After discontinuing ibrutinib, roughly 25% of patients diagnosed with chronic lymphocytic leukemia (CLL) suffer from a flare of the illness. Whether or not this incident would also ensue when ibrutinib is briefly held off is an important question. Determining the frequency and attributes of disease flares in such a setting and evaluating the risk factors and clinical results were the main objectives of this study.

In the time frame from October 2012 to March 2019, we recognized all the patients diagnosed with CLL at Mayo Clinic who received ibrutinib. Brief breaks in treatment and related clinical discoveries were ascertained.

At least one brief interruption (range 1-7 holds, median 1 hold) in treatment was found in 143 (38%) out of the 372 patients identified. 8 days (range 1-59 days) was the median duration of the break and periprocedural was the most widely recognized indication. 35 (25%) out of the 143 patients were found to have experienced a related disease flare: 21 patients had a mild flare (constitutional symptoms only) and 14 patients had a severe flare (constitutional symptoms with exam/radiographic findings or laboratory changes). In order to solve the disease flare, treatment through ibrutinib was resumed in all of the patients. Growing disease at the time of holding off ibrutinib, as well as greater than or equal to 24 months of ibrutinib exposure, were the predictive factors of disease flare. A shorter event-free survival (hazard ratio 2.3; 95% CI 1.3–4.1; p=0.007) was related to the occurrence of a flare of the disease whilst holding off ibrutinib, but not with overall survival.

It is common for patients diagnosed with CLL to have brief breaks in ibrutinib treatment. A flare in disease in patients who held off ibrutinib was seen in one-quarter of the patients in a study. Resolving this issue by resuming ibrutinib emphasizes the significance of awareness of this event for optimal management.