Carfilzomib-associated tumor lysis syndrome.

Multiple myeloma is the second most common type of hematologic malignancy. It is a B-cell malignancy that affects the bone marrow and often results in thrombocytopenia as well as renal dysfunction. Treatment options range from oral and intravenous chemotherapy to bone marrow transplantation and supportive care. Carfilzomib was approved by the U.S. Food and Drug Administration in 2012 as a treatment option for patients with refractory multiple myeloma who have received at least two previous therapies and have demonstrated recent disease progression. According to the product labeling, the frequency of tumor lysis syndrome (TLS) is less than 1% in patients treated with carfilzomib. To our knowledge, no postmarketing events of TLS have been reported or published. We describe a 55-year-old man with relapsed multiple myeloma who developed a case of TLS that occurred after he received his first two doses of carfilzomib therapy on days 1 and 2; he also had chronic kidney disease secondary to his neoplastic disease. Beginning on day 4, his uric acid levels spiked to critical levels, prompting the use of rasburicase, which returned the levels to within normal limits. His phosphorus and creatinine levels increased during days 5 and 6. On day 8, the patient died, likely due to a combination of disease progression and the adverse effects of treatment. Use of the Naranjo adverse drug reaction probability scale indicated a probable relationship (score of 6) between the patient's development of TLS and carfilzomib therapy. The Hill criteria were used as a secondary measure to ensure causality, which also suggested a link between the patient's development of TLS and the administration of carfilzomib. This case report shows that even the most unlikely of adverse events may occur with medications, especially in the case of a new or recently approved medication. Caution must be taken when deciding to treat and when choosing hydration and premedications with regard to biologic and chemotherapeutic medications. In this case, additional hydration may have been considered. Although given the extent of the adverse reaction combined with the patient's underlying renal dysfunction, extra fluid may or may not have proven beneficial. The use of prophylactic rasburicase or allopurinol could have been considered, but these measures are not typically used with multiple myeloma due to the low incidence of TLS. All things considered, this unlikely adverse reaction may occur in certain patients. If other cases such as this occur, it may be advisable to use TLS prophylaxis in the future in certain patient populations, including those with renal dysfunction or worsening disease states.