[Carfilzomib-induced renal impairment with albuminuria in a patient with relapsed/refractory multiple myeloma].

A 70-year-old woman was diagnosed with multiple myeloma in 2014. She achieved complete remission (CR) after bortezomib, cyclophosphamide, dexamethasone (VCD) therapy and lenalidomide, dexamethasone (Rd) therapy; however, she relapsed in 2017. Although she achieved second CR by carfilzomib, dexamethasone (Kd) therapy, serum creatinine levels increased with urinary protein after 17 courses of Kd therapy. Urinary protein test revealed albuminuria, whereas M-protein was undetectable. Carfilzomib-induced renal impairment was suspected due to absence of other causes, such as progression of myeloma or autoimmune disease. On discontinuation of Kd therapy, urinary protein decreased rapidly with improvement of serum creatinine levels within a month. Carfilzomib-induced nephrotoxicity is a rare but important adverse event.