Efficacy of cetuximab after treatment with oral epidermal growth factor receptor tyrosine kinase inhibitor-based chemotherapy in metastatic colorectal cancer.
OBJECTIVE
We studied the efficacy of cetuximab therapy in patients with metastatic colorectal cancer (mCRC) previously treated with an oral inhibitor of the tyrosine kinase domain of the epidermal growth factor receptor.


METHODS
We reviewed the posttrial records of 73 patients with mCRC who participated in 1 of 3 clinical trials that examined a combination of gefitinib or erlotinib with standard cytotoxic chemotherapy. Medical and pharmacy records were used to identify patients who were subsequently treated with cetuximab-based therapy. Computed tomography scans during cetuximab-based therapy were reviewed, and the clinical activity of cetuximab was assessed by response rate using Response Evaluation Criteria in Solid Tumors and progression-free survival.


RESULTS
Twenty-four patients with mCRC previously treated with gefitinib or erlotinib and combination cytotoxic chemotherapy who subsequently received cetuximab-based therapy were identified. While receiving cetuximab-based therapy, no patient experienced a partial or complete response; however, 3 patients (16% of patients with available scans for formal measurements) had a minor response, defined as a 15%-29.9% decrease in the sum of longest dimensions of target lesions, and 72% had stable disease. The progression-free survival was 5.1 months for all patients and 6 months for patients who had documented progression of disease while previously receiving gefitinib- or erlotinib-based therapy.


CONCLUSIONS
Cetuximab appears to have clinical benefit in patients with mCRC previously treated with a chemotherapy regimen that included an oral tyrosine kinase inhibitor of epidermal growth factor receptor. Whether these results apply to other cancer types is unknown but worthy of further study.
Meyerhardt
Jeffrey A
JA
Dana-Farber Cancer Institute, Brigham Women's Hospital, Boston, MA 02115, USA. jmeyerhardt@partners.org
Heseltine
Denise
D
Ogino
Shuji
S
Clark
Jeffrey W
JW
Enzinger
Peter C
PC
Ryan
David P
DP
Earle
Craig C
CC
Zhu
Andrew X
AX
Fuchs
Charles S
CS
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D061067:Antibodies, Monoclonal, Humanized; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D000068818:Cetuximab; D015179:Colorectal Neoplasms / Q000473:pathology*; D018572:Disease-Free Survival; D066246:ErbB Receptors / Q000037:antagonists & inhibitors; D000069347:Erlotinib Hydrochloride; D005260:Female; D000077156:Gefitinib; D006801:Humans; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis / Q000188:drug therapy; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors*; D011799:Quinazolines / Q000008:administration & dosage*
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D011799:Quinazolines; D000069347:Erlotinib Hydrochloride; D066246:ErbB Receptors; D011505:Protein-Tyrosine Kinases; D000068818:Cetuximab; D000077156:Gefitinib