Merck KGaA’s targeted cancer therapy Erbitux (cetuximab) has been shown to significantly prolong progression-free survival and increase overall response rate in metastatic colorectal cancer patients, an area of cancer care where patients currently have limited treatment options.

The International EPIC (European prospective Investigation of Cancer) compared Erbitux plus irinotecan-based chemotherapy with irinotecan-based chemotherapy alone in patients who had failed first-line oxaliplatin-based chemotherapy. Progression-free survival increased by over 50% in patients receiving Erbitux, while overall response rate was nearly four times higher in the Erbitux group compared with the irinotecan-only group.

Lead study investigator, Professor Alberto Sobrero of Hospedale San Martino in Italy commented: “We are very encouraged by these new data. There are limited possibilities available for patients whose cancers have progressed on oxaliplatin-based therapies. These findings demonstrate that the addition of Erbitux to patients who have failed oxaliplatin-based therapy gives patients and physicians a new treatment option, and an opportunity to keep the disease at bay for longer. The EPIC study adds to the rapidly accumulating evidence base for Erbitux, which is proving to be one of the most active targeted therapies available for a range of tumour types.”

While overall survival didn’t differ significantly between the two trial arms, at 10.71 months versus 9.99 months, Merck suggests the reason may be because over 40% of patients in the control group compared to 11% in the Erbitux arm were given Erbitux as well as irinotecan in combination with Erbitux following disease progression. With patients in both arms of the trial receiving Erbitux, the ultimate survival difference between the two study groups could have been minimised, the company said.

Extended dosing regimen explored

The findings, which were presented on April 16 at the American Association for Cancer Research (AACR) meeting, also included data from a Phase I study which indicates that Erbitux, which is usually given once a week, could be safely administered once every two weeks.

Successive cohorts of patients were enrolled into the study arms and received escalating doses of Erbitux, with pharmacokinetics and safety profiles assessed for each. Erbitux, administered every two weeks at a dose of 500mg/m2, showed comparable pharmacokinetics to the current weekly regimen..

Erbitux has also proven effective in prolonging overall survival in other cancer-based trials. The drug showed a survival benefit in heavily pre-treated patients in metastatic CRC when compared with Best Supportive Care, and in a trial comparing Erbitux plus radiotherapy with radiotherapy alone in locally advanced squamous cell carcinoma of the head and neck, median survival extended by 20 months in the Erbitux arm.