Cetuximab’s enhanced efficacy in high EGFR expressors occurred in both the 135 patients with an adenocarcinoma, and in the 144 patients with a squamous cell carcinoma. Among the high expressors, cetuximab also had significantly better performance measures by tumor response rate, with a twofold higher response rate with cetuximab compared with controls (P = .002), and by time-to-treatment-failure, with a statistically significant, average 22% drop in this time (P = .026) with cetuximab compared with controls.
But focusing on high expressors did not result in a significantly improved duration of progression-free survival. The analysis also showed no increased rate of safety issues in the high expressors who received cetuximab, including no increased rate of skin or subcutaneous disorders.
The FLEX study was funded by Merck, which markets cetuximab (Erbitux) outside the United States. Dr. Pirker disclosed relationships with seven companies, including Merck and Eli Lilly, which markets cetuximab in the United States. Dr. Herbst also cited ties to numerous companies, including ImClone, a Lilly subsidiary that developed cetuximab. Dr. Scagliotti had relationships with four companies, including Lilly.