The American Society for Clinical Oncology (ASCO) has published a provisional clinical opinion (PCO) advising doctors to test patients with colorectal cancer for KRAS mutations before treating them with medicines that include Erbitux® (cetuximab) or Vectibix™ (panitumumab).

The consensus of experts who reviewed recent research was that patients with metastatic colorectal cancer whose tumors have mutations in the KRAS gene do not benefit from treatment that targets the epidermal growth factor receptor (anti-EGFR therapy).  Patients should be tested for KRAS mutations and, if those mutations are found, not receive anti-EGFR antibodies as part of their treatment..

A PCO, based on expert consensus, is designed to help decision-making for oncologists faced with major research results that can potentially change the way they treat patients. Read the rest of this entry »

Another mutated gene has been discovered that appears to cause resistance to treatment with the EGFR inhibitors Erbitux® (cetuximab) and  Vectibix™ (panitumumab).

Only a fraction of patients who receive Erbitux or Vectibix respond to it.  There is now convincing evidence that the 30 to 40 percent of colorectal cancer patients whose tumors have mutated KRAS genes don’t benefit, but what about others who have normal or wild-type KRAS and don’t respond either?

Scientists in Italy have found that about 12 percent of wild-type patients have a mutation in their tumor’s BRAF gene, and these patients showed no response to Erbitux or Vectibix. Read the rest of this entry »