Biosimilars expand access to osteoporosis treatment

Interview with Professor Yoo Mee Kim, Department of Endocrinology and Metabolism, Catholic Kwandong University International St. Mary’s Hospital

Beyond bone density to ‘fracture risk’…diagnostic paradigm changing

Introduction of biosimilars…expectations rise on improved access to osteoporosis treatment

The paradigm for osteoporosis treatment is shifting. There is a growing recognition that the condition should be approached as a ‘long-term management disease’ aimed at preventing fractures and maintaining quality of life, rather than merely slowing the decline in bone density. In particular, with the recent emergence of denosumab biosimilars improving treatment access, changes are being detected in the market as well.

Professor Yoo Mee Kim of the Department of Endocrinology and Metabolism at Catholic Kwandong University International St. Mary’s Hospital emphasized, “Osteoporosis has almost no symptoms, so it is often first detected as a fracture before patients even realize they have the condition. Prevention and early treatment before fractures occur are most important.”

Professor Kim has been serving as president of the Korean Society for Bone and Mineral Research since January 2026. She graduated from Yonsei University College of Medicine and earned her master’s and doctoral degrees from the same university. She currently heads the Endocrinology and Diabetes Center at International St. Mary’s Hospital. She is an active member of the Korean Endocrine Society, Korean Diabetes Association, Korean Society for the Study of Obesity, and other organizations.

Professor Yoo Mee Kim. Director of the Endocrinology and Metabolism Center at International St. Mary’s Hospital

Osteoporosis progresses without symptoms…fracture is the first signal

An osteoporotic fracture refers to a fracture that can occur even with a minor impact. It can even occur from a mild fall or coughing. If such a fracture occurs, it is necessary to suspect osteoporosis and undergo testing.

Professor Kim explained, “Since osteoporosis causes no specific symptoms even as bones weaken, patients are often unaware of their condition. Consequently, many cases are only discovered after fractures occur in the wrist, spine, or hip.”

The problem is what happens after a fracture. It does not simply end with a broken bone. She said, “When a fracture occurs, activity levels drop sharply and can lead to muscle loss and worsening chronic diseases. In elderly patients, reduced immunity may also increase the risk of complications such as pneumonia.”

Hip fractures, in particular, are directly linked to survival. Professor Kim said, “When a hip fracture occurs in the elderly, it can lead to long-term hospitalization and complications, greatly increasing mortality. Even if a relatively minor fracture, such as a wrist fracture, occurs, it already means that the bones have weakened. Because fractures often begin at the wrist and progress to the spine and hip, early response is extremely important.”

Osteoporosis increases sharply among women and after the 50s…menopause is a key variable

Osteoporosis is particularly common in women. Professor Kim explained, “Female hormones play a role in protecting bones, but after menopause, hormone levels drop sharply, and bone loss progresses rapidly. From the 50s onward, prevalence and fracture risk increase significantly.”

Recently, due to the aging population, the incidence of osteoporosis in men has also been on the rise. However, because hormonal decline occurs gradually in men, the onset of the disease tends to be slower than in women.

Osteoporosis is diagnosed through Dual-energy X-ray absorptiometry (DXA). If a fracture has already occurred, or if there are factors such as advanced age, low body weight, family history, chronic disease, or polypharmacy, the patient is classified as high risk even if bone density is relatively good.

Professor Kim emphasized, “Osteoporosis is diagnosed when the T-score, which indicates the degree of bone density loss compared with young adults, is -2.5 or lower. However, it is important to evaluate fracture risk alongside bone density measurements rather than relying solely on bone density values.”

A shift in treatment paradigms… now capable of improving bone density

In the past, osteoporosis treatment focused primarily on slowing progression. Today, major treatment options have diversified to include bisphosphonates, denosumab, and anabolic agents (PTH analogs, romosozumab).

Bisphosphonates have long been the first-line treatment. Currently, denosumab-based formulations account for over 40% of the total osteoporosis treatment market share.

Denosumab is characterized by a stronger effect through a mechanism that blocks bone resorption by inhibiting osteoclast formation. Since the emergence of denosumab, many changes have occurred in the osteoporosis treatment market.

Professor Kim said, “While existing treatments were limited to slowing bone density loss, the recent emergence of more potent drugs has made it possible to actually increase bone density.”

Daewoong Pharmaceutical’s osteoporosis treatment Stoboclo

Emergence of biosimilars…raises expectations for improved treatment access

Recently, Prolia (denosumab) biosimilar ‘Stoboclo’ has been rapidly gaining traction in the market. It was first launched in March 2025. While the original drug exceeded KRW 200,000 when it first received reimbursement, Stoboclo was launched at about KRW 100,000, roughly half that level.

When insurance reimbursement is applied, the actual cost borne by patients is only about KRW 180 per day and about KRW 5,400 per month on average. As a result, it is widely regarded as having significantly improved patient access. Just 10 months after its launch, it has established itself in the market with cumulative sales of KRW 11.8 billion.

Professor Kim said, “If a drug has similar efficacy and safety, cost burden ultimately becomes an important factor from the patient’s perspective. Because osteoporosis treatment must be continued for a long period, a lower drug cost can have a positive impact on treatment persistence.”

She continued, “Osteoporosis is not merely a disease of aging but a condition requiring active management. Preventing fractures through early diagnosis and continued treatment is of the utmost importance.”