Cost-Effectiveness Analysis of Durvalumab in Limited-Stage Small Cell Lung Cancer in the United States

Small cell lung cancer (SCLC) is an aggressive neuroendocrine malignancy characterized by poor prognosis. The ADRIATIC trial demonstrated significant survival benefits with durvalumab as maintenance therapy for limited-stage SCLC (LS-SCLC). However, the high cost of durvalumab necessitates an evaluation of its cost-effectiveness.

A partitioned survival model was developed to assess the cost-effectiveness of durvalumab consolidation therapy compared with the standard of care (SOC). The model comprised three mutually exclusive health states: progression-free survival (PFS), progression of disease (POD)/metastasis, and death. Incremental cost-effectiveness ratio (ICER) was calculated as cost per quality-adjusted life year (QALY) gained, with a willingness-to-pay (WTP) threshold of $150,000 in US dollars (USD)/QALY. One-way and probabilistic sensitivity analyses were conducted. Analysis for POD was also stratified into intrathoracic, extrathoracic, and CNS.

Durvalumab improved overall survival (OS) to 66.1 months and PFS to 40.2 months, compared with 57.8 and 31.8 months for SOC, respectively. The total cost of durvalumab was $163,722 USD versus $25,816 USD for placebo, resulting in an incremental cost of $137,905 USD. Durvalumab provided an incremental QALY gain of 0.36 years, yielding an ICER of $383,069 USD/QALY, exceeding WTP. On stratification, durvalumab in patients with extrathoracic progression nearly met WTP (ICER, $151,137 USD).

Durvalumab remains cost-prohibitive for the overall cohort, exceeding acceptable thresholds despite favorable outcomes. Subgroup analysis, however, indicates that selective use in patients with extrathoracic progression may enhance cost-effectiveness. Overcoming economic barriers will be essential for the sustainable integration of immunotherapy into routine care.