On June 29, 2017, the U.S. Food and Drug Administration granted marketing approval to the Praxis Extended RAS Panel (Illumina, Inc.), a next generation sequencing (NGS) test to detect certain genetic mutations in RAS genes in tumor samples of patients with metastatic colorectal cancer (mCRC). The test is used to aid in the identification of patients who may be eligible for treatment with panitumumab (VECTIBIX, Amgen, Inc.).
This is the first FDA-approved NGS test that can detect multiple RAS gene mutations for colorectal cancer in a single test.
The Praxis Extended RAS Panel detects the presence of 56 specific mutations in RAS genes (KRAS exons 2, 3, and 4 and NRAS exons 2, 3, and 4) in the tumor tissue of patients with mCRC. If the Praxis Extended RAS Panel result indicates that a mutation is present in the colorectal cancer tissue, then panitumumab is not recommended. If the Praxis Extended RAS Panel does not detect a mutation (presumed to be RAS mutation-negative), then panitumumab may be an appropriate treatment.
The safety and effectiveness of the Praxis Extended RAS Panel was studied retrospectively using available specimens from mCRC patients enrolled in a multi-center clinical trial that evaluated panitumumab plus FOLFOX to FOLFOX alone. Progression-free survival and overall survival in wild-type RAS patients demonstrated that the efficacy of panitumumab in patients whose tumors do not have a KRAS or NRAS mutation is supported. Analytical validation demonstrated that the panel performs consistently and accurately in the detection of the select KRAS and NRAS mutations in mCRC patients.
Panitumumab’ s product labeling has been modified to align the indication for panitumumab and intended use for the Praxis Extended RAS Panel, stating that panitumumab is indicated in first-line therapy in combination with FOLFOX for patients with wild-type RAS (defined as wild-type in both KRAS and NRAS as determined by an FDA-approved test for this use) metastatic colorectal cancer. Vectibix is also indicated as monotherapy for patients with wild-type RAS metastatic CRC following disease progression after prior treatment with fluoropyrimidine, oxaliplatin, and irinotecan-containing chemotherapy.
Instructions for use of the Praxis Extended RAS Panel is available at: https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfPMA/pma.cfm?id=P160038.
Full prescribing information for panitumumab is available at: http://www.accessdata.fda.gov/drugsatfda_docs/label/2017/125147s207lbl.pdf.
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