MON-792 Extended Teriparatide Therapy: A Case Study of Continued Bone Density Improvement in Postmenopausal Osteoporosis

Abstract Disclosure: J. Hansen: None. G. Woods: Corcept Therapeutics, Alexion Pharmaceuticals, Inc.. Teriparatide is a PTH-analog initially FDA approved in 2002 for the treatment of osteoporosis. Due to a signal of increased risk of osteosarcoma in rat models, initial human trials limited exposure to an average of 19 months, and the drug was then approved with a 24-month lifetime use limit. Post-marketing surveillance studies did not show an increased risk of osteosarcoma, and in November 2020 the 2-year limit was lifted. In the absence of clinical trial efficacy data, the question remains if extending treatment will continue to improve bone mineral density (BMD), reduce fracture risk, and/or demonstrate an increase in side effects. We present a case of continued improvement in BMD in a postmenopausal woman with osteoporosis with >4 years of continuous treatment with teriparatide. A 66 year old woman presented to endocrinology clinic following an L1 spinal compression fracture after a ground level fall. Her DXA bone density scan was notable for L2-L4 BMD of 0.66g/cm2 (T-score -4.2). Clinical risk factors for osteoporosis include maternal history of osteoporosis. Laboratory evaluation for secondary causes of osteoporosis was unrevealing. She started teriparatide 20 mcg daily in August 2020. Her bone density improved over the course of 2 years, but T-scores remained < -2.5. Due to her strong preference to continue teriparatide rather than transition to another treatment, she has continued teriparatide for 4 years and 5 months to date. At 3 years 10 months of treatment, her lumbar spine bone density improved to 0.883 g/cm2 (T-score -2.6) and procollagen I intact N-terminal propeptide (P1NP) remains elevated at 214 ug/L. Trabecular bone score (TBS) did not improve . She has not sustained any fractures since starting teriparatide. Side effects have included minor injection site bleeding. This case demonstrates continued improvement in bone density with extended teriparatide use beyond two years in a postmenopausal woman with osteoporosis complicated by vertebral fracture. After nearly four years of treatment, the patient's lumbar spine BMD improved by 22.4% (T-score improved from -4.2 to -2.6) and left total hip improved by 11.0% (T-score -2.5 to -2.0) without significant adverse effects. These findings suggest potential benefits of extended teriparatide therapy, highlighting the need for additional studies to further define the safety and efficacy of extended use. Presentation: Monday, July 14, 2025