Obinutuzumab Plus Chemotherapy Compared with Rituximab Plus Chemotherapy in Previously Untreated Italian Patients with Advanced Follicular Lymphoma at Intermediate-High Risk: A Cost-Effectiveness Analysis

Objective: To assess the cost-effectiveness of obinutuzumab (O-chemo) in comparison to rituximab (R-chemo) in patients with untreated advanced follicular lymphoma (FL) at intermediate or high risk from an Italian National Health Service (NHS) perspective. Methods: A previously developed four-state Markov model was adapted to estimate lifetime clinical outcomes and costs of Italian patients with advanced FL and an FL international predictive index score >= 2 in treatment with O-chemo and R-chemo. Life expectancy was derived from the GALLIUM and PRIMA clinical trials. Progression-free survival (PFS), early progressive disease (PD), and treatment duration were extrapolated by fitting parametric distributions to empirical data in GALLIUM and late PD to data in PRIMA. Expected survival was weighed by published utilities. Costs updated to 2020 Euros and health gains occurring after the first year were discounted at an annual 3% rate. Probabilistic sensitivity analysis (PSA) was carried out. Results: O-chemo was associated with an incremental survival increase (0.97 life-years [LYs]), even when weighted for quality (0.88 quality-adjusted LYs [QALYs]), and incremental costs (around (sic)15,000), driven by longer treatment during PFS state relative to R-chemo. The incremental cost-effectiveness ratio and incremental cost-utility ratio are both widely accepted by the Italian NHS (around (sic)15,500/LY and (sic)17,000/QALY gained, respectively). PSA simulations confirmed the robustness of results given sensible variations in assumptions. Conclusion: O-chemo has superior clinical efficacy compared to rituximab, and should be considered a cost-effective option in first-line treatment of patients with advanced FL at intermediate or high risk in Italy. Incremental cost-effectiveness ratios are below the threshold considered affordable by developed countries.