Vectibix® (panitumumab) appears to improve overall survival among patients with wild-type KRAS metastatic colorectal cancer that has progressed on or following chemotherapy. A Phase III trial of Vectibix is currently underway, but researchers have announced that that drug has extended overall survival, the primary goal of the study.
Vectibix is a targeted therapy that inhibits cancer cell growth and survival by targeting a protein known as the epidermal growth factor receptor (EGFR). Vectibix has been approved since 2006 for the treatment of EGFR-expressing metastatic colorectal cancer that has progressed on or following chemotherapy that contains fluoropyrimidine, oxaliplatin, and irinotecan. An estimated 40–50% of metastatic colorectal cancers contain a gene known as KRAS. Vectibix appears to benefit only those patients whose cancers do not contain the mutation. This is refereed to as wild-type KRAS.
In 2014 the FDA approved Vectibix for use in combination with FOLFOX (leucovorin-fluorouracil-Eloxatin® [oxaliplatin]), as first-line treatment in patients with wild-type KRAS metastatic colorectal cancer.
In this current study, which compared Vectibix plus best supportive care with best supportive care alone, Vectibix has significantly extended overall survival, the primary focus (or endpoint) of the trial. In addition, Vectibix has extended progression-free survival, a secondary endpoint of the study.
The researchers didn’t observe any new or unknown side effects associated with treatment with Vectibix. Common side effects (affecting more than 30% of patients) include skin reactions and low level of magnesium in the blood (hypomagnesemia).
According to biopharmaceutical company Amgen, makers of Vectibix, full results of this trial will be released at an upcoming medical congress and will be published at a later date.
“These positive overall survival results for Vectibix reinforce the importance of KRAS and RAS biomarkers in making treatment decisions in metastatic colorectal cancer,” said Sean E. Harper, MD, executive vice president of Research and Development at Amgen.
Reference: Results From Phase 3 Trial Show Vectibix® (Panitumumab) Improves Overall Survival In Chemorefractory Wild-Type KRAS Metastatic Colorectal Cancer Versus Best Supportive Care [press release]. Amgen website. Available at: https://www.amgen.com/media/media_pr_detail.jsp?year=2015&releaseID=2060682. Accessed August 3, 2015.
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