Cost-utility analysis of idelalisib in combination with rituximab in relapsed or refractory chronic lymphocytic leukaemia.

Objective: To evaluate the incremental cost-utility ratio (ICUR) of idelalisib in combination with rituximab (IR) versus rituximab monotherapy (R) in the treatment of patients with relapsed or refractory (R/R) chronic lymphocytic leukaemia (CLL), from the Spanish National Health System (NHS) perspective.

Methods: A partitioned survival Markov model for a lifetime horizon (30 years) was developed to estimate costs (€, 2016) and quality-adjusted life years (QALY) with IR and R. Initial cohort included patients with CLL receiving a second or subsequent line (2L) of treatment with IR or R. Survival data were based on CLL clinical trial. Drug, administration, monitoring, adverse events and clinical management of CLL costs were included in the model. Costs and outcomes were discounted using a 3% annually. Deterministic and probabilistic sensitivity analyses (PSA) were performed.

Results: Compared to R, 2L IR treatment resulted in QALY gain of 3.147 (4.965 versus 1.818). Total costs were €118 254 for IR versus €23 874 for R. ICUR was €29 990/QALY gained with IR versus R. In the PSA, IR was cost-effective in 78% of iterations using a threshold of €45 000/QALY.

Conclusion: IR can be considered a cost-effective treatment compared to R, in the treatment of R/R CLL patients for the Spanish NHS.