Estimated Cost-effectiveness of Atezolizumab Plus Cobimetinib and Vemurafenib for Treatment of BRAF V600 Variation Metastatic Melanoma.

Importance: In the IMspire150 trial, triplet treatment with atezolizumab and vemurafenib plus cobimetinib significantly improved progression-free survival (PFS) compared with vemurafenib plus cobimetinib alone for treatment of BRAF V600 variation metastatic melanoma. However, considering high cost of this combination, it is unclear if the incremental cost is worth the additional survival benefit. Objective: To evaluate the cost-effectiveness of atezolizumab and vemurafenib plus cobimetinib vs vemurafenib plus cobimetinib alone in patients with newly diagnosed unresectable BRAF V600 variation metastatic melanoma from the US health care perspective. Design, Setting, and Participants: This economic evaluation study used a 3-state partitioned survival model to assess the cost-effectiveness of the combination of atezolizumab with vemurafenib plus cobimetinib vs vemurafenib plus cobimetinib alone. The observed Kaplan-Meier curves for overall survival and PFS were digitized from the IMspire150 trial (January 2017-April 2018) and the long-term survivals (over a lifetime horizon) beyond the end of the trial were extrapolated using 7 different survival models. The cost and health preference data were collected from a literature review. This study was performed from March 2021 through June 2021. Main Outcomes and Measures: The outcomes of interest were expected life-years (LYs) gained and quality-adjusted life-years (QALYs), costs, and incremental cost-effectiveness ratio (ICER), expressed as cost per LYs and per QALYs saved. Results: Adding atezolizumab to vemurafenib and cobimetinib provided an additional 3.267 QALYs compared with the doublet regimen of vemurafenib plus cobimetinib, at an ICER of $271 669 per QALY, which is not considered cost-effective at the willingness-to-pay threshold of $150 000 per QALY. However, the scenario analyses found that atezolizumab combined with vemurafenib plus cobimetinib could be cost-effective at 20-year (ICER, $121 432 per QALY) and 30-year ($98 092 per QALY) time horizons when both strategies were stopped after 2 years of treatments, and over a lifetime horizon ($122 220 per QALY) when only immunotherapy with atezolizumab was stopped after 2 years of treatment. Conclusions and Relevance: These findings suggest that the atezolizumab and vemurafenib plus cobimetinib regimen provides significant survival benefits over vemurafenib plus cobimetinib alone, and a price reduction would be encouraged to maximize the value of its survival gain.