Cobas® 4800 BRAF V600 Mutation Test is a CE-marked and FDA-approved in vitro diagnostic assay used to detect metastatic melanoma patients eligible for treatment with BRAF inhibitors. The aim of the study is to compare the performance of two additional commercial kits to assess BRAF mutations in this context
A total of 247 Metastatic melanoma specimens were tested for BRAF V600 mutations at three laboratories (Vall d´Hebron, 12 de Octubre and Virgen Macarena Hospitals) with the COBAS® BRAF V600 V1 (Roche), Idylla BRAF (Biocartis) and COBAS® BRAF/NRAS V2 (Roche) kits. Overall (OPA) Positive (PPA) and Negative (NPA) percent agreements were determined between the cobas V1 test and the other assays. We also analyzed the sensitivity and specificity of each assay used in this study
BRAF mutations were detected in 35.2% (87/247), 44.5% (110/247) and 42.9% (106/247) of samples by COBAS® BRAF V600 V1, Idylla and COBAS V2 kits respectively. Similar ratios of invalid results were observed in the 3 different technologies (1.2%, 1.6% and 1.6% respectively). Comparing COBAS V1 with other methods we obtained OPA 90%, PPA 79.6% and NPA 99.2% by Idylla and OPA 90%, PPA 80.3% and NPA 98.5% by COBAS V2 test. Finally, Idylla vs COBAS V2 showed OPA 96%, PPA 95.4% and NPA 97%. Sensitivity and Specificity for each assay in this global comparison were also calculated showing [82.8-100] by COBAS V1, [99-97.8] by Idylla and [98.1-97.8] by COBAS V2. Additionally, COBAS V2 test detected other BRAF non-V600 mutations (2 K601E and 1 G466A/V or G469A/R/V) and also NRAS mutations (2 NRAS G12X, 2 NRAS G13X and 41NRAS Q61X).
Both methodologies COBAS V2 and Idylla have a good performance to detect BRAF V600 mutations in metastatic melanoma samples with a high concordance between them. Both techniques compared with COBAS V1 detect more mutant BRAF V600 cases with High Sensitivity and Specificity. Finally, COBAS V2 detects more mutation out of V600 in BRAF and NRAS genes that allow managing those patients for potential different therapies.
Vall d´Hebron Institute Research
Has not received any funding
F. Garcia Verdes-Montenegro and M. Ulrech: Employee of Roche-Farma. All authors have declared no conflicts of interest.