SAT-804 Comparison of Forteo and Teriparatide on Improvements in Bone Mineral Density

Abstract Disclosure: C. Crompton: None. K. Baum: None. M. Silvey: None. M. Al Mukaddam: None. Background: Teriparatide (Forteo®) is a biologic therapy recommended for use in the treatment of osteoporosis for patients at high or very high risk of fracture. Market exclusivity of Forteo® expired in October 2019 allowing for approval of biosimilars. A biosimilar of Forteo® was approved in the United States in October 2019 through the 505(B)(2) application. This application does not require those seeking approval to conduct safety and efficacy studies on their product for submission and allows submission of studies completed for the reference product instead. This pathway is a faster path to market compared to the biologic license application that is used for approval of generic products. The application for the biosimilar (teriparatide) included a study conducted by the manufacturer that compared change in lumbar spine BMD after 24 weeks in osteoporotic patients taking teriparatide or Forteo®. Results were not published due to limitations in the trial design. There is currently a lack of real-world data demonstrating equivalent safety and efficacy between Forteo® and teriparatide biosimilar. This retrospective study evaluated changes in BMD in osteoporotic patients treated with either Forteo® or teriparatide for 18-24 months. Methods: This retrospective chart review included osteoporotic patients ≥ 18 years of age who received teriparatide or Forteo® prescriptions from the practice location and initiated therapy between October 1, 2019 and October 31, 2022. Patients without DXA results at the conclusion of therapy or who did not complete at least 18 months of therapy were excluded. The primary endpoint was percent change from baseline in BMD of lumbar spine, femoral neck, and total hip. Data was analyzed using a two-tailed Mann-Whitney test with a significance level of 0.05. Results: A total of 108 patients were included: 27 (median age 67 years, 88.9% female) in the teriparatide group and 81 (median age 68 years, 85.2% female) in the Forteo® group.. There was no significant difference in median change from baseline BMD of lumbar spine (+9.6% vs +7.7%, P= 0.56), left femoral neck (1.5% vs 2.8%, P= 0.39), right femoral neck (+1.6% vs +4.4%, P= 0.14), left total hip (+2.4% vs +3.2%, P= 0.24), or right total hip (0.0% vs +1.4% , = 0.71) with teriparatide vs Forteo®, respectively. Adverse effects were reported in 7.4% of patients in teriparatide group and 9.9% of patients in the Forteo® group. Most reported adverse effects were constipation, nausea, and fatigue. Conclusion: In this small retrospective study, effect on bone mineral density and reported adverse events were similar between teriparatide and Forteo® when used for the recommended duration of therapy. Results contribute real-world data to support equivalent efficacy and safety of teriparatide and Forteo® formulations. Presentation: Saturday, July 12, 2025