Prospective Phase II Trial of Second-line FOLFIRI in Patients with Advanced Colorectal Cancer Including Analysis of UGT1A1 Polymorphisms: FLIGHT 2 Study

Patients and Methods

Inclusion and exclusion criteria. Patients with histologically-confirmed metastatic or locally recurrent colorectal cancer and measurable disease by the response evaluation criteria for solid tumor (RECIST) criteria 1.0 add reference to list were considered candidates for this study. All patients were regarded to have developed progressive disease while receiving or within six months after discontinuing palliative or adjuvant fluoropyrimidine-based chemotherapy. Eligibility criteria also included age ≥20 years; Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0-2, adequate bone marrow function (leucocyte count ≥3,000 and ≤12,000/μl, hemoglobin ≥8.0g/dl, and platelet count ≥10⁵/μl); serum creatinine level ≤1.5 mg/dl; total bilirubin level ≤1.5 mg/dl; (AST) and (ALT) ≤100 IU/l; qualitative urine protein ≤(1+). Patients were excluded if they had the following: known central nervous system metastasis; other active double cancer; inadequately-controlled cardiovascular disease, diabetes or diarrhea; interstitial pneumonia or pulmonary fibrosis; previous history of vascular thromboembolism or severe drug hypersensitivity; bleeding tendency; hepatic B or C virus infection; any form of surgery within four weeks of study enrollment; pregnant or lactating. Informed consent according to Institutional regulations was obtained from all patients prior to study entry.

Genotyping of UGT1A1. Genomic DNA was extracted from 7 ml of whole blood collected into a tube with EDTA-2Na by the conventional NaI method. The number of TA repeats in the UGT1A1 promoter region was then determined by fragment sizing, (PCR) was performed as described previously (13). To confirm the genotype data obtained by fragment size analysis, direct sequencing was performed and genotypes were assigned based on the number of TA repeats in each allele (6/6 or 7/7). In addition, UGT1A1*6 polymorphism G71R(*6) was analyzed by the PCR-restriction fragment length polymorphism method, as described elsewhere (13).

Treatment schedule. The treatment regimen was based on a previously published phase II study (12). Chemotherapy, thus, consisted of irinotecan given at a dose of 150 mg/m² (instead of 180 mg/m² commonly utilized in Western countries) as a 90-min intravenous infusion on day 1. LV was given at a dose of 200 mg/m² as a 120 min intravenous infusion, followed by 5-FU (400 mg/m² as a bolus and then 2,400 mg/m² as a 46 h intravenous infusion) on days 1 and 2. In patients with homozygosity for UGT1A1*28, the starting dose of irinotecan was reduced to 100 mg/m², referring to the recommendation of an advisory meeting by the subcommittee of the Food and Drug Administration Center or Drug Evaluation and Research held in November 2004 (http://www.fda.gov/) and our previous phase I study in which the maximum tolerated dose of biweekly irinotecan was 100 mg/m² for patients with the UGT1A1*28 heterozygosity (1).

Treatment was repeated every two weeks until disease progression or dose-limiting toxicity occurred. Blood tests and clinical evaluation were performed every two weeks, before treatment. Chemotherapy could be administered if the leukocyte count was >3,000 mm³, neutrophil count was >1,500 mm³, platelet count >75000 mm³ and clinical toxicity resolved or grade 1.

Before each cycle, patients underwent clinical examination and hematological tests. All toxicities were reported according to the National Cancer Institute-Common Cytotoxicity Criteria (NCI-CTC) version 3. Chemotherapy was delayed until recovery to grade 1 hematological and non-hematological toxicity, if white blood cells were <1,500/m³, neutrophils were <500/m³ or platelets were <50,000/m³, or more grade 2 or more persistent non-hematological toxicity. 5-FU and irinotecan infusion doses were reduced to 80% dosage in subsequent cycles in cases of grade 3-4 toxicity. If any toxicity required a delay of more than two weeks, the patient was withdrawn from the study due to toxicity.

Pre-treatment and follow-up evaluation. Prior to initiating chemotherapy, all patients were assessed by physical examination, routine hematological and biochemical analyses, chest X-ray, and (CT) scans to define the extent of the disease. Complete blood cell counts with platelet and differential counts were obtained weekly during chemotherapy, and serum chemistries were repeated at least once every course. Subjective symptoms, physical examination, PS and all adverse reactions were recorded before each treatment cycle. Tumor size was measured every eight weeks, or earlier if worsening of the clinical condition occurred.

Assessment of response. The primary efficacy end-point was the response rate, which was evaluated according to the RECIST criteria. (CR) required the complete disappearance of all objective evidence of disease on two separate measurements at least four weeks apart. (PR) was defined as a more than 30% reduction in the sum of the diameters of measurable lesions without a CR, no progression of any lesion by more than 20%, or the appearance of any new lesion, confirmed on two separate measurements that were four weeks apart. In the case of bone metastases, CR was recorded only when there was complete disappearance of all lesions on X-Ray, and PR when the decrease in size or recalcification of lytic lesions occurred. X-Ray-negative disease was not taken into account. Progressive disease (PD) was defined as the enlargement of any existing measurable lesion by more than 20% or the development of new metastatic lesions. Stable disease (SD) was any measurement that did not fulfill the criteria for CR, PR or PD. All tumor measurements were reviewed and confirmed by an independent panel of oncologists and radiologists to confirm responses and the date of progression.

Secondary efficacy end-points included the duration of response (measured from the onset of the best response to the date of disease progression), progression-free survival (PFS; calculated from the start of treatment to the time of progression or relapse), and overall survival (OS) time.

Sample size and statistical analysis. The primary end-point of this study was the response rate to FOLFIRI based on the RECIST criteria, while OS, PFS and time-to-treatment failure (TTF) were the secondary end-points. The response rate was reported as a proportion with 95% binomial confidence interval (CI). OS was calculated from the day of the enrollment to death. PFS was determined from the day of the enrollment to the date without any progression or death. Patients alive at the final survival analysis or in when disease had not progressed at the time of the final analysis were censored using the last contact date. Survival curves were drawn by the Kaplan–Meier method and a CI for the median survival time is constructed using a non-parametric method (14). To assess the association between toxicity and UGT1A1 polymorphism, the chi-square test was used. Statistical significance was accepted when the p-value was less than 0.05.

Based on the report from Tournigand et al. (10), the overall response rate and disease control rate was reported as 4% and 35%, respectively. For a two-sided 95% CI for a binomial proportion whose true value is 4% and 35%, a sample size of 50 patients yields a half-width of at most 10% and 15%, with a conditional probability of 1. Therefore, the target sample size was determined to be 50 patients in this study.