OBJECTIVES: In September 2020, Selpercatinib, conditionally approved for treating RET-fusion positive non-small cell lung cancer (NSCLC), was rejected for reimbursement in Norway, citing limited evidence from the Phase II single-arm LIBRETTO-001 trial. Combining single-arm trial (SAT) data with structured expert elicitation (SEE) may help inform the standard-of-care outcomes. We explored the contribution of SEE to support a cost-effectiveness analysis of Selpercatinib at Phase II compared with waiting for the Phase III randomized controlled trial (RCT).

METHODS: We developed a probabilistic three-state partitioned survival model to compare health and economic outcomes of Selpercatinib versus standard-of-care between ‘Phase II’ and ‘Phase III’ analyses. For the Phase II analysis, we extrapolated progression-free survival (PFS) and overall survival (OS) for the treatment arm from the LIBRETTO-001 trial, and used aggregated SEE data for the standard-of-care arm. SEE involved eliciting survival distributions at three time points from three clinical-oncologists. For the Phase III analysis, PFS and OS for both arms were derived from the LIBRETTO-431 trial, adjusting the standard-of-care arm costs for treatment switching. Outcomes included discounted (4%/year) incremental costs, quality-adjusted life years (QALYs), and incremental cost-effectiveness ratios (ICERs) from an extended healthcare perspective. ICERs were compared to the maximum severity-specific threshold of €73,000/QALY gained.

RESULTS: The Phase II analysis, involving SEE, found Selpercatinib provided an additional 1.42 QALYs, required an additional €8,592 per person, and yielded an ICER of €12,458/QALY gained. The Phase III analysis projected higher incremental QALYs (2.15 QALYs) and higher incremental costs (€11,826), yielding an ICER of €30,346/QALY gained. Given the Norwegian severity-specific threshold, both analyses identified Selpercatinib as potentially cost-effective.

CONCLUSIONS: Using SEE in Phase II SAT yielded comparable decisions to Phase III RCT for Selpercatinib in NSCLC. Further research should explore SEE's applicability and potential role in study design for collecting additional information (value of information).