Biotechnology giant Amgen has reported a mixed set of results from a Phase III trial of Vectibix in colorectal cancer, in which one co-primary endpoint was achieved but the other failed.

In the global, multicenter, double-blind, placebo-controlled Phase III study, 1,186 patients were randomised to receive either a combination of 6.0 mg/kg of Vectibix – a fully human EGFR antibody - and FOLFIRI (an irinotecan-based chemotherapy) or the latter alone every two weeks.

On the plus side, results showed that Vectibix (panitumumab) significantly improved progression-free survival in combination with FOLFIRI compared to the chemotherapy regimen alone in patients with metastatic colorectal cancer who carried unmutated forms of the KRAS protein.

But on a sour note, there was no statistically significant improvement in median overall survival in patients receiving the drug, although there was a numerical difference between the two treatment arms, the group said.

The company remained upbeat about the results, however, with Roger Perlmutter, the firm’s executive vice president of research and development, said stressing that Vectibix “has now demonstrated improved progression-free survival in Phase III trials with KRAS wild-type tumors in both first- and second-line treatment of metastatic colorectal cancer”. In addition, he said the results “add to the growing body of evidence confirming the utility of KRAS as a predictive biomarker” of treatment response.

Analysts largely seem to have erred on the positive side in their reactions to the news, perhaps because, as claimed by JP Morgan analyst Geoffrey Meacham, cited by Reuters, the results will give the drug a better chance of gaining regulatory approval in the second line treatment of the disease, which could substantially boost its currently rather meagre sales compared with those of its rival Erbitux (cetuximab; Imclone).