Reduced Dose Ibrutinib Due to Financial Toxicity in CLL

Ibrutinib is the only approved novel agent that is available for the treatment of relapsed-refractory and treatment-naive chronic lymphocytic leukemia patients with deletion 17p or TP53 mutation in India. The cost of ibrutinib is still prohibitive for most Indian CLL patients. We report here for the first time dose reductions due to the patient preference of financial toxicity. We prospectively followed up patients of CLL receiving ibrutinib at a tertiary referral center in India. The period of study was from April 2016 to April 2018. Reduced dose ibrutinib was defined as a sustained (≥ 12 months) dosing at < 420 mg/day, either at treatment initiation or within 3 months from starting therapy. Progression free survival was compared using Kaplan-Meier analysis. There were a total of three patients on reduced dose and twelve patients on standard dose ibrutinib. Two patients discontinued standard dose ibrutinib due to adverse events. The patient age, cytogenetics, number of prior therapies and follow-up were not significantly different between the two groups. The rate of ≥ grade3 adverse events was significantly different between the two groups. The overall response rate and median PFS were also not significantly different between the two groups. In the limited patient numbers and follow-up period we show that outcomes of reduced dose ibrutinib are comparable to standard dose ibrutinib but with fewer adverse events. This study provides a proof of concept that a subset of patients might do well on reduced dose ibrutinib.