Annals of Oncology Advance Access originally published online on September 4, 2007
Annals of Oncology 2008 19(1):92-98; doi:10.1093/annonc/mdm399
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gastrointestinal tumors |
An open-label, single-arm study assessing safety and efficacy of panitumumab in patients with metastatic colorectal cancer refractory to standard chemotherapy
1 Digestive Oncology Unit, University Hospital Gasthuisberg, Leuven, Belgium
2 Divisione Oncologia Falck, Ospedale Niguarda Cá Granda, Milan, Italy
3 Department of Medical Oncology, St-Luc University Hospital, Universite Catholique de Louvain, Brussels, Belgium
4 Department of Oncology-Hematology, Centre Hospitalier Notre Dame et Reine Fabiola, Charleroi, Belgium
5 Medical Oncology Service, Hospital Clinic de Barcelona, Ciberehd, Barcelona, Spain
6 Medical Oncology Unit 2, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
7 Kliniekhoofd Medische Oncologie, Oncologisch Centrum, UZ Brussel, Brussels, Belgium
8 Medical Oncology, Ashford Cancer Centre, Ashford, Australia
9 Department of Gastroenterology, Istituto Clinico Humanitas, Rozzano, Milan, Italy
10 Department of Internal Medicine I and Cancer Center, Medical University of Vienna, Vienna, Austria
11 Algoma District Cancer Program at Sault Area Hospital, Sault Sainte Marie, Ontario, Canada
12 Clinical Development, Amgen Inc ,Thousand Oaks, CA, USA
13 Medical Affairs Biostatistics, Amgen Ltd, Cambridge, UK
14 HepatoGastroenterology, Digestive Oncology Unit, Ghent University Hospital, Ghent, Belgium
* Correspondence to: Prof. E. Van Cutsem, University Hospital Gasthuisberg, 3000 Leuven, Belgium. Tel: +32-16-344218; Fax: +32-16-344419; E-mail: eric.vancutsem{at}uz.kuleuven.ac.be
Background: A phase 3 study demonstrated that panitumumab, a human monoclonal anti-epidermal growth factor receptor antibody, significantly prolonged progression-free survival versus best supportive care (BSC) in patients with chemorefractory metastatic colorectal cancer.
Patients and methods: This open-label extension study evaluated panitumumab monotherapy in BSC patients with radiographically documented disease progression in the phase 3 study. Patients received panitumumab 6 mg/kg every 2 weeks. The primary end point was safety; efficacy was also evaluated.
Results: One hundred and seventy-six patients were randomly assigned to the BSC arm of the phase 3 study received 
1 panitumumab dose in this extension study. Panitumumab was well tolerated. The most frequent treatment-related adverse events were skin toxic effects. Three (2%) patients had a grade 4 treatment-related adverse event. There were no infusion reactions. One (0.6%) patient had a complete response; 19 (11%) patients had a partial response; and 58 (33%) patients had stable disease. Median progression-free survival time was 9.4 [95% confidence interval (CI): 8.0–13.4) weeks. Median overall survival time was 6.3 (95% CI: 5.1–6.8) months. Anti-panitumumab antibodies were detected in 3 (4.2%) of 71 patients with a post-baseline sample.
Conclusions: These findings are comparable to those from the phase 3 study and support panitumumab monotherapy for chemorefractory colorectal cancer.
Key words: crossover, EGFr, extension study, fully human antibody, metastatic colorectal cancer, panitumumab
Received for publication April 1, 2007. Revision received July 10, 2007. Accepted for publication July 11, 2007.