Carfilzomib-induced thrombotic microangiopathy is underestimated in clinical practice: A report of five patients and literature review.

Carfilzomib (Cfz) is widely used to treat multiple myeloma. However, real-world data of the incidence of thrombotic microangiopathy (TMA) caused by Cfz is inconsistent (<1-5%). We evaluated 96 consecutive patients who received Cfz to evaluate the incidence of TMA in clinical practice. TMA developed in five patients (5.2%) who were mainly receiving high-dose Cfz (≥56 mg/m 2 ). Based on a literature review, precaution should be taken for Cfz-induced TMA in male patients receiving high-dose Cfz irrespective of the combination therapy, Cfz administration period, and complement level. In conclusion, Cfz-induced TMA might be underestimated in clinical practice, and early intervention should be considered.