Open-label phase III trial of panitumumab plus best supportive care compared with best supportive care alone in patients with chemotherapy-refractory metastatic colorectal cancer.
OBJECTIVE
Panitumumab is a fully human monoclonal antibody directed against the epidermal growth factor receptor (EGFR). We compared the activity of panitumumab plus best supportive care (BSC) to that of BSC alone in patients with metastatic colorectal cancer who had progressed after standard chemotherapy.


METHODS
We randomly assigned 463 patients with 1% or more EGFR tumor cell membrane staining, measurable disease, and radiologic documentation of disease progression during or within 6 months of most recent chemotherapy to panitumumab 6 mg/kg every 2 weeks plus BSC (n = 231) or BSC alone (n = 232). Tumor assessments by blinded central review were scheduled from week 8 until disease progression. The primary end point was progression-free survival (PFS). Secondary end points included objective response, overall survival (OS), and safety. BSC patients who progressed could receive panitumumab in a cross-over study.


RESULTS
Panitumumab significantly prolonged PFS (hazard ratio [HR], 0.54; 95% CI, 0.44 to 0.66, [P < .0001]). Median PFS time was 8 weeks (95% CI, 7.9 to 8.4) for panitumumab and 7.3 weeks (95% CI, 7.1 to 7.7) for BSC. Mean (standard error) PFS time was 13.8 (0.8) weeks for panitumumab and 8.5 (0.5) weeks for BSC. Objective response rates also favored panitumumab over BSC; after a 12-month minimum follow-up, response rates were 10% for panitumumab and 0% for BSC (P < .0001). No difference was observed in OS (HR, 1.00; 95% CI, 0.82 to 1.22), which was confounded by similar activity of panitumumab after 76% of BSC patients entered the cross-over study. Panitumumab was well tolerated. Skin toxicities, hypomagnesaemia, and diarrhea were the most common toxicities observed. No patients had grade 3/4 infusion reactions.


CONCLUSIONS
Panitumumab significantly improved PFS with manageable toxicity in patients with chemorefractory colorectal cancer.
Van Cutsem
Eric
E
Digestive Oncology Unit, University Hospital Gasthuisberg, Leuven, Belgium. eric.vancutsem@uz.kuleuven.ac.be
Peeters
Marc
M
Siena
Salvatore
S
Humblet
Yves
Y
Hendlisz
Alain
A
Neyns
Bart
B
Canon
Jean-Luc
JL
Van Laethem
Jean-Luc
JL
Maurel
Joan
J
Richardson
Gary
G
Wolf
Michael
M
Amado
Rafael G
RG
D000368:Aged; D000911:Antibodies, Monoclonal / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use*; D000970:Antineoplastic Agents / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use*; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000451:nursing / Q000473:pathology; D018572:Disease-Free Survival; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000378:metabolism; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D000077544:Panitumumab
D000911:Antibodies, Monoclonal; D000970:Antineoplastic Agents; D000077544:Panitumumab; D066246:ErbB Receptors