The effective and toxic ranges of anticancer drugs are very narrow and, in some cases, inverted. Thus determination of the most appropriate dosage and schedule of administration is crucial for optimal chemotherapy. In common arm trials conducted in Japan and by Southwest Oncology Group (SWOG) that used the same doses and schedules for the administration of carboplatin plus paclitaxel, the frequency of hematological toxicity was significantly higher in the Japanese trials than in the SWOG trial, despite demonstrating similar response rates. The frequency of epidermal growth factor receptor (EGFR) mutations in tumors was significantly higher among East Asian populations, and these populations are also reported to demonstrate a higher response rates to epidermal growth factor receptor tyrosine-kinase inhibitors (EGFR-TKIs). The prevalence of interstitial lung disease induced by treatment with EGFR-TKIs has been shown to be quite high in the Japanese population. Clinical trials of cetuximab against non-small cell lung cancer and of bevacizumab against stomach cancer have shown that these agents are only active in Caucasians. In a trial examining the use of sorafenib after transarterial chemoembolization in Korean and Japanese patients with advanced hepatocellular carcinoma, the compliance and dose intensity of the drug were quite low compared with other trials. Although not only identified pharmacogenomics differences but also differences in social environment, and regional medical care, including pharmacoeconomics strongly influence ethnic differences in treatment response, further identification and understanding of the pharmacogenomics underlying ethnic differences will be essential to timely and reliable global development of new anticancer drugs.
Antineoplastic Combined Chemotherapy Protocols/adverse effects/*therapeutic use ; Asian Continental Ancestry Group ; Carcinoma, Non-Small-Cell Lung/drug therapy/ethnology ; Chemoembolization, Therapeutic ; Clinical Trials as Topic ; Drug Design ; Ethnic Groups ; Humans ; Japan ; Lung Diseases, Interstitial/chemically induced ; Lung Neoplasms/drug therapy/ethnology ; Mutation ; Pharmacogenetics/*methods ; Receptor, Epidermal Growth Factor/genetics ; Republic of Korea

BACKGROUNDGemcitabine plus cisplatin is a standard treatment for stages IIIB and IV nonsmall cell lung cancer (NSCLC). This randomized phase II study evaluated a 3-week versus a 4-week schedule of gemcitabine-cisplatin as first line treatment for Chinese patients with advanced NSCLC.

METHODSPatients were randomized to receive cisplatin 75 mg/m(2) on day 1 plus either gemcitabine 1250 mg/m(2) on days 1 and 8 of a 21-day cycle (3-week group) or gemcitabine 1000 mg/m(2) on days 1, 8 and 15 of a 28-day cycle (4-week group).

RESULTSOne hundred patients were enrolled in this study. The response rate was 24% (12/51 patients) in the 3-week group and 27% (13/49 patients) in the 4-week group. There were no statistically significant differences between the two treatment groups in survival (hazard ratio: 1.19; 95% CI: 0.68 - 2.09) with a median survival of 12.1 months and 13.8 months in the 3-week group and the 4-week group respectively. The rate of grade 3/4 toxicity in the 3-week group was 55% compared with 86% in the 4-week group (P = 0.001). The difference in the incidence of grade 3/4 haematological toxicities did not reach statistical significance (3-week: 37%, 4-week: 57%), however grade 3/4 drug related neutropenia (3-week: 27%, 4-week: 51%) and thrombocytopenia (3-week: 8%, 4-week: 31%) were significantly lower in the 3-week group. Grade 3/4 nonhaematological toxicities were less in the 3-week group (33% cf 63%; P = 0.005).

CONCLUSIONSThe differences in the efficacy endpoints were all in favour of the 4-week schedule of gemcitabine plus cisplatin, however these differences did not reach statistical significance. Fewer grade 3/4 toxicities were observed in the 3-week group compared with the 4-week group.

Adult ; Aged ; Antineoplastic Combined Chemotherapy Protocols ; therapeutic use ; Asian Continental Ancestry Group ; statistics & numerical data ; Carcinoma, Non-Small-Cell Lung ; drug therapy ; ethnology ; China ; Cisplatin ; administration & dosage ; Deoxycytidine ; administration & dosage ; analogs & derivatives ; Drug Administration Schedule ; Female ; Humans ; Lung Neoplasms ; drug therapy ; ethnology ; Male ; Middle Aged ; Treatment Outcome