Abstract
Background: The phase 3 VIALE-A trial (NCT02993523) demonstrated that venetoclax plus azacitidine (VEN+AZA) improved overall survival (OS) and led to higher remission rates compared with AZA monotherapy, in patients with newly diagnosed (ND) acute myeloid leukemia (AML) who are ineligible for intensive chemotherapy. Based on the results from VIALE-A, VEN+AZA received full United States (US) Food and Drug Administration approval in October 2020 for patients with ND AML aged ≥75 years, or who were ineligible for intensive induction chemotherapy due to comorbidities. This study aims to assess the long-term cost-effectiveness value of the VEN+AZA regimen from the VIALE-A trial from a US third-party payer perspective.
Methods: A partitioned survival model with a 28-day cycle was developed to estimate costs and outcomes of treatment with VEN+AZA vs. AZA among patients with ND AML, who are ineligible for intensive chemotherapy, over a lifetime time horizon. The model included three health states: event-free survival (EFS), progressive/relapsed disease, and death. Within the EFS state, patients were further partitioned into time spent in complete remission (CR) or CR with incomplete marrow recovery (CRi), and time spent in non-CR/CRi. Efficacy inputs (OS, EFS, and CR/CRi rate) for both treatment arms were estimated using VIALE-A data. Best-fit parametric models per Akaike information criterion (AIC) were used to extrapolate OS until it reached EFS, and extrapolate EFS for each treatment until Year 5. Patients who remained in EFS after Year 5 were considered cured, and were assumed to have the same mortality as the US general population. Mean time on treatment (ToT) for both regimens was based on the time observed in VIALE-A. The costs for drug acquisition, drug administration for initial and subsequent treatments, subsequent stem cell transplant procedures, adverse events (AEs), and healthcare resource utilization (HRU) associated with each health state were obtained from the literature or publicly available data. All costs were inflated to 2021 US dollars. Utilities for each health state were estimated using EuroQol-5 dimension-5 level (EQ-5D-5L) data from VIALE-A, based on the US crosswalk value set. Information on disutilities due to Grade 3/4 AEs were obtained from the literature. Incremental cost-effectiveness ratios (ICERs) per life year (LY) and quality-adjusted life year (QALY) gained were estimated. Deterministic sensitivity analyses (DSA), scenario analyses and probabilistic sensitivity analyses (PSA) were performed to assess the robustness of the results.
Results: Over a lifetime time horizon, compared with AZA, VEN+AZA was associated with an increase of 1.89 LYs (1.10 vs. 2.99, respectively) and 1.45 QALYs (0.84 vs. 2.30, respectively). Patients in the VEN+AZA arm incurred higher total costs ($250,486 vs. $110,034 for patients in the AZA arm). The ICER for VEN+AZA vs. AZA was estimated to be $74,141 per LY gained, and $96,579 per QALY gained. Results from the DSA and scenario analyses supported the base-case findings, with ICERs ranging from $60,922 to $138,554 per QALY gained. The results were most sensitive to alternative approaches for ToT estimation, subsequent treatment HRU costs, cure time point, and the extrapolation approach for EFS. Results from PSA showed that compared with AZA, VEN+AZA was cost-effective in 99.9% of cases at a willingness-to-pay (WTP) threshold of $150,000.
Conclusions: Compared with AZA monotherapy, VEN+AZA results in a favorable ICER of $96,579 per QALY gained over a lifetime time horizon. The base-case results suggest that, compared with AZA, VEN+AZA is a cost-effective strategy based on a WTP threshold of $150,000 per QALY gained. Sensitivity analyses support the base-case results. Thus, VEN+AZA offers a cost-effective strategy in the treatment of patients with ND AML who are ineligible for intensive chemotherapy from a US third-party payer perspective.
Disclosures
Pratz: Agios: Consultancy; Abbvie: Consultancy, Honoraria, Research Funding; University of Pennsylvania: Current Employment; BMS: Consultancy, Honoraria; Novartis: Consultancy; Astellas: Consultancy, Honoraria, Research Funding; Cellgene: Consultancy, Honoraria; Millenium: Research Funding. Chai: Analysis Group, Inc.: Consultancy, Current Employment; Genentech, Inc.: Consultancy. Yin: Analysis Group, Inc.: Consultancy, Current Employment; Genentech, Inc.: Consultancy. Nie: Analysis Group, Inc.: Consultancy, Current Employment; Genentech, Inc.: Consultancy. Montez: Genentech, Inc: Current Employment, Other: May hold equity. Iantuono: Genentech, Inc.: Current Employment, Current equity holder in publicly-traded company, Divested equity in a private or publicly-traded company in the past 24 months. Downs: Genentech, Inc.: Current Employment, Current equity holder in publicly-traded company; F. Hoffmann-La Roche Ltd: Current equity holder in publicly-traded company. Ma: Genentech, Inc.: Current Employment, Other: May hold equity.
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