BRAF mutation testing with a novel, rapid, fully automated molecular diagnostics prototype platform.

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11086 Background: Mutations in the BRAF gene provide actionable targets for cancer therapy in melanoma and other tumor types. Novel, fast, and accurate diagnostic systems are needed for further implementation of personalized therapy. Methods: The molecular diagnostics (MDx) prototype platform (Biocartis, Mechelen, Belgium) is a fully integrated real-time PCR-based system with high sensitivity (1% mutant in wild-type [wt] background) and fast turnaround time (< 90 minutes), which requires no sample preparation and <2 min hands-on time. Archival formalin-fixed paraffin-embedded tumor samples (1 to 5 shavings of 10 µm) from patients (pts) with advanced cancers previously tested for V600 BRAF mutations in a CLIA-certified Molecular Diagnostic Laboratory (PCR-based sequencing or Sequenom MassARRAY) were tested for BRAF V600 mutations using the MDx prototype platform. Concordance between methods and treatment outcomes with BRAF/MEK inhibitors were analyzed. Results: Forty-seven pts (melanoma, n=26; colorectal, n=8; papillary thyroid, n=3; other cancers, n=10) with available tissue and CLIA laboratory BRAF results were selected (BRAF V600 mutant, n=37; BRAF V600 wt, n=10). Of the 40 pts for whom the same tissue block was used for MDx and CLIA, BRAF status was concordant in 38 (95%; kappa 0.87; 95% CI 0.69-1.05) of them. BRAF status by MDx was discordant with CLIA in 3 of 47 cases (mutant by CLIA, but not MDx); one discrepant case contained a different mutation subtype (resp. V600E vs. V600K/R), and in another case different tissue blocks were used for MDx vs. CLIA testing. Of 34 pts with BRAF mutations detected by MDx, 28 were treated on protocols (on the basis of the CLIA results) with BRAF/MEK inhibitors and 8 (29%) had a partial (n=7) or complete response (n=1). Of interest, 1 pt with prostate cancer (V600E by CLIA, wt by MDx) received a BRAF/MEK inhibitor and did not respond. Detailed patient characteristics, mutation types and discrepancy analysis will be presented. Conclusions: The BRAF V600 mutation MDx prototype assay is a fast (turn-around time about 1.5 hours) and simple (<2 minutes hands-on time) test to determine BRAF mutation status with 95% concordance with CLIA laboratory if identical tissue blocks are used.