely asymptomatic, and often undetected until a fragility fracture occurs. Many patients often view fragility fractures as part of aging, but these fractures are an indication of a weakened skeleton and a signal for intervention with medication,” said Dr. Pascale Richetta, head of bone and executive vice president, UCB. “We are pleased to submit the first regulatory submission for romosozumab and are committed to seeking global regulatory approvals in the hopes of making this important therapy available for appropriate patients at increased risk of fracture.”

More than 54 million Americans have low bone mass thus increasing the risk of osteoporosis. Studies suggest that one in every two women and nearly one in every four men in the age range 50 or more are at risk of breaking a bone as a direct result of osteoporosis. More than 10 million osteoporosis cases are found in India alone. Out of such high number of at-risk patients, very less percentage of the patients receives an actual treatment for osteoporosis due to lack of any significant symptoms.

Till date, there is no cure for osteoporosis. Osteoporosis can be either reduced or prevented but cannot be cured completely. If romosozumab is granted the approval, it is going to be the ‘first of its kind’  medicine that will be able to treat osteoporosis from the origin rather than just reducing or preventing it.

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