this agent is approved as second - line therapy after failure of available standard - of - care therapies in leiomyosarcomas . the most common grade 3/4 we describe a case of a 37-year - old male who was admitted to the vienna general hospital , medical university vienna , due to abdominal pain . magnetic resonance imaging showed a right - sided retroperitoneal tumor , infiltrating the right kidney , the right adrenal gland and the inferior caval vein . additionally , an abdominal computed tomography ( ct ) was performed , which showed further metastases in the lymph nodes and ascites . in february 2008 , the patient underwent debulking surgery of the tumor , resection of the right kidney and of the inferior caval vein with gore - tex replacement . histopathology revealed a marginally resected leiomyosarcoma g3 of 20  11  16.5 cm in size . immunohistochemical analysis showed tumor cells positive for vimentin , smooth muscle actin ( 1a4 ) and , to a lesser extent , for desmin . reactions with antibodies against cd117 ( c - kit ) , cd34 and p53 were negative . subsequent to progression , second - line therapy with doxorubicin 75 mg / m every 3 weeks was administered . due to progressive disease after 2 cycles , ifosfamide ( 1,500 mg / m , day 15 , every 21 days ) was given as third - line therapy with subsequent progression of disease after 3 cycles . thereafter , trabectedin ( 1.5 mg / m continous infusion over 24 h every 3 weeks ) was started . best overall response was stable disease ( sd ) , which lasted for 11 cycles . in the 8th cycle of trabectedin , creatinine kinase ( ck ) level levels of tnt , ck - mb , ldh were within normal values and the electrocardiogram showed no abnormalities . the patient complained of general muscle pain , but he did not report any previous excessive muscle training or trauma . a biopsy of the muscle cell , in order to verify suspected rhabdomyolysis , was refused by the patient . due to the limited availability of further therapeutic options and after careful consideration of risks related to continuation of trabectedin and the potential benefit of sd after 8 cycles of trabectedin , trabectedin was continued under the condition of extensive monitoring of the patient . all 3 cycles were dose reduced ( 1.2 mg / m ) due to elevated serum creatinine levels of 2.12 mg / dl ( normal value < 1.2 mg / dl ) . ck levels , which were still elevated ( = 1.5  uln ) after the 9th and 10th cycle dropped to 78 u / l , which is normal after the 11th cycle . the most recent creatinine level was 2.05 mg / dl , and the patient is doing well . he still has an ecog ps of 0 , and a recent ct scan showed sd . leiomyosarcomas are rare malignant tumors of smooth muscle differentiations that may arise in any organ or tissue that contains smooth muscle . leiomyosarcomas are most frequently found in the stomach and small intestine and may also be commonly found in the abdomen and retroperitoneum . however , besides the walls of the gastrointestinal tract , they normally arise in the walls of large vessels . trabectedin is a marine - derived antineoplastic compound isolated from the caribbean tunicate ecteinascidia turbinate and currently produced synthetically . the efficacy of trabectedin at a dose of 1.5 mg / m , given intravenously over 24 h every 3 weeks in patients with advanced soft tissue sarcomas was previously evaluated in 4 phase ii studies [ 5 , 6 , 7 , 8 ] . in a study by the french study group , the most common grade 3/4 toxicities were anemia , thrombocytopenia , and transient elevation of liver enzymes ( ast / alt ) . to the best of our knowledge , this is the first reported case of a continuation of trabectedin despite a severe trabectedin - related ck elevation . in this specific case , however , reported findings should not be interpreted as suggestion to continue treatment regardless of drug - related toxicity . they should rather serve as a description of specific findings related to a relatively new drug .
trabectedin has been reported to occasionally induce rhabdomyolysis . in the present case , 
 continuation of trabectedin was maintained despite suspected rhabdomyolysis related to trabectedin . 
 creatinine kinase levels dropped to normal levels . 
 we suggest that continuation of trabectedin despite suspected rhabdomyolysis was safe in this specific patient .