Robust Performance of the Novel Research-Use-Only Idylla GeneFusion Assay Using a Diverse Set of Pathological Samples with a Proposed 1-Day Workflow for Advanced NSCLC Evaluation

SIMPLE SUMMARY: Updated international guidelines suggest NGS as the preferred procedure for NSCLC patients’ evaluation for predictive biomarkers, but NGS facilities are not available everywhere. Alternative molecular techniques are rapidly evolving, each with different characteristics and performance in terms of turn-around time, sensitivity, specificity and required personnel skills. Among these, the novel Idylla(TM) GeneFusion assay, a rapid and fully automated platform able to simultaneously detect ALK, ROS1, RET and NTRK1/2/3 and MET ex14 skipping mutations, is emerging and deserves validation as a stand-alone test for laboratories lacking NGS facilities or as an alternative option for ultra-rapid NSCLC patient profiling when time efficient NGS evaluation is not possible. ABSTRACT: A range of different techniques are available for predictive biomarker testing for non-small-cell lung cancer (NSCLC) clinical management. International guidelines suggest next-generation sequencing (NGS) as the preferred procedure, but other reverse transcriptase-polymerase chain reaction (RT-PCR)-based methods are rapidly evolving. In this study, we evaluated the reliability and accuracy of the Idylla(TM) GeneFusion assay, a rapid and fully automated platform able to simultaneously detect ALK, ROS1, RET and NTRK1/2/3 and MET ex14 skipping mutations and compared its performance with routine reference methods. The cohort included thirty-seven NSCLCs plus two parotid gland carcinomas, previously characterized for the above alterations through either IHC, FISH, RT-PCR or NGS. In 36 of 39 cases, the Idylla GeneFusion assay and the reference methods were concordant (overall agreement: 92.3%). Tumor sections stored at room temperature for up to 60 days and 17 cases older than 2 years were successfully characterized. Our results suggest that the Idylla GeneFusion assay is a reliable tool to define gene fusion status and may be a valuable stand-alone diagnostic test when time efficiency is needed or NGS is not feasible.