Erbitux falls short in colorectal cancer trial

US drugmakers ImClone Systems and Bristol-Myers Squibb say that treatment with combined Erbitux (cetuximab) plus irinotecan, failed to improve overall survival, compared with irinotecan alone, in patients with metastatic colorectal cancer. The firms added that the combined regimen did improve several secondary endpoints, including progression-free survival and treatment response rate.

The data, which was announced at the American Association for Cancer Research meeting in Los Angeles, demonstrated that Erbitux plus irinotecan improved median time-to-disease-progression in treated patients 54%, versus irinotecan alone. The companies added that this equates to a 31% reduction in the risk of disease-progression. In addition, patients in the therapy group were four times more likely to experience a 50% tumor reduction than those in the control group.

The firms said that the disappointing survival results, which follow on from mixed efficacy data reported earlier in the month (Marketletters April 5 and 12), may be a result of post-trial intervention. They explained that the similarity in overall survival rates between the treatment and control groups, which were 10.71 months and 9.99 months, respectively, despite the significant differences in response rate and progression-free survival times, may be due to improved survival in patients who went on to receive Erbitux having failed to respond to irinotecan alone.