Objective @entity5 responses and survival rates with standard chemotherapy options for @entity151 ( @entity151 ) and @entity1149 ( @entity1149 ) have been disappointing. However, several promising new classes of agents have emerged in recent years, including the @entity6023 , mitotic spindle inhibitors, antimetabolites, and topoisomerase I and II inhibitors. The molecular target of several of these new agents is topoisomerase I, an enzyme that is essential for DNA replication and is up-regulated in @entity5 cells. Inhibition of this enzyme by drugs such as @entity1945 and irinotecan leads to cell death and is the basis for their anticancer activity. The process of DNA replication is halted by the covalent binding of the drug in a topoisomerase I drug/DNA ternary reaction intermediate. The pharmacokinetics of the approved regimen--a 30-min infusion daily for 5 days at 21-day intervals--are well defined, with proportional increases in the area under the plasma concentration-time curve, peak plasma concentration, and steady state concentration following application of higher doses. The antitumor activities of both the intravenous and oral formulations of @entity1945 have been tested in clinical trials. @entity1945 is well tolerated and has demonstrated good efficacy in @entity1 with relapsed @entity151 when administered as monotherapy or in combination regimens as first-line or second-line therapy. Preliminary trials also indicate that @entity1945 is well tolerated and has activity in the first-line treatment of @entity1149 . In this article an overview of new agents in @entity2 chemotherapy is provided, with particular attention paid to the topoisomerase I inhibitors. A review of @entity1945 --the first topoisomerase I inhibitor to be approved for second-line therapy in @entity151 --is presented as an illustration of the promise these new agents hold for the treatment of @entity151 and @entity1149 .

New advances in XXXX chemotherapy: @entity1945 and the role of topoisomerase I inhibitors.

@entity1 :: ('9606', 'Species') :: ['patients'] @entity6023 :: ('MESH:D043823', 'Chemical') :: ['taxanes'] @entity5 :: ('MESH:D009369', 'Disease') :: ['tumor'] @entity1149 :: ('MESH:D002289', 'Disease') :: ['NSCLC', 'non-small-cell lung cancer'] @entity2 :: ('MESH:D008175', 'Disease') :: ['lung cancer'] @entity151 :: ('MESH:D055752', 'Disease') :: ['SCLC', 'small-cell lung cancer'] @entity1945 :: ('MESH:D019772', 'Chemical') :: ['Topotecan', 'topotecan']
@entity2 :: (MESH:D008175,Disease) :: ['lung cancer']
