Bortezomib-induced pneumonitis during bortezomib retreatment in multiple myeloma

Bortezomib is a proteasome inhibitor and is active against multiple myeloma. Most toxicities associated with bortezomib are mild to moderate and manageable; however, bortezomib-induced pneumonitis has been reported in some multiple myeloma cases. Bortezomib-induced pneumonitis was reported to occur relatively soon after the first administration of bortezomib. A 64-year-old Japanese man with multiple myeloma received low-dose dexamethasone followed by bortezomib monotherapy as the initial therapy. He had no pulmonary complications during bortezomib treatment. Thereafter, he was treated with high-dose chemotherapy, followed by autologous peripheral blood stem cell transplantation. Ten months after autologous peripheral blood stem cell transplantation, his disease relapsed and he received bortezomib retreatment. On the fifth day after the second dose of weekly bortezomib, he complained of mild dyspnea, dry cough and fever. High-resolution computed tomography of the chest showed bilateral infiltrates with partial ground glass appearance in the lower lobes. The diagnosis of bortezomib-induced pneumonitis was made. His bortezomib-induced pneumonitis responded to steroid therapy and his respiratory symptoms disappeared. This is the first report in which bortezomib-induced pneumonitis occurred during bortezomib retreatment for relapsed multiple myeloma. Careful management is needed during bortezomib retreatment, even after the previous course of bortezomib was administered safely.