OBJECTIVES

The study assessed the incremental cost-effectiveness of obinutuzumab plus chemotherapy (O-chemo) relative to rituximab plus chemotherapy (R-chemo) in patients with untreated advanced Follicular Lymphoma (FL), from the Italian Health Service (NHS) perspective.

METHODS

A four-state Markov model, adjusted to Italian setting, was used to estimate lifetime clinical outcomes and costs of patients with advanced FL in treatment with O-chemo and R-chemo. Life expectancy specific for therapeutic regimen derived from GALLIUM and PRIMA clinical trials: in particular, progression-free survival (PFS), early progressive disease (PD), and treatment duration (TTOT) were extrapolated by fitting parametric distributions on empirical data in GALLIUM, whilst late PD on data in PRIMA, due to immature data in GALLIUM. PD state was split in early (progression within 2-years) and late since patients progressing early have much poorer survival outcomes than those progressing later. Expected survival was weighted by published utilities. Unit costs were collected from official and published Italian sources. Costs, updated to 2018 Euro, and health gains occurring after the first year were discounted at an annual 3% rate. Sensitivity and scenario analyses were carried out, with the aim of evaluating uncertainty around model assumptions.

RESULTS

Obinutuzumab is associated with incremental survival (1.3 LYs), even when weighted for quality (1.1 QALYs), and incremental costs (€ 24,000), driven by longer treatment duration in the progression-free state relative to rituximab. Incremental ratios (around € 18,000 per LY and € 21,500 per QALY gained) are widely within the range considered acceptable by the Italian NHS. 1,000 PSA simulations confirm robustness of results to sensible variations in assumptions.

CONCLUSIONS

Obinutuzumab has a superior clinical efficacy, as compared to rituximab, and should be considered a cost-effective option in the first line treatment of advanced FL in Italy: incremental cost-effectiveness ratios are below the threshold considered sustainable by developed countries.