A Rare Side Effect of Ibrutinib: Tumor Lysis Syndrome.

Chronic lymphocytic leukemia (CLL) is a progressive disease with an indolent course, and tumor lysis syndrome (TLS) is rarely seen in CLL. Ibrutinib is a novel bruton kinase (BTK) inhibitor increasingly used in CLL treatment. Ibrutinib has significant side effects such as atrial fibrillation, bleeding, diarrhea, and infections. However, TLS is reported rarely with ibrutinib treatment. This report focuses on a 69-year-old female patient diagnosed with relapsed CLL who developed grade 4 TLS after ibrutinib monotherapy. The patient developed TLS on the third day of ibrutinib treatment necessitating discontinuation of the treatment and initiation of hemodialysis and supportive care. Ibrutinib treatment was re-initiated at a daily dose of 140 mg therapy after an interval of seven days, and then any additional side effect was not seen. Tumor lysis syndrome secondary to ibrutinib has been reported in an increasing number of cases. There is currently no information on managing adverse effects of TLS attributed to ibrutinib. Consequently, ibrutinib treatment of this patient was not terminated, and restarted after a short interval. It must not be forgotten that TLS secondary to ibrutinib treatment may be rarely seen, and can be life-threatening. Treatment with ibrutinib should be initiated in consideration of this side effect, and the development of complication of TLS may not necessitate discontinuation of ibrutinib treatment.