NE Oncology Issue – June 2007
The data from the presentations at ASCO indicate that panitumumab is certainly very similar to cetuximab with regards to the efficacy and side effects profile. Panitumumab has the added advantage of slightly lower side effects and toxicity profile. The data from the patient-reported outcome (PRO)–assessed clinical benefit trial by Hendlisz, et al. 1 are therefore very exciting. This trial is a crossover design which is why we do not see the hugely significant survival with panitumumab that was seen with cetuximab in the trial by Au et al.2 We do see, however, that the disease-related symptom scores and HRQoL scores are in favour of panitumumab.
In the safety study by Peeters, et al.,3 the authors clearly demonstrate that panitumumab is generally well tolerated and has a toxicity profile similar to that of cetuximab. Skin toxicities are by far the most common toxicities experienced by patients undergoing anti-EGFR therapy. The association of severity of skin reaction with better PFS outcomes in panitumumab-treated patients has further been confirmed by the Berlin, et al. study.4 Their study demonstrates that increased skin rash correlates with efficacy similar to what is seen with cetuximab.
Thus far, clinical trials with cetuximab and panitumumab have been conducted in colorectal cancer patients whose tumours have been shown to be positive for EGFR by IHC. In this context, it is interesting to note that Mitchell, et al. 5 have reported that panitumumab can be effective even in patients with refractory metastatic colorectal cancer and patients with low or negative tumour membrane EGFR levels.5 We have a treatment that will actually work whether a patient with colorectal cancer has a high or low EGFR-expressing tumour. We look forward to using panitumumab once it is available in Canada. The fact that we might not need to assay tumour EGFR levels to be able to use panitumumab is an important clinical factor as well.
References: 1. Hendlisz A, Van Cutsem E, Peeters M, et al. Patient-reported outcome (PRO)-assessed clinical benefit with panitumumab (Pmab) in metastatic colorectal cancer (mCRC) patients (pts). Program and abstracts of the 43rd American Society of Clinical Oncology Annual Meeting; June 1–5, 2007; Chicago, Illinois; Abstract 6560. 2. Au H, Karapetis C, Jonker D, et al. Quality of life in patients with advanced colorectal cancer treated with cetuximab: results of the NCIC CTG and AGITG CO.17 trial. Program and abstracts of the 43rd American Society of Clinical Oncology Annual Meeting; June 1–5, 2007; Chicago, Illinois; Abstracts 4002. 3. Peeters M, Van Cutsem E, Berlin J. Safety of panitumumab, a fully human monoclonal antibody against the epidermal growth factor receptor (EGFr), in patients (pts) with metastatic colorectal cancer (mCRC) across clinical trials. Program and abstracts of the 43rd American Society of Clinical Oncology Annual Meeting; June 1–5, 2007; Chicago, Illinois; Abstract 4138. 4. Berlin J, Van Cutsem E, Peeters E, et al. Predictive value of skin toxicity severity for response to panitumumab in patients with metastatic colorectal cancer (mCRC): a pooled analysis of five clinical trials. Program and abstracts of the 43rd American Society of Clinical Oncology Annual Meeting; June 1–5, 2007; Chicago, Illinois; Abstract 4134. 5. Mitchell EP, Hecht JR, Baranda J, et al. Panitumumab activity in metastatic colorectal cancer (mCRC) patients (pts) with low or negative tumor epidermal growth factor receptor (EGFR) levels: an updated analysis. Program and abstracts of the 43rd American Society of Clinical Oncology Annual Meeting; June 1–5, 2007; Chicago, Illinois; Abstract 4082.
Vera Hirsh, MD, FRCPC
Chief of the Hematology-Oncology Service, Santa Cabrini Hospital
Associate Professor, Medicine and Oncology, McGill University
Associate Physician, Oncology Service, at the Royal Victoria, Montreal General, and Montreal Chest Hospitals
With a current practice in both hematology and oncology, Dr. Vera Hirsh is an associate professor of medicine and oncology at McGill University. Her research at the Quebec Pulmonary Unit focuses on the treatment of lung cancer, and she continues to chair ongoing international chemotherapy trials. Dr. Hirsh chaired the Quebec Lung Cancer Committee to establish guidelines for the treatment of lung cancer. In addition, she has published abstracts, articles, and book chapters. Dr. Hirsh is a member of advisory boards for many pharmaceutical companies and the Medical Oncology Standing Committee of RTOG.
Christine Cripps, MD, FRCPC
Medical Oncologist, Director,
Continuing Medical Education,
Ottawa Hospital Regional Cancer Centre
Dr. Christine Cripps is a medical oncologist and director of the Continuing Medical Education Department at the Ottawa Hospital Regional Cancer Centre. She also holds a position of Associate Professor, Medicine at the University of Ottawa. A keen teacher, Dr. Cripps’ main areas of interest include gastrointestinal cancer and head and neck cancer. She also enjoys cycling, skiing, and sailing when time permits.
Stephen K. L. Chia, MD, FRCPC
Assistant Professor of Medicine Department of Medicine
University of British Columbia
British Columbia Cancer Agency
Dr. Chia is a staff oncologist with the British Columbia Cancer Agency (BCCA), Vancouver, Canada. He also serves as physician coordinator for both the breast cancer and head and neck cancer clinical trials at the BCCA – Vancouver Cancer Centre. He is an active researcher in phase I-III trials in breast cancer, head and neck cancer and investigational new drugs. He is currently carrying out studies in breast cancer with grant funded research from the National Cancer Institute of Canada, Canadian Breast Cancer Alliance and Canadian Breast Cancer Foundation – British Columbia/Yukon Chapter. Dr. Chia is an active member of the British Columbia Breast Tumor Group, Breast Cancer Systemic Policy Group and Head and Neck Tumor Group.
José Chang, MD, FRCPC
Head of Medical Oncology, RS
McLaughlin Durham Regional Cancer Centre, Oshawa
Dr. José Chang is the principal investigator and site representative for the National Cancer Institute of Canada Clinical Trials Group, and is an examiner for the Medical Council of Canada. His research interests lie in the areas of breast cancer, melanoma, lymphoma, and quality of life during chemotherapy. Dr Chang has presented at major oncology meetings of the American Society of Clinical Oncology, San Antonio Breast Cancer Symposia, and European Breast Cancer Conference. A member of the editorial board of the journal Current Oncology, Dr. Chang has published in journals such as the Journal of Clinical Oncology, European Journal of Cancer, and Canadian Medical Association Journal.