In a nutshell
This study looks at the use of panitumumab and irinotecan as a combination treatment in patients with KRAS wild-type (non-mutated) metastatic colorectal cancer which has continued to progress while on standard chemotherapy (oxaliplatin, fluoropyrimidines, irinotecan, bevacizumab).
Some background
Cancer cells can have receptors on their surface called epidermal growth factor receptors (EGFR). These receptors pick up signals that make cells grow. Drugs such as cetuximab and panitumumab are EGFR inhibiting drugs which aim to stick to the receptors on the tumors stopping them from getting a signal to grow. Other drugs such as irinotecan inihibt DNA replication and stop cell division. These drugs can be used at the same time as chemotherapy treatment.
A gene called KRAS is involved in the normal working of growth factors and receptors. The normal gene is often referred to as the wild type gene. However, genes can become damaged or mutated. Mutations in the KRAS gene are present in about 40% of colorectal cancers.
Methods & findings
This study followed 65 patients who had metastatic colorectal cancer. 54 patients had wild-type KRAS. These patients had previously been treated with irinotecan, oxaliplatin and fluoropyrimidines with or without bevacizumab. However, their tumors had progressed while being treated with this irinotecan-based chemotherapy. These patients were threfore treated with a chemotherapy regimen containing an intravenous infusion of panitumumab just before the administration of irinotecan on day 1 of each cycle. These cycles were given every two weeks until cancer progression or unacceptable toxicity.
Results showed that the patients without KRAS mutations (wild-type) benefited from this treatment; progression-free and overall survivals were 5.5 and 9.7 months, respectively. Patients with mutations did not benefit from the combined treatment with panitumumab and irinotecan.
The bottom line
Overall this study shows that panitumumab is an appropriate treatment for patients without KRAS mutations (wild-type).
The fine print
A potential weakness of this study is the limited number of participants.
Published By :
Annals of oncology
Date :
Jan 14, 2013
Tags: Confined or spread disease-Spread with distant metastasis, Current disease status-First occurrence of the cancer, Current treatment status-Undergoing active treatment-No response, Current treatment status-Undergoing active treatment-Progressive despite several lines of treatment, Current treatment status-Undergoing active treatment-Progressive despite treatment, Library Item, Performance status-2 - Symptomatic, 50 in bed, Research, Treatment, Treatment(s) already received-Chemotherapy, Treatment(s) now being considered-Experimental drug, Treatment(s) now being considered-Immunotherapy, Type(s) of chemotherapy-Single drug-Fluorouracil (5-FU, Efudex), Type(s) of chemotherapy-Single drug-Irinotecan (Campto)
