CRCdx® RAS Mutation Detection Kit

e CRCdx® RAS Mutation Detection Kit is a real-time PCR in vitro diagnostic test designed to detect 35 variants of KRAS and NRAS exon 2, 3, and 4 somatic mutations in genomic DNA extracted from formalin-fixed, paraffin-embedded (FFPE) colorectal cancer (CRC) tissue samples. As a companion diagnostic (CDx), it helps identify CRC patients who may benefit from anti-EGFR therapy, specifically Vectibix® (panitumumab), by confirming the absence of RAS mutations. This targeted approach ensures that only patients with wild-type RAS genes receive treatment, aligning with approved therapeutic guidelines and improving patient outcomes.

CRCdx® is designed with high sensitivity and specificity to accurately detect KRAS and NRAS mutations, even in samples with low tumor DNA content. By utilizing allele-specific oligonucleotide primers and fluorescent hydrolysis probes, the assay can precisely differentiate between wildtype and mutated alleles, minimizing false positives and false negatives. This high level of accuracy ensures that clinicians receive reliable results, enabling them to make well-informed treatment decisions.

The RAS Mutation Screening Panel identifies the presence of the mutations in a total of 8 reactions (groups) per sample. The test does not distinguish between mutations within each group.

Below is a list of mutations detected by this kit.

¹ My Cancer Genome; www.mycancergenome.org (Colorectal Carcinoma, Colorectal Adenocarcinoma)

Concordance Test

The safety and effectiveness of the CRCdx® RAS Mutation Detection Kit were evaluated in an external concordance study to demonstrate non-inferiority to the FDA-approved Praxis® Extended RAS Panel for validating its use as a companion diagnostic for panitumumab (Vectibix®). The study tested 398 archived CRC patient FFPE tissue samples with both CRCdx® and Praxis®, assessing mutation-level agreement. Concordance analysis showed PPA = 99.6%, NPA = 92%, and OPA = 96.2%, confirming CRCdx® as a reliable alternative for identifying RAS mutation status to guide Vectibix® treatment decisions.

Precision Test

The Precision of the CRCdx® RAS Mutation Detection Kit was evaluated using 16 mutant CRC FFPE specimens, 7 mutant cell lines, and 12 synthetic mutant gene blocks, all diluted to 1.5X or 3X LoD and tested across three device lots at three external sites by two operators per site. Samples were extracted using Promega’s Maxwell® CSC FFPE DNA Extraction Kit, diluted in wildtype CRC FFPE DNA, and analyzed via NGS. Controls were included in each run, with data analyzed by EntroGen using EPAS™. The study achieved a 90.0% first-pass rate (1,166/1,296), with 9.3% of samples requiring re-runs due to control failures or user errors. A total of 2,571 (2499/2499 mutant and 72/72 wildtype samples) sample replicates were analyzed, achieving a 100.0% correct call rate across all variables.