Yesterday, Amgen Inc. (AMGN) reported mixed top-line results from a phase III study evaluating Vectibix in combination with FOLFIRI (an irinotecan-based chemotherapy) as a second-line treatment for metastatic colorectal cancer (mCRC). The trial had two primary endpoints – progression-free and overall survival.

Results showed that Vectibix, in combination with FOLFIRI, significantly improved progression-free survival (compared to FOLFIRI alone) in mCRC patients with tumors harboring the wild-type or un-mutated forms of KRAS. KRAS is a protein, which plays an important role in cell growth regulation.

While the results were numerically greater, the Vectibix arm failed to achieve statistical significance. Meanwhile, the addition of Vectibix did not have any effect on the progression-free or overall survival in patients with tumors harboring the mutated form of KRAS.

Earlier this month, Amgen presented positive results from another phase III study in which Vectibix, in combination with FOLFOX (an oxaliplatin-based chemotherapy), significantly prolonged progression-free survival (PFS) compared with FOLFOX alone in the first-line treatment of patients with KRAS wild-type mCRC. Detailed results from both studies will be presented at an upcoming cancer conference in Europe in September 2009.

Vectibix is currently approved for the third-line treatment of patients suffering from mCRC. Amgen is looking to drive Vectibix sales by expanding the label into second and first-line treatment of metastatic colorectal cancer, which will increase the patient base significantly.

Colorectal cancer is the fourth most common cancer in men and the third most common cancer in women worldwide. Colorectal cancer is the second leading cause of cancer-related death in the Western world with more than 630,000 deaths occurring every year. We believe the results on Vectibix could help the product gain approval in the second-line treatment setting. With an expanded label, Vectibix will look to gain share from its main competitor, Eli Lilly’s (LLY) Erbitux. 

We currently have a Neutral rating on Amgen. We expect investor focus to remain on the approvability of key pipeline candidate, denosumab, which is the future of Amgen. A response from the FDA should be out by Oct 19, 2009.

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