Abstract
Ibrutinib is a novel oral therapy that has shown significant efficacy as initial treatment of chronic lymphocytic leukemia (CLL). It is a high-cost continuous therapy differing from other regimens that are given for much shorter courses. Our objective was to evaluate the cost-effectiveness of ibrutinib for first-line treatment of CLL in patients older than age 65 years without a 17p deletion. We developed a semi-Markov model to analyze the cost-effectiveness of ibrutinib vs a comparator therapy from a US Medicare perspective. No direct comparison between ibrutinib and the best available treatment alternative, obinutuzumab plus chlorambucil (chemoimmunotherapy), exists. Therefore, we compared ibrutinib to a theoretical treatment alternative, which was modeled to confer the effectiveness of an inferior treatment (chlorambucil alone) and the costs and adverse events of chemoimmunotherapy, which would provide ibrutinib with the best chance of being cost-effective. Even so, the incremental cost-effectiveness ratio of ibrutinib vs the modeled comparator was $189 000 per quality-adjusted life-year (QALY) gained. To reach a willingness-to-pay threshold (WTP) of $150 000 per QALY, the monthly cost of ibrutinib would have to be at most $6800, $1700 less than the modeled cost of $8500 per month (a reduction of $20 400 per year). When the comparator efficacy is increased to more closely match that seen in trials evaluating chemoimmunotherapy, ibrutinib costs more than $262 000 per QALY gained, and the monthly cost of ibrutinib would need to be lowered to less than $5000 per month to be cost-effective. Ibrutinib is not cost-effective as initial therapy at a WTP threshold of $150 000 per QALY gained.