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Medline ® Abstract for Reference 132

of 'Enterotoxicity of chemotherapeutic agents'

Severe CPT-11 toxicity in patients with Gilbert's syndrome: two case reports.
Wasserman E, Myara A, Lokiec F, Goldwasser F, Trivin F, Mahjoubi M, Misset JL, Cvitkovic E
Ann Oncol. 1997;8(10):1049.
BACKGROUND: CPT-11 is hydrolyzed to its active metabolite SN-38, which is mainly eliminated through conjugation by hepatic uridine diphosphate glucuronosyl transferases (UGTs) to the glucuronide (SN-38G) derivative. Preclinical studies showed that UGT*1.1 is the isozyme responsible for SN-38 glucuronidation. Patients with Gilbert's syndrome have deficient UGT*1.1 activity, therefore may have an increased risk for related CPT-11 toxicity.
PATIENTS AND METHODS: Two patients with metastatic colon cancer and Gilbert's syndrome were treated with CPT-11 based chemotherapy. CPT-11, SN-38 and SN-38G pharmacokinetics parameters were obtained. Serum bilirubin was analysed by alkaline methanolysis and HPLC.
RESULTS: Both patients presented grade 4 neutropenia and/or diarrhea (NCI-CTC) in every treatment cycle. Biliary index (after Gupta et al) values were well above 4000.
CONCLUSION: We present the first clinical evidence linking bilirubin glucuronidation status and CPT-11 related toxicity. The severe toxicity experienced by the two patients with Gilbert's syndrome treated with CPT-11 based chemotherapy has a genetic basis. Individuals with Gilbert's syndrome have an enhanced risk for CPT-11 toxicity. Unconjugated serum bilirubin could be predictive parameter of CPT-11 toxicity.
FSMSIT, Hop Paul Brousse, Villejuif, France.