The U.S. Food and Drug Administration (FDA) has approved panitumumab (Vectibix) for use in combination with FOLFOX (fluorouracil, leucovorin, oxaliplatin) as first-line treatment in patients with wild-type KRAS (exon 2) metastatic colorectal cancer.
This approval converts the accelerated monotherapy approval granted in 2006 to a full approval. Panitumumab was previously approved by the FDA as a monotherapy for patients with EGFR-expressing metastatic colorectal cancer after disease progression and prior treatment with fluoropyrimidine-, oxaliplatin-, and irinotecan-containing chemotherapy. The agent is not indicated for the treatment of patients with KRAS-mutant metastatic colorectal cancer or for whom KRAS mutation status is unknown.
The FDA has also approved the therascreen KRAS test as a companion diagnostic to guide use of panitumumab in the treatment of metastatic colorectal cancer.
Phase III Studies
The approval is based on results from the phase III PRIME and ASPECCT trials. The PRIME study showed that patients with wild-type KRAS tumors in exon 2 achieved statistically significant improvement in progression-free survival with panitumumab and FOLFOX vs FOLFOX alone (9.6 vs 8.0 months, P = .02) and a significant 4.4-month improvement in overall survival vs FOLFOX alone (23.8 vs 19.4 months).
The ASPECCT study met its primary endpoint of noninferiority for improving overall survival in patients taking panitumumab vs cetuximab (Erbitux) as a single agent for the treatment of metastatic colorectal cancer in patients with wild-type KRAS tumors who have not responded to chemotherapy.
“[Panitumumab] is now the first approved biologic to show a significant survival benefit when combined with FOLFOX as a first-line treatment,” said Lee S. Schwartzberg, MD, Medical Director of The West Clinic, Memphis. “[Panitumumab] has shown a significant benefit to patients with wild-type KRAS metastatic colorectal cancer when used with FOLFOX, which gives us a valuable new treatment option as we help patients fight this devastating disease.”
Colorectal cancer is the third most common cancer found in both men and women in the United States, and is the second leading cause of cancer deaths. ■