2378 - Savings and the Opportunity for Expanded Treatment Access with Advent Biosimilar Denosumab: A U.S. Perspective

Purpose/Objective(s): Denosumab is a RANKL inhibitor indicated to prevent skeletal-related events among patients with multiple myeloma and bone metastases from solid tumors. Although denosumab’s reference product (RP) is considered cost-effective from a United States (US) perspective, the cost of biologic treatments represent approximately half of medication expenditure; thereby straining the healthcare system. This study evaluated the cost savings associated with the advent of a denosumab biosimilar in a hypothetical plan covering 1-million members in the US.

Materials/Methods: Ex-ante analyses were conducted using US-specific data to parameterize the model with the following inputs, WAC prices (RP: $2945.28 per one 1.7 ML 120 MG pack in 2025) and recent incidence estimates for multiple myeloma, metastatic lung, breast, and prostate cancer. The assumed dosing was once every four weeks based on the RP’s label. The price for the denosumab biosimilar was tested via three discounting scenarios (50%, 75%, and 85%). Outputs from the model were the direct cost-savings associated with drug acquisition (total and per-member-per-month [PMPM]). Two biosimilar market shares were tested, a more conservative estimate of 25% and a higher estimate of 75% (based on the historical 3-year oncology biosimilar adoption rates). The savings were modeled as the number of additional doses of denosumab and the number of stereotactic body radiation therapy (SBRT) sessions that could be realized (using the cost published in recent economic models), assuming budget-neutrality.

Results:

In a hypothetical plan covering 1-million lives, the most conservative estimate (50% biosimilar discount and 25% market uptake) demonstrated expected savings of $4.8 million ($0.40 PMPM). The savings would increase to $7.2 million ($0.60 PMPM) and $8.1 million (0.68 PMPM) if the biosimilar discount was 75% and 85%, respectively. Assuming a 25% market conversion, the number of additional doses for denosumab ranged from 3,250 to 18,416. In the higher biosimilar market share scenario of 75%, a 50% discount would create savings of $14.4 million (1.20 PMPM). Using a 75% and 85% biosimilar discount, savings were an estimated $21.5 million (1.79 PMPM) and $24.4 million (2.03 PMPM), respectively. The potential savings from the 75% conversion scenario would create an additional 9,750 to 55,250 doses of denosumab. There are several ways that the savings could be redistributed within the healthcare system. If the savings were instead used to provide additional rounds of SBRT, approximately 342 to 1,746 sessions of SBRT could be provided.

Conclusion: This study demonstrates the cost savings that could be realized with the use of a denosumab biosimilar. As the US healthcare system experiences increased demands to control spending, policies that encourage the uptake of available biosimilars could help to alleviate budget constraints.