An Economic Model to Evaluate the Impact of Formulary Tier Increases for Apixaban on the Incidence and Cost of Clinical Events in Patients with Non-Valvular Atrial Fibrillation in the United States
Author(s)
Rupesh Subash, BSc, MSc1, Elisabeth Vodicka, MHA, PhD2, Serina Deeba, MPH2, Vasileios Vasilopoulos, MSc3, Carissa Dickerson, PhD3, Ewa Stawowczyk, PhD3;
1Pfizer Ltd., Walton Oaks, Surrey, United Kingdom, 2Pfizer Inc., New York, NY, USA, 3Health Economics and Outcomes Research Ltd., Cardiff, United Kingdom
1Pfizer Ltd., Walton Oaks, Surrey, United Kingdom, 2Pfizer Inc., New York, NY, USA, 3Health Economics and Outcomes Research Ltd., Cardiff, United Kingdom
Presentation Documents
OBJECTIVES: Within Medicare drug plans, treatments including direct oral anticoagulants (DOACs) (for reduction of stroke/systemic embolism (SE) risk in patients with non-valvular atrial fibrillation (NVAF)) are allocated a formulary ‘tier’ based on level of coverage provided. Formulary tier increases are associated with higher out-of-pocket costs to patients, often resulting in treatment switching and discontinuation. This study modeled the impact of a tier increase for apixaban on incidence and cost of clinical events in patients with NVAF in the US (Medicare perspective).
METHODS: A decision model was developed to evaluate incidence and cost of stroke/SE, major bleed (MB) and event-driven mortality in two scenarios (‘tier increase’ vs. ‘no tier increase’) over one year. Patients with ‘no tier increase’ were assumed to continue apixaban; patients with a ‘tier increase’ were assumed to continue apixaban, switch (to any DOAC [base-case 1] or rivaroxaban [base-case 2]), or discontinue treatment at rates of 57.5%, 12.4%, and 30.1%, respectively, based on Deitelzweig et al. Clinical inputs were sourced from Dhamane et al. (base-case 1) and Deitelzweig et al. (base-case 2). Costs were sourced from online databases and inflated to 2024 US dollars.
RESULTS: Based on a hypothetical cohort of 1,000,000 Medicare Fee-For-Service plan members, 47,036 patients with NVAF were identified to be receiving apixaban treatment. Using Dhamane et al. inputs, a tier increase for apixaban resulted in an additional 330 stroke/SEs, 58 MBs and 32 deaths, and $6,542,373 ($11.59 per patient/month; $0.55 per member/month) additional annual costs versus the ‘no tier increase’ scenario. Similar results were observed based on inputs from Deitelzweig et al., with an additional 257 stroke/SEs, 20 MBs and 25 deaths, and additional annual costs of $4,656,305 ($8.25 per patient/month; $0.39 per member/month).
CONCLUSIONS: A tier increase for patients with NVAF receiving apixaban was projected to increase clinical events and event-related costs for US Medicare payers.
METHODS: A decision model was developed to evaluate incidence and cost of stroke/SE, major bleed (MB) and event-driven mortality in two scenarios (‘tier increase’ vs. ‘no tier increase’) over one year. Patients with ‘no tier increase’ were assumed to continue apixaban; patients with a ‘tier increase’ were assumed to continue apixaban, switch (to any DOAC [base-case 1] or rivaroxaban [base-case 2]), or discontinue treatment at rates of 57.5%, 12.4%, and 30.1%, respectively, based on Deitelzweig et al. Clinical inputs were sourced from Dhamane et al. (base-case 1) and Deitelzweig et al. (base-case 2). Costs were sourced from online databases and inflated to 2024 US dollars.
RESULTS: Based on a hypothetical cohort of 1,000,000 Medicare Fee-For-Service plan members, 47,036 patients with NVAF were identified to be receiving apixaban treatment. Using Dhamane et al. inputs, a tier increase for apixaban resulted in an additional 330 stroke/SEs, 58 MBs and 32 deaths, and $6,542,373 ($11.59 per patient/month; $0.55 per member/month) additional annual costs versus the ‘no tier increase’ scenario. Similar results were observed based on inputs from Deitelzweig et al., with an additional 257 stroke/SEs, 20 MBs and 25 deaths, and additional annual costs of $4,656,305 ($8.25 per patient/month; $0.39 per member/month).
CONCLUSIONS: A tier increase for patients with NVAF receiving apixaban was projected to increase clinical events and event-related costs for US Medicare payers.
Conference/Value in Health Info
2025-05, ISPOR 2025, Montréal, Quebec, CA
Value in Health, Volume 28, Issue S1
Code
EE510
Topic
Economic Evaluation
Disease
SDC: Cardiovascular Disorders (including MI, Stroke, Circulatory)