Economic evaluations of adjunctive osimertinib treatment in surgically resected epidermal growth factor receptor-positive (EGFR+) non-small cell lung cancer (NSCLC): Analysis for stage 2 disease.

Abstract

e20506 Background: Following surgical resection, patients with NSCLC require monitoring due to the risk of recurrence. Studies have demonstrated the clinical benefit of osimertinib, a tyrosine kinase inhibitor, as adjunctive therapy in surgically resected EGFR+ NSCLC, including in stage 2 disease. We performed a cost effectiveness/utility analysis of adjunctive osimertinib therapy in stage 2 disease following surgical resection. Methods: A two state partitioned survival model differentiating disease free survival (DFS) from disease recurrence and death was specified (US payer perspective). Parametric functions were fit to digitized overall survival (OS) and DFS curves. A 5 year time horizon was specified, with a 3% discount rate applied to costs and utilities beyond year 1. Costs of treatment (wholesale acquisition cost), adverse events (grade 3/4 except all grades for immunotherapy related AEs), and monitoring were sourced from, respectively, Redbook, literature, and Physician Fee Schedules (US $2021). DFS life years (DFSLY) and quality adjusted life years (DFSQALY), incremental cost effectiveness/utility ratios (ICER/ICUR) in terms of DFSLY and DFSQALY gained (g) were estimated in base case analyses (BSA) and probabilistic sensitivity analyses (PSA). Results: Exponential regression was used to extrapolate osimertinib and placebo Kaplan-Meier curves. As detailed below, in BCA (PSA) the incremental cost of osimertinib over placebo was $778,315 ($778,202). The incremental DFSLY was 1.740 (1.738), which yielded ICER of $447,349/DFSLYg ($447,768/DFSLYg). The incremental DFS QALY was 1.234 (1.232), yielding ICUR of $630,910/DFSQALYg ($631,498/DFSQALYg). Conclusions: As to disease recurrence in stage 2 surgically resected EGFR+ NSCLC, our model associated adjunctive osimertinib therapy with incremental clinical gains of 1.740 (1.738) DFSLY and 1.234 (1.232) DFSQALY compared to placebo, however at marked incremental cost. As adjunctive osimertinib treatment is indicated in EGFR+ NSCLC disease stages 1B and 3A, the present stage 2 cost effectiveness/utility results should be compared to those for stages 1B and 3A.[Table: see text]