Sinusoidal Obstruction Syndrome (SOS) in MultipleMyeloma with Renal Failure

SOS is a rare complication of stem cell transplantation and has significant morbidity and mortality. We present three cases of SOSand highlight underlying risk factors for its development, such as impaired clearance of alkylating agents (especially melphalan) inpatients with renal failure and prolonged infection. Although, melphalan and cyclophosphamide cause SOS less commonly thanalkylating agents such as busulfan, physicians must use caution when administering these drugs to patients with underlyingcomorbidities such as renal failure that may increase the likelihood of development of SOS. This is due to unpredictablepharmacokinetics in patients with renal failure and therefore close drug monitoring is required. With the recent FDA approvalof defibrotide in 2016, outcomes of SOS have improved and physician awareness is important for prompt diagnosis and treatment.