Amgen’s recent positive Phase III results for an antibody drug is putting it neck and neck with Radius Health’s peptide — the latest in a batch of osteoporosis therapies edging their way to the market. The current widely prescribed generic — bisphosphonate — only works to slow the loss of bone, while these newer drugs add to the therapies that aim to rebuild.
Osteoporosis is the loss of bone density which causes bones to become weak, brittle, and easily broken. In healthy people, bone is constantly being broken down and replaced. When bone is broken down more quickly than it is replaced, osteoporosis occurs. As the disease progresses, patients become more vulnerable to broken bones, especially in the hip, spine, and wrist. In advanced cases, even minor falls or bumps can result in a fracture, leading to loss of mobility.
According to the National Osteoporosis Foundation, osteoporosis-related fractures number as many as two million per year in the US, with related costs at $19 billion. These numbers are expected to climb to three million and $25.3 billion, respectively, by 2025. Let’s break down how bone loss occurs, which therapies are currently on the market, and which ones in the pipeline are threatening to become the new gold standard for osteoporosis care.
BONE FORMATION 101
Bone formation and maintenance is a complex process that relies on many different interacting factors but is driven by two specific cell types: osteoblasts, which lay down bone tissue, and osteoclasts, which degrade bone tissue. This process may be activated when bone remodeling is required, such as in response to a fracture. Osteoclasts break down the damaged bone tissue by secreting an acidic substance in a process known as bone resorption, and then osteoblasts produce new tissue for bone formation. During childhood, formation exceeds resorption; as people age, resorption begins to exceed formation.