IMBRUVICA® (ibrutinib) Is an Oral, Once-Daily CLL/SLL Medicine That Works Differently Than Chemotherapy1
- Bruton’s tyrosine kinase (BTK) is a protein found in your B cells. It sends “signals” that help B cells stay alive and multiply
- IMBRUVICA® blocks BTK signaling. This helps stop B cells from surviving and multiplying
- IMBRUVICA® may slow the spread of CLL or SLL
- Bruton's tyrosine kinase (BTK) is a protein involved in the development of mature B cells.2
Because of how IMBRUVICA® works, it may cause side effects. A relationship between how IMBRUVICA® works and why it helps to treat CLL has not been clearly identified.
You may experience changes in your white blood cell count1,3
After starting IMBRUVICA®, your doctor will perform blood tests to measure the kind and number of cells in your blood. Your lab results may show an increase in lymphocytes, a type of white blood cell. This is called lymphocytosis and can occur with IMBRUVICA® treatment. In the absence of other signs and symptoms, this increase may not necessarily mean your condition is worsening.
In 3 IMBRUVICA® clinical trials, about 2 out of 3 (66%) people with CLL/SLL taking IMBRUVICA® developed lymphocytosis. This usually happened during the first month that people started taking IMBRUVICA®. How long lymphocytosis lasted varied. It went away by a median* of 14 weeks (range of less than 1 day to 26 months).
*Median is the middle number in a group of numbers that are arranged from lowest to highest. For example, in the group of numbers 1-11, 6 is the median.
References: 1. IMBRUVICA® (ibrutinib) Prescribing Information. 2. National Institutes of Health. Isolated growth hormone deficiency. Accessed August 23, 2022. https://medlineplus.gov/genetics/condition/isolated-growth-hormone-deficiency/ 3. Hallek M, Cheson BD, Catovsky D, et al. iwCLL guidelines for diagnosis, indications for treatment, response assessment, and supportive management of CLL. Blood. 2018;131(25):2745-2760.