Unexpected toxicity of cetuximab combined with conventional chemoradiotherapy in patients with locally advanced anal cancer: results of the UNICANCER ACCORD 16 phase II trial.

Background: The ACCORD 16 phase II trial aimed to evaluate the objective response rate after combination of conventional chemoradiotherapy (CRT) and cetuximab in locally advanced anal canal carcinoma (LAACC).

Patients And Methods: Immunocompetent patients with histologically confirmed LAACC received CRT [45 gray (Gy)] in 25 fractions over 5 weeks, fluorouracil and cisplatin during weeks 1 and 5), in combination with weekly dose of cetuximab (250 mg/m(2) with a loading dose of 400 mg/m(2) 1 week before irradiation), and a standard dose boost (20 Gy). The trial was originally designed to include 81 patients to detect a 15% of objective response increase with the new combination in comparison with CRT.