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Amgen announced the presentation of detailed results of a Phase III study with Vectibix® (panitumumab) and best supportive care (BSC) compared to BSC alone. The study met its primary endpoint, demonstrating a statistically significant improvement in overall survival (OS) in patients with chemorefractory wild type KRAS (exon 2) metastatic colorectal cancer (mCRC; n=377 total). This is the first Phase III Vectibix study to include an analysis of efficacy of Vectibix by wild-type KRAS (exon 2) and in wild-type RAS tumour mutation status in its primary analysis, providing important information about OS in these populations. These results, in addition to secondary endpoint data, were presented at the 2016 Gastrointestinal Cancers Symposium (GICS) in San Francisco.
The study (GICS abstract #642) showed that patients with wild-type KRAS (exon 2) mCRC treated with Vectibix and BSC achieved a median OS of 10 months compared to 7.4 months for patients treated with BSC alone (hazard ratio [HR]=0.73, 95% confidence interval [CI]=0.57-0.93, p=0.0096). Data from a key secondary endpoint showed that patients with wild-type RAS (absence of mutations in exons 2, 3 and 4 of KRAS and NRAS) mCRC treated with Vectibix and BSC achieved a median OS of 10 months compared to 6.9 months for patients treated with BSC alone (n=270; HR=0.70, 95% CI=0.53-0.93, p=0.0135).
Patients with mutant RAS mCRC did not benefit from Vectibix treatment (n=54; OS HR=0.99, 95% CI=0.49-2.00). The safety profile was comparable to the known safety profile of Vectibix when administered as a single agent, with skin, nail, gastrointestinal and electrolyte disorders being the most frequently reported adverse events.
“Amgen has played a significant role in the advancement of personalised medicine, applying cutting-edge science and technology in our efforts to target therapies to the patients who are most likely to benefit. Amgen is committed to understanding cancer biology through studies like this,” said Sean E Harper, MD, executive vice president of Research and Development at Amgen. “As well as providing additional insights into the way Vectibix works in mCRC, these data support expanding biomarker screening to include wild-type RAS.”
Colorectal cancer is the third most common cancer worldwide, with approximately 1.2 million cases occurring globally each year.1,2 Approximately 20% of colon cancers are diagnosed at the metastatic stage, when the disease has already spread to distant organs, a diagnosis associated with only a 12% five-year survival rate.3 Using molecular approaches to identify unique genetic signatures in mCRC has the potential to help improve treatment outcomes. Of the few biomarkers in colorectal cancer, RAS genes (KRAS, NRAS) have a validated impact on treatment outcomes.4,5
Abstracts are currently available on the GICS website.