Hira Shaikh, Ahmed Khattab, Muhammad S Faisal, Abhishek Chilkulwar, Mary Albrethsen, Santhosh Sadashiv, Salman Fazal

Background Ibrutinib, a Bruton's tyrosine kinase inhibitor has reformed the treatment of various B-cell malignancies including chronic lymphocytic leukemia, mantle cell lymphoma, and Waldenstrom's macroglobulinemia. Although generally well tolerated, here we describe our institutional experience of unique adverse effects encountered with the use of ibrutinib in patients with B-cell lymphomas. Methods This is a retrospective observational study done at a tertiary care facility, to evaluate adverse events in patients with B-cell malignancies on treatment with ibrutinib between 2014 and 2018. Further details including type of malignancy, cytogenetics, interventions for treatment of the side effect, and outcomes were obtained through electronic health record. Case series We found 10 patients with unique adverse events related to ibrutinib. Among those, six had chronic lymphocytic leukemia, two had Waldenstrom's macroglobulinemia, and two had mantle cell lymphoma. The events included palindromic rheumatoid arthritis, diffuse spongiotic dermatitis, bullous pemphigoid, recurrent hemorrhagic stroke, peripheral neuropathy, recurrent paronychia, intramedullary fibrosis, recurrent joint pains, pulmonary aspergillosis, dyspnea with exacerbation of atrial fibrillation, and resolution of autoimmune hemolytic anemia. Conclusion Our case series illustrates the wide variety of unique events recognized in patients treated with ibrutinib, some of which required cessation and most had dose reduction of the treatment. Thus, stressing the importance of early identification and intervention for the events to avoid worsening of toxicity and inability to continue treatment in such patients.