The US Food and Drug Administration (FDA) has approved a new indication for panitumumab (Vectibix, Amgen), specifically use in combination with the FOLFOX (fluorouracil plus leucovorin and oxaliplatin) chemotherapy regimen in the first-line treatment of patients with wild-type KRAS (exon 2 in codons 12 or 13) metastatic colorectal cancer (mCRC).
At the same time, the FDA approved a companion diagnostic test, the therascreen KRAS test (Qiagen), to identify patients suitable for this treatment. The drug should not be used in patients with KRAS-mutant mCRC or in whom KRAS mutation status is unknown.
The agency also granted full approval for panitumumab, which converts the accelerated approval that it was granted in 2006, although the labelling was modified to include information on KRAS mutations in 2009. The drug was already approved for use as monotherapy following disease progression after prior treatment with fluoropyrimidine-, oxaliplatin-, and irinotecan-containing chemotherapy.
Approval of the new indication is based on results from the phase 3 clinical trials PRIME and ASPECCT, the manufacturer noted in a press release.
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, Lilly/Bristol-Myers Squibb) as a single agent for mCRC in patients with wild-type KRAS tumors who had not responded to chemotherapy.
The therascreen KRAS diagnostic kit is also approved for use with cetuximab, which is approved for use in combination with FOLFIRI (irinotecan, 5-fluorouracil, and leucovorin) in patients with wild-type KRAS mCRC.
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Cite this: FDA Approves Panitumumab for Use With FOLFOX in mCRC - Medscape - May 26, 2014.