OBJECTIVES: To evaluate the cost-effectiveness of ofatumumab plus chlorambucil (OChl) versus chlorambucil (Chl) for the first-line treatment of chronic lymphocytic leukemia (CLL) in patients not eligible for fludarabine-based therapy from the United Kingdom health care payer perspective.

METHODS: A semi-Markov decision model was developed with a lifetime time horizon of 25 years and a 3-month cycle length. The COMPLEMENT-1 trial provided estimates of overall response rates (ORR), progression-free survival (PFS), overall survival (OS), safety data, and preprogression utility weights (EQ-5D). The number of patients in the “preprogression,” “progressive disease,” and “dead” health states at the end of each cycle was determined by parametric survival functions for PFS and OS. Long-term predictions for OS were guided by external data; the treatment effect observed in the trial was assumed not to continue beyond trial follow-up. Data from published literature and UK treatment practices and patterns were used to inform costs and utility in the postprogression health states. Incremental lifetime costs and quality-adjusted life-years (QALYs) were calculated.

RESULTS: The base-case incremental cost-effectiveness ratio (ICER) was £31,827 per LY gained, with incremental discounted costs and LYs of £10,492 and 0.33, respectively. Discount rate was 3.5% for both cost and outcomes. Univariate sensitivity analyses indicated that the proportion of patients who received active therapy after progression following first-line treatment (responders, active second-line treatment) had the largest influence on the ICER. However, none of the variables considered generated an ICER exceeding £38,000 per QALY gained.

CONCLUSIONS: The improved ORR, PFS, and OS for OChl compared with Chl translated to improved long-term health outcomes in the base-case analysis. The results were robust in a wide range of sensitivity analyses and did not exceed £38.000/QALY.