Gefitinib and irinotecan in patients with fluoropyrimidine-refractory irinotecan-naïve advanced colorectal cancer (CRC): dose-finding, pharmacokinetics, safety and efficacy.
Authors: Hickish, T., Chau, I., Massey, A., Higgins, L., Osborne, R., Botwood, N., Swaisland, A. and Cunningham, D.C.
Journal: J Clin Oncol
Volume: 24
Issue: 18_suppl
Pages: 13520
eISSN: 1527-7755
Abstract:13520 Background: Gefitinib (IRESSA) is an oral epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor that has shown supra-additive activity in human CRC xenografts when combined with irinotecan. We have previously established that the recommended dose level (RDL) to be irinotecan 225mg/m(2) q3 weeks and gefitinib 250mg daily (Chau et al ASCO 2004). The dose limiting toxicities were neutropenia and diarrhoea. The continuation phase of this study aimed to evaluate the efficacy and safety of this combination. PATIENTS AND METHODS: Between Jun 2002 and Feb 2005, patients (pts) with advanced CRC progressing on or within 12 weeks of fluoropyrimidines-based chemotherapy, irinotecan-naïve and performance status ≤2 were recruited. Thirty-nine pts were treated with irinotecan and gefitinib in total with 27 treated at the RDL. RESULTS: Median age was 61 years (range: 31-79) and 13 (33.3%) pts were females. All pts were Caucasians (94.9%) and non-oriental Asians (5.1%). Thirteen (33.3%) pts had received (neo)adjuvant chemotherapy and 16 (41.0%) pts had prior oxaliplatin-based chemotherapy for metastatic disease. Grades 3-4 toxicities were anaemia 2.6%, neutropenia 15.4%, febrile neutropenia 10.3%, diarrhoea 35.9%, nausea 2.6%, vomiting 5.1%, lethargy 15.4% and skin rash 7.7%. For the pts treated at RDL, the objective tumour response rate was 11.1% (3 partial responses [PRs]; 95% confidence interval [CI]: 2.4-29.2%) and the disease control rate was 40.7% (3PRs, 8 stable diseases lasting for ≥12 weeks). The median time to progression was 4.2 months and median survival was 9.3 months. Six-month progression free survival was 22.2% (95% CI: 6.5-37.9%) and 6-month overall survival was 73.4% (95% CI: 56.5-90.3%). Preliminary pharmacokinetic data suggested that the addition of irinotecan to gefitinib resulted in an average of 14-33% increase in exposure to gefitinib (p<0.05). CONCLUSIONS: Irinotecan and gefitinib at this dose schedule was tolerable. Gefitinib did not appear to add substantial efficacy to irinotecan. The relative low dose of irinotecan at the RDL and the rarity of EGFR somatic mutation in CRC may be contributory to the modest activity of irinotecan and gefitinib combination. [Table: see text].
Source: PubMed