Immune modulation therapy in the management of bortezomib-induced peripheral neuropathy

Bortezomib is a reversible proteasome inhibitor, and has been approved by the FDA for the treatment of multiple myeloma either in combination with other agents or as a single agent [1,2]. One of the common side effects associated with bortezomib therapy is PN [3-7]. The neuropathy may be caused by direct toxic effect of bortezomib or through an immunologically mediated process [3-7]. Here, we reported our experience in managing a severe bortezomib-related PN with immune modulation treatment.This patient is a 65？years old Caucasian male who was diagnosed with multiple myeloma in December 2010 based on an IgG kappa paraprotein (3？g/dl), 25% kappa light chain restricted- plasma cells in bone marrow biopsy, and the presence of anemia (hemoglobin 9？g/dl). His past medical history was significant for type II diabetes mellitus well controlled with Metformin and Sitagliptin. On December 30, 2010, he was started on therapy with single agent bortezomib given at 1.3？mg/m2 intravenously weekly. Dexamethasone was not given due to concern for hyperglycemia with his underlying diabetes. On January 20, 2011, lenalidomide was added at 10？mg a day two weeks on and one week off schedule. On February 15, 2011, during approximately the third cycle of bortezomib treatment, the patient started having severe pain in both legs extending from his thighs to his calves that he described as “toothache-like” pain as well as some mild paresthesias and muscle spasms. His chemotherapy was stopped on March 8, 2011. He also developed progressively worsening bilateral lower extremity weakness. Within one week, the patient was unable to walk. He could not move his legs and required the assistance of a wheelchair for mobility.On physical examination: the cranial nerves were normal and extraocular muscles were intact. Manual motor test was performed and showed: Deltoid, biceps, triceps, and wrist extensor 5/5, finger extensor 4/5 bilaterally, first dorsal interosseous 3+/5 bilaterally, abductor digiti mi