MODELING THE LIFETIME BENEFITS OF ETEPLIRSEN IN PATIENTS WITH DUCHENNE MUSCULAR DYSTROPHY
Author(s)
Lauren Sedita, MS, Alexa Klimchak, MA, Katherine Gooch, PhD;
Sarepta Therapeutics, Inc., Cambridge, MA, USA
Sarepta Therapeutics, Inc., Cambridge, MA, USA
OBJECTIVES: Eteplirsen is a treatment for patients with Duchenne muscular dystrophy (DMD) amenable to exon 51 skipping. Real-world evidence (RWE) from external control studies have shown that eteplirsen slows time to loss of ambulation (LoA) and delays mortality. This study aimed to model potential lifetime eteplirsen benefits on disease progression in 5-year-old early ambulatory (EA) patients amenable to exon 51 skipping.
METHODS: A partitioned survival model over a lifetime horizon was built with four DMD health states (EA, late ambulatory, early non-ambulatory, late non-ambulatory), starting at age 5 in EA. Relative efficacy of eteplirsen plus standard of care (SoC; corticosteroids/medical management) was obtained from two published RWE studies, which estimated that eteplirsen reduces LoA hazard by 62% (hazard ratio, HR=0.38) and mortality hazard by 69.7% (HR=0.303) versus external controls. The age-specific risk of progression under SoC aligned with a previously published lifetime DMD model; LoA risk was adapted for corticosteroid-treated exon 51 skip-amenable patients based on data available from the Cooperative International Neuromuscular Research Group registry. Patient utility was based on US DMD patient-reported data using the Health Utilities Index-2 (HUI-2). Outcomes included ambulatory years gained, life years (LYs) gained, and equal value of life years gained (evLYG). Results were undiscounted (base case) and discounted at 1.5% and 3% annually (scenarios).
RESULTS: EA patients treated with eteplirsen plus SoC remained in ambulatory health states for 13.77 years versus 9.12 years for SoC alone, representing 4.65 ambulatory years gained (1.5% discounting, 3.76 years; 3% discounting, 3.08 years). Eteplirsen-treated patients also gained 13.28 LYs (1.5% discounting, 8.14 LYs; 3% discounting, 5.21 LYs) and 13.99 evLYG (1.5% discounting, 9.10 evLYG; 3% discounting, 6.21 evLYG) versus SoC only.
CONCLUSIONS: This model complements the totality of RWE for eteplirsen by estimating potential lifetime benefits in patients initiating treatment at an early age, increasing ambulatory time and extending survival.
METHODS: A partitioned survival model over a lifetime horizon was built with four DMD health states (EA, late ambulatory, early non-ambulatory, late non-ambulatory), starting at age 5 in EA. Relative efficacy of eteplirsen plus standard of care (SoC; corticosteroids/medical management) was obtained from two published RWE studies, which estimated that eteplirsen reduces LoA hazard by 62% (hazard ratio, HR=0.38) and mortality hazard by 69.7% (HR=0.303) versus external controls. The age-specific risk of progression under SoC aligned with a previously published lifetime DMD model; LoA risk was adapted for corticosteroid-treated exon 51 skip-amenable patients based on data available from the Cooperative International Neuromuscular Research Group registry. Patient utility was based on US DMD patient-reported data using the Health Utilities Index-2 (HUI-2). Outcomes included ambulatory years gained, life years (LYs) gained, and equal value of life years gained (evLYG). Results were undiscounted (base case) and discounted at 1.5% and 3% annually (scenarios).
RESULTS: EA patients treated with eteplirsen plus SoC remained in ambulatory health states for 13.77 years versus 9.12 years for SoC alone, representing 4.65 ambulatory years gained (1.5% discounting, 3.76 years; 3% discounting, 3.08 years). Eteplirsen-treated patients also gained 13.28 LYs (1.5% discounting, 8.14 LYs; 3% discounting, 5.21 LYs) and 13.99 evLYG (1.5% discounting, 9.10 evLYG; 3% discounting, 6.21 evLYG) versus SoC only.
CONCLUSIONS: This model complements the totality of RWE for eteplirsen by estimating potential lifetime benefits in patients initiating treatment at an early age, increasing ambulatory time and extending survival.
Conference/Value in Health Info
2026-05, ISPOR 2026, Philadelphia, PA, USA
Value in Health, Volume 29, Issue S6
Code
EE241
Topic
Economic Evaluation
Disease
SDC: Musculoskeletal Disorders (Arthritis, Bone Disorders, Osteoporosis, Other Musculoskeletal), SDC: Pediatrics, SDC: Rare & Orphan Diseases, STA: Multiple/Other Specialized Treatments