Severe pneumonia associated with ibrutinib monotherapy for CLL and lymphoma

In recent years, there have been major advances in the treatment of chronic lymphocytic leukemia (CLL) particularly since the development of novel therapeutic agents, mostly "biological drugs." One of the obvious advantages of these agents is the decreased rate of infectious complications occurring during the course of therapy, compared to the use of standard immuno-chemotherapy regimens. Here, we describe 3 patients with CLL and 1 with mantle cell lymphoma who developed severe life-threatening pneumonias, during monotherapy with ibrutinib. The first case was a 70-year-old woman with relapsed CLL who developed bilateral pneumonia with hypoxia 1 week after starting ibrutinib. She did not respond to broad-spectrum antibiotics and was treated empirically with trimethoprim-sulphamethoxazole and improved. In the second case, we describe a 76-year-old woman with relapsed CLL who developed recurrent pneumonia after 3 years of treatment with ibrutinib. Presuming that ibrutinib was the cause of pneumonitis with secondary infection, it was stopped with subsequent improvement. The third patient a 67 year-old man died because of severe bilateral necrotizing pneumonia due to invasive aspergillosis and mucormycosis with pulmonary hemorrhage. The fourth patient with relapsed mantle cell lymphoma died because of severe bilateral pneumonia, caused by pseudomonas and candida, despite receiving appropriate antibiotics. From this experience, we hypothesize that the etiology of severe pneumonia associated with ibrutinib treatment is probably multifactorial, involving factors like preexisting immune-suppression, drug induced pneumonitis and infections. We suggest that patients with CLL or other lymphoproliferative disorders with suspected pneumonia during monotherapy with ibrutinib should be very carefully evaluated and need to undergo complete diagnostic workup to establish an exact diagnosis. Understanding which patients with CLL or lymphoma treated with kinase inhibitors are at a higher risk for developing pulmonary complications could be one of the important future challenges, when selecting the best available therapy for these patients.