Cost-Effectiveness of Ibrutinib Compared With Obinutuzumab With Chlorambucil in Untreated Chronic Lymphocytic Leukemia Patients With Comorbidities in the United Kingdom.

Background: Ibrutinib shows superiority over obinutuzumab with chlorambucil (G-Clb) in untreated patients with chronic lymphocytic leukemia with comorbidities who cannot tolerate fludarabine-based therapy. However, ibrutinib is relatively more expensive than G-Clb. In this study we evaluated the cost-effectiveness of ibrutinib compared with G-Clb from the United Kingdom (UK) health care perspective.

Materials And Methods: A 3-state semi-Markov model was parameterized to estimate the lifetime costs and benefits associated with ibrutinib compared with G-Clb as first-line treatment. Idelalisib with rituximab was considered as second-line treatment. Unit costs were derived from standard sources, (dis)utilities from UK elicitation studies, progression-free survival, progression, and death from clinical trials, and postprogression survival and background mortality from published sources. Additional analyses included threshold analyses with ibrutinib and idelalisib at various discount rates, and scenario analysis with ibrutinib as second-line treatment after G-Clb.

Results: An average gain of 1.49 quality-adjusted life-years (QALYs) was estimated for ibrutinib compared with G-Clb at an average additional cost of £112,835 per patient. To be cost-effective as per the UK thresholds, ibrutinib needs to be discounted at 30%, 40%, and 50% if idelalisib is discounted at 0%, 25%, and 50% respectively. The incremental cost-effectiveness ratio was £75,648 and £-143,279 per QALY gained for the base-case and scenario analyses, respectively. Sensitivity analyses showed the robustness of the results.

Conclusion: As per base-case analyses, an adequate discount on ibrutinib is required to make it cost-effective as per the UK thresholds. The scenario analysis substantiates ibrutinib's cost-savings for the UK National Health Services and advocates patient's access to ibrutinib in the UK.