Findings reported at a cancer meeting in Switzerland show a strong correlation between the efficacy of cetuximab (Erbitux) and the degree of skin toxicity in patients with metastatic colorectal cancer. “This is a clear and important finding,” said Dr. Eric Van Cutsem, from University Hospital Gasthuisberg in Leuven, Belgium.
“The more rash, the more severe the rash, the more efficient the treatment is and the longer the survival,” Dr. Van Cutsem told a news briefing today at the EORTC-NCI-AACR Symposium on Molecular Targets and Cancer Therapeutics underway in Geneva. The conference is sponsored by the European Organization for Research and Treatment of Cancer (EORTC), the U.S. National Cancer Institute (NCI) and the American Association for Cancer Research (AACR).The international study involved 346 patients with advanced colorectal cancer expressing epidermal growth factor receptor (EGFR) who had failed at least two prior chemotherapy regimens containing irinotecan, oxaliplatin, and a fluoropyrimidine. They were treated with cetuximab monotherapy at a starting dose of 400 mg/m? followed by 250 mg/m? weekly. Treatment continued until disease progression or unacceptable toxicity.Overall, 12% of patients achieved partial tumor responses and survived a median of 6.6 months. Altogether, 87% of patients developed an acne-like rash, a common side effect of cetuximab.Data analysis showed that patients with grade 2 (n=141) or grade 3 rash (n=17) had a statistically significantly better tumor response rate and median survival rate than those with grade 1 rash (n=142) or no rash (n=46).Respectively, 18% and 24% of patients with grade 2 and 3 rash responded to cetuximab compared with 8% of patients with grade 1 rash and none of those with no rash.Median survival was 13 months and 8.9 months in patients with grade 2 and 3 rash, respectively, compared with 4.9 and 2.1 months in those with grade 1 or no rash.Dr. Van Cutsem acknowledged that at present “we don’t have a clear explanation for the correlation between skin reaction and response rate and survival with cetuximab monotherapy.”He and his colleagues hope to learn more about the link between rash and cetuximab efficacy in a recently launched randomized prospective study designed specifically to look at this issue.(Source: Reuters Health News: Megan Rauscher: Oncolink: October 2004.)