BACKGROUND: The Panitumumab Randomized trial In combination with chemotherapy for Metastatic colorectal cancer to determine Efficacy (PRIME) demonstrated that panitumumab-FOLFOX4 significantly improved progression-free survival (PFS) versus FOLFOX4 as first-line treatment of wild-type (WT) KRAS metastatic colorectal cancer (mCRC), the primary end point of the study. PATIENTS AND METHODS: Patients were randomized 1:1 to panitumumab 6.0 mg/kg every 2 weeks + FOLFOX4 (arm 1) or FOLFOX4 (arm 2). This prespecified final descriptive analysis of efficacy and safety was planned for 30 months after the last patient was enrolled. RESULTS: A total of 1183 patients were randomized. Median PFS for WT KRAS mCRC was 10.0 months [95% confidence interval (CI) 9.3-11.4 months] for arm 1 and 8.6 months (95% CI 7.5-9.5 months) for arm 2; hazard ratio (HR) = 0.80; 95% CI 0.67-0.95; P = 0.01. Median overall survival (OS) for WT KRAS mCRC was 23.9 months (95% CI 20.3-27.7 months) for arm 1 and 19.7 months (95% CI 17.6-22.7 months) for arm 2; HR = 0.88; 95% CI 0.73-1.06; P = 0.17 (68% OS events). An exploratory analysis of updated survival (>80% OS events) was carried out which demonstrated improvement in OS; HR = 0.83; 95% CI 0.70-0.98; P = 0.03 for WT KRAS mCRC. The adverse event profile was consistent with the primary analysis. CONCLUSIONS: In WT KRAS mCRC, PFS was improved, objective response was higher, and there was a trend toward improved OS with panitumumab-FOLFOX4, with significant improvement in OS observed in an updated analysis of survival in patients with WT KRAS mCRC treated with panitumumab + FOLFOX4 versus FOLFOX4 alone (P = 0.03). These data support a positive benefit-risk profile for panitumumab-FOLFOX4 for patients with previously untreated WT KRAS mCRC. KRAS testing is critical to select appropriate patients for treatment with panitumumab.

Department of Biostatistics Amgen Inc Thousand Oaks

Department of Global Development Amgen Inc Thousand Oaks USA

Department of Medical Oncology Centre René Gauducheau Nantes France

Department of Medical Oncology Hospital de Gastroenterología Buenos Aires Argentina

Department of Medical Oncology Hospital Universitario Marqués de Valdecilla Santander Spain

Department of Medical Oncology Université Catholique de Louvain Brussels Belgium

Department of Medical Oncology University of Witwatersrand Faculty of Health Sciences Johannesburg South Africa

Department of Medical Oncology Vall d'Hebron University Hospital Barcelona Spain

Department of Medical Sciences Amgen Inc Thousand Oaks

Department of Medicine Division of Hematology Oncology Mount Sinai Hospital Toronto Canada

Department of Oncology and Hematology Grand Hôpital de Charleroi Charleroi Belgium

Department of Oncology and Radiotherapy Medical University of Gdańsk Gdańsk Poland

Department of Oncology Institut Onkologie a Rehabilitace na Plesi s r o Nová Ves pod Pleší Czech Republic

Department of Oncology Szent Laszlo Hospital Budapest Hungary

Department of Oncology The Credit Valley Hospital Mississauga Canada

Division of Cancer Sciences and Molecular Pathology The Beatson West of Scotland Cancer Centre Glasgow UK

Division of Medical Oncology Ospedale Niguarda Ca' Granda Milan Italy

Gastrointestinal Unit The Royal Marsden NHS Foundation Trust London UK

Oncology Department Masarykuv Onkologicky Ustav Brno Czech Republic

Proliferative Diseases Branch Copernicus Memorial Hospital Lodz Poland

References provided by Crossref.org

Prospective Observational Cohort Study to Describe the Use of Panitumumab in Combination with Chemotherapy in Real-World Clinical Practice for Patients with Wild-Type RAS mCRC