Longer survival. Slower tumor progression.
ERBITUX with FOLFIRI (chemotherapy) in a clinical study helped some people with KRAS wild-type, EGFR-expressing metastatic colorectal cancer (mCRC).
ERBITUX with a type of chemotherapy called FOLFIRI (irinotecan, fluorouracil, leucovorin) was studied in a clinical trial of 1217 people with EGFR-expressing colorectal cancer that had spread (metastasized) to other parts of the body. About half of these people (608) received a cetuximab product (ERBITUX*) with FOLFIRI and the other half (609) were treated with FOLFIRI alone.
The main goal of this clinical study was to measure the length of time people lived without their cancer growing or spreading (progression-free survival).
People who received ERBITUX with FOLFIRI lived without their cancer growing or spreading for 8.9 months compared to 8.1 months with FOLFIRI alone. Additional goals of the study were to find out how many people had their tumors shrink or disappear (overall response rate), and also to measure how long people survived overall. At the final analysis, 46% of people who received ERBITUX with FOLFIRI had their tumors shrink compared to 38% of patients treated with FOLFIRI alone. Overall survival in people who received ERBITUX with FOLFIRI was 19.6 months compared to 18.5 months, which was not significantly different.
The original study included patients regardless of whether the patient tested positive for changes (mutations) in a gene called KRAS, or if the results of these tests were unknown. While this study was going on, it became known that ERBITUX may not work for people with KRAS mutations. Because of this new information, the original study results were reexamined to see how well ERBITUX with FOLFIRI worked in people who did not have KRAS mutations in their tumors. When there is no mutation, it is called KRAS wild-type. In this subgroup of people, 320 originally received ERBITUX with FOLFIRI and 356 were originally treated with FOLFIRI alone. Based on the results of this subgroup analysis, the FDA approved ERBITUX only in people who do not have KRAS mutations (KRAS wild-type), where the results of this test must be known.
More recently, it has been found that changes in other RAS genes may affect how ERBITUX works. ERBITUX should not be used in people who have RAS-mutant colorectal cancer or when the results of the RAS mutation tests are unknown.