Tumour Lysis Syndrome and Partial Remission Occurring After Administration of a Test Dose of Obinutuzumab

Chronic lymphocytic leukaemia (CLL) is one of the most common haematological malignancies worldwide, with an increasing prevalence in the elderly population. Obinutuzumab is a type II anti-CD20 monoclonal antibody which showed superiority over rituximab in combination chemotherapy with chlorambucil for the treatment of CLL in the CLL11 trial (NCT01010061) and is becoming part of standard first line treatment for CLL in the elderly based on its potent efficacy and benign safety profile. We report the case of a chemotherapy naive patient who develop tumour lysis syndrome despite appropriate prophylaxis, and had partial remission of her disease after receiving only the initial test dose of obinutuzumab. LEARNING POINTS: Chemotherapy-induced tumour lysis syndrome is a serious complication that can occur after even a small dose of chemotherapy. Chronic lymphocytic leukaemia patients with strongly positive CD20 cells can be more sensitive to obinutuzumab chemotherapy.