Although the government extended the reimbursed period for denosumab-based osteoporosis treatments last year, concerns about reimbursement denials continue in practice.

Major medical societies, such as the Korean Endocrinology Society, have reached the point where they have issued guidelines to prevent insurance reimbursement cuts when prescribing treatments, raising awareness of the issue.

According to the medical community on the 11th, the Korea Endocrine Society recently analyzed cases of insurance reimbursement cuts for denosumab prescriptions and issued guidelines to prevent such cuts to frontline healthcare providers.

Previously, in May of last year, the Ministry of Health and Welfare expanded the reimbursement criteria for denosumab-based osteoporosis treatments, including Amgen's Prolia. The key change was that patients who had reached the treatment goal for osteoporosis—defined by their T-score—but remained at the borderline threshold, would continue to be eligible for reimbursement under the revised guidelines.

Under the revision, a patient who was initially eligible for reimbursement based on a bone mineral density (BMD) T-score of ≤ -2.5 and shows improvement during treatment to a T-score between -2.5 and -2.0, can receive continued reimbursement for an additional year—up to a maximum of two years.

The issue, however, lies in the increasingly strict reviews by the Health Insurance Review and Assessment Service (HIRA), which has led to a rise in reimbursement denials.

In fact, HIRA has introduced new review guidelines following the Ministry of Health and Welfare’s extension of the reimbursement criteria in 2023. These include specific principles regarding the use of osteoporosis drugs, particularly focusing on the interpretation of lumbar spine BMD results. HIRA clarified the evaluation method for ‘central bone’ in DXA (dual-energy X-ray absorptiometry) scans and established new review criteria for early denosumab administration.

The move appears to show the authorities’ intention to minimize confusion in reimbursement claims arising from the expanded coverage by providing more precise review standards to clinical practitioners.

The guidelines issued by the Korean Endocrine Society also closely align with these principles set by HIRA.

Specifically, the society emphasized in its preventive guidance that: ▲Selecting only two areas with the lowest T-scores is no longer acceptable, ▲ All measurable lumbar vertebrae from L1 to L4 must be included in the assessment.

Also, ▲the Exclusion of a specific vertebra requires a clear medical rationale, supported by radiographic evidence, and, ▲ clinicians must fully understand both the diagnostic criteria based on BMD interpretation and the insurance reimbursement requirements for prescribed treatments.

A representative from the Korean Endocrine Society stated, “Osteoporosis treatments are now being prescribed at local clinics and small hospitals, leading to a gradual increase in reimbursement cuts. Selecting only two vertebrae with the lowest T-scores for osteoporosis diagnosis is no longer acceptable. Unless there is a clear justification—such as a difference of more than 1.0 in T-scores compared to surrounding vertebrae, structural abnormalities, implants, or degenerative changes confirmed by radiographic imaging—all measurable lumbar vertebrae must be included in the bone density evaluation.”

They further explained, “Denosumab should be administered on a 180-day (6-month) schedule, and early administration is only permitted within 2 weeks of the due date. Follow-up BMD testing must be conducted at exact 365-day intervals, and if testing is performed earlier, reimbursement will generally not be allowed. In cases where early testing within 4 weeks is unavoidable, the reason must be clearly documented in the medical record. Otherwise, it may be subject to reimbursement denial.”

Meanwhile, following the expiration of Amgen's substance patent for its original denosumab-based therapy Prolia, biosimilar versions of the drug have entered the domestic clinical market. The first denosumab biosimilar, Stoboclo, has received reimbursement approval and is being co-marketed by Celltrion Pharm and Daewoong Pharmaceutical.

Samsung Bioepis is also set to enter the Korean denosumab market, preparing to launch its biosimilar Obodence in partnership with Hanmi Pharmaceutical.

As a result, intense competition in sales and marketing is expected between Amgen and its Korean partner Chong Kun Dang, Celltrion Pharm (with Daewoong), and Samsung Bioepis (with Hanmi), all vying for market share in the osteoporosis treatment market.