Future directions for clinical research with CPT-11 (irinotecan).
CPT-11 is a new agent with a unique mechanism of action, namely the inhibition of topoisomerase I. An examination of data from the laboratory reveals several leads which should be pursued in the clinic. A dose-response effect for CPT-11 activity has been noted in the human tumour cloning assay. CPT-11 has activity against breast and mesothelioma colony-forming units in a human tumour cloning assay, and has in vivo activity against a number of paediatric malignancies. Promising combinations in preclinical in vivo models include CPT-11/mitomycin C and CPT-11/cytosine arabinoside. There is incomplete cross-resistance among topoisomerase I inhibitors, suggesting that combinations of topoisomerase I inhibitors should be investigated. Several natural products have been identified which have potential to decrease CPT-11-induced diarrhoea. The level of carboxylesterase in a patient's tumour appears to be related to the in vitro activity of CPT-11, suggesting that measurement of carboxylesterase in a patient's tumour could be used to identify patients who are most likely to respond to treatment with CPT-11. These preclinical findings suggest substantial further clinical potential for CPT-11 in terms of decreased CPT-11-induced diarrhoea as well as increased antitumour activity, which should be explored in phase I and II studies.
von Hoff
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Institute for Drug Development, Texas Research Park, San Antonio 78245, USA.
D000972:Antineoplastic Agents, Phytogenic / Q000627:therapeutic use*; D002166:Camptothecin / Q000031:analogs & derivatives* / Q000627:therapeutic use; D017321:Clinical Trials, Phase I as Topic; D017322:Clinical Trials, Phase II as Topic; D005260:Female; D006801:Humans; D000077146:Irinotecan; D012106:Research / Q000639:trends; D059004:Topoisomerase I Inhibitors
D000972:Antineoplastic Agents, Phytogenic; D059004:Topoisomerase I Inhibitors; D000077146:Irinotecan; D002166:Camptothecin