OBJECTIVES : Small cell lung cancer (SCLC) treatment had remained largely unchanged for 20-30 years. In 2019, Tecentriq (atezolizumab) in combination with carboplatin+etoposide was the first cancer immune therapy approved for 1L ES-SCLC. Recently, durvalumab with carboplatin+etoposide has shown significantly improved survival over carboplatin+etoposide alone for ES-SCLC. Our analysis examines cost differences between atezolizumab- or durvalumab-based regimens in 1L ES-SCLC, to inform assessment of economic value.

METHODS : Cost of therapy was calculated according to label- or trial-based dosing. Treatment duration was based on median progression-free survival (mPFS), assuming treatment-to-progression in base case. The atezolizumab cost reflected 1200mg Q3W dosing over a duration of 5.2 months (from IMpower133 trial). The durvalumab cost reflected CASPIAN trial dosing: 1500mg Q3W dosing over 5.1 months. Carboplatin+etoposide dosing was assumed equivalent between regimens: four cycles with AUC5 carboplatin and 100mg/m² etoposide (average patient body surface area of 1.81m²; IMpower133). No vial sharing was assumed. Drug unit costs reflect Jan 2020 wholesale acquisition costs (WAC) and average sales price (ASP) in alternate scenarios. Infusion administration costs were based on the most recent (2019) CMS Physician Fee Schedule ($143.08/first drug; $69.20/additional drug). Sensitivity analyses explored equivalent 24-week duration. The analyses do not account for discounts or rebates, which are not publicly available information, and could affect net cost to payers.

RESULTS : Total base case drug+administration costs: atezolizumab-combination WAC $70,857, ASP $67,926; durvalumab-combination WAC $73,721, ASP $71,679. Over 24 weeks, atezolizumab-combination costs were WAC $75,525, ASP $72,405, and durvalumab-combination costs were WAC $78,795, ASP $76,617, of which administration costs accounted for $1698 and $1555, respectively.

CONCLUSIONS : This analysis suggests that the median cost for a durvalumab-based regimen may be 4.0-5.8% higher than an atezolizumab-based regimen for 1L ES-SCLC, using WAC or ASP. Additional research is required to characterize real-world utilization and outcomes, which may impact total costs from a payer perspective.