Ibrutinib, a widely used Bruton tyrosine kinase inhibitor, is extensively used in the treatment of lymphocytic malignancies, including chronic lymphocytic leukemia (CLL).1,2 Respiratory complications associated with the use of ibrutinib include cough (13–22%), dyspnea (10–12%), oropharyngeal pain (14%), pneumonia (12–23%), sinusitis (11–22%), upper respiratory tract infection (16–47%), pneumonitis, and interstitial lung disease.3 The gene discussed is BTK; the disease is B-cell chronic lymphocytic leukemia.