Vectibix (Panitumumab) Plus FOLFOX Chemotherapy Receives Regulatory Approval for Treatment of Colorectal Cancer
Combo treatment superior to FOLFOX alone
The FDA has approved Vectibix (panitumumab, Amgen) for use in combination with FOLFOX, an oxaliplatin-based chemotherapy regimen, as first-line treatment in patients with wild-type KRAS (exon 2) metastatic colorectal cancer (mCRC).
With this approval, Vectibix becomes the first biologic agent to offer a survival benefit as first-line treatment with FOLFOX, one of the most commonly used chemotherapy regimens in the first-line setting for patients with wild-type KRAS mCRC. In addition, the approval converts the FDA’s accelerated monotherapy approval to a full approval for Vectibix. The agency has also approved the therascreen KRAS RGQ PCR kit developed by Qiagen as a companion diagnostic for Vectibix.
The FDA’s approval was based on results from the PRIME and ASPECCT trials. The phase III PRIME study showed that patients with wild-type KRAS tumors in exon 2 achieved statistically significant improvements in progression-free survival with panitumumab and FOLFOX compared with FOLFOX alone (9.6 months vs. 8.0 months, respectively; P = 0.02) and a significant 4.4-month improvement in overall survival compared with FOLFOX alone (23.8 months vs. 19.4 months, respectively).
The phase III ASPECCT study met its primary endpoint of non-inferiority for improving overall survival in patients treated with panitumumab compared with those treated with cetuximab (Erbitux, Bristol-Myers Squibb/Eli Lilly) as a single agent for the treatment of mCRC in patients with wild-type KRAS tumors who did respond to chemotherapy.
Panitumumab is the first fully human anti-epidermal growth factor receptor (EGFR) antibody approved by the FDA for the treatment of mCRC. It was approved in the U.S. in September 2006 as monotherapy for patients with EGFR-expressing mCRC after disease progression after prior treatment with fluoropyrimidine-, oxaliplatin-, and irinotecan-containing chemotherapy.
The product labeling for Vectibix includes a boxed warning regarding the potential for dermatologic toxicities. Such toxicities occurred in 90% of patients and were severe (NCI–CTC grade 3 or higher) in 15% of patients receiving Vectibix monotherapy.
Determination of the KRAS mutational status in colorectal tumors using an FDA-approved test indicated for this use is necessary for the selection of patients for treatment with Vectibix. Patients with KRAS-mutant mCRC tumors receiving Vectibix in combination with FOLFOX experienced shorter overall survival compared with patients receiving FOLFOX alone.
Colorectal cancer is the third most common cancer in both men and women in the U.S., and is the second leading cause of cancer deaths.
Source: Amgen; May 23, 2014.