An Open-Label, Single-Arm Study Assessing Safety and Efficacy of Panitumumab in Patients With Metastatic Colorectal Cancer Refractory to Standard Chemotherapy

Ann Oncol. 2008 Jan;19(1):92-8. doi: 10.1093/annonc/mdm399. Epub 2007 Sep 4.

Abstract

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.

Publication types

  • Clinical Trial, Phase III
  • Multicenter Study
  • Randomized Controlled Trial

MeSH terms

  • Adenocarcinoma / drug therapy
  • Adenocarcinoma / mortality
  • Adenocarcinoma / therapy*
  • Adult
  • Aged
  • Aged, 80 and over
  • Antibodies, Monoclonal / adverse effects
  • Antibodies, Monoclonal / therapeutic use*
  • Antineoplastic Combined Chemotherapy Protocols / therapeutic use
  • Colorectal Neoplasms / drug therapy
  • Colorectal Neoplasms / mortality
  • Colorectal Neoplasms / therapy*
  • Disease Progression
  • Disease-Free Survival
  • Drug Eruptions / etiology
  • Drug Resistance, Neoplasm
  • ErbB Receptors / antagonists & inhibitors*
  • ErbB Receptors / immunology
  • Female
  • Humans
  • Immunotherapy* / adverse effects
  • Immunotherapy* / statistics & numerical data
  • Male
  • Middle Aged
  • Neoplasm Proteins / antagonists & inhibitors*
  • Neoplasm Proteins / immunology
  • Panitumumab
  • Salvage Therapy* / statistics & numerical data
  • Survival Analysis

Substances

  • Antibodies, Monoclonal
  • Neoplasm Proteins
  • Panitumumab
  • EGFR protein, human
  • ErbB Receptors