Phase III trial of Vectibix (panitumumab) in metastatic colorectal cancer meets primary endpoint- Amgen

Amgen has announced detailed results of a Phase III study with Vectibix (panitumumab) and best supportive care (BSC) compared to BSC alone in patients with chemorefractory wild-type KRAS (exon 2) metastatic colorectal cancer (mCRC; n=377 total). The study met its primary endpoint, demonstrating a statistically significant improvement in overall survival (OS). 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 tumor mutation status in its primary analysis, providing important information about OS in these populations. The study 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. 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. Patients with mutant RAS mCRC did not benefit from Vectibix treatment. 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. These results were presented at the 2016 Gastrointestinal Cancers Symposium.

Comment: in May 2014 the FDA approved a KRAS diagnostic developed by Qiagen which can be used to help diagnose the genetic profile of tumours in patients with colorectal cancer.