SAT-785 - Prolonged Teriparatide Osteoporotic Therapy in Two Patients with High Risk of Fractures

Teriparatide (TPTD) is a recombinant human parathyroid hormone and bone anabolic agent used for the treatment of osteoporosis (OP) in patients with a high risk for fractures (Fx). Previously, the U.S. Food and Drug Administration (FDA) limited the cumulative duration of medication use to two years over a patient’s lifetime due to a theoretical human risk of osteosarcoma based on animal studies. However, in 2020 the FDA updated its prescribing information based on postmarketing surveillance studies examining osteosarcoma risk in patients with TPTD exposures and thus removed the boxed warning. However, there are no clear recommendations on possible duration of TPTD use and safety profile beyond 2 years. The proposed indications for prolong TPTD use are very high Fx risk, unable to come off glucocorticoid therapy, high risk Fx with P1NP level that remains elevated after 2 years of therapy, multiple vertebral Fx at baseline but none while on TPTD, adynamic renal bone disease, severe COPD and vertebral Fx (VF). We present two patients who remain on prolonged TPTD therapy for more than five years, who remain with multiple stable VFs and improved bone mineral density (BMD) based on dual-energy x-ray absorptiometry (DXA) evaluation.

Case Presentation:
The first patient is a 75-year-old female with severe OP, VFs T6-T10 and L1-L5, and myasthenia gravis complicated by severe exacerbations with muscle weakness and recurrent falls, who has been on TPTD since 2020 until now and declined medication cessation due to no recurrent Fx while on therapy. No new or worsening VFs have been seen on follow up imaging during the TPTD therapy. The bone formation marker P1NP remains elevated. Additionally, DXA scan revealed a significant increase in lumbar spine BMD of 19.2% and significant increase in left hip BMD of 13.6%. Of note, she continues to experience recurrent falls without any new fractures.
The second patient is an 83-year-old male who was initiated on TPTD also in 2020 for OP with multiple VFs and due to being a continued high risk for fracture, remains on therapy. DXA scan showed lumbar spine BMD increase of 11.9% from a baseline prior to TPTD therapy and left hip BMD increase of 6.7% from baseline. Multiple VFs T11, T12, and L1-L5 remain stable on CT imaging. His P1NP returned to baseline and patient will proceed with consolidation therapy.

Conclusion:
Data regarding the use of TPTD for a duration longer than two years is limited but may be beneficial in patients with high risk of OP fractures. We present two patients on TPTD therapy for more than five years with multiple stable VFs on therapy with improvement in BMD and no side effects.

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