236P - INTENT study: Assessment of fast track (FT) panel with IHC, RT-PCR and FISH as an alternative or rescue to NGS panel testing failure in NSCLC

Background

Around 30% of NSCLC samples are ineligible for NSG due to low amounts of tumor cells or DNA/RNA (quantity)metrics. In this scenario, the feasibility of specific tests (RT-PCR, IHC or FISH) for the main therapeutic targets, exclusively or in parallel to the NGS panel, could avoid a new invasive procedure and decrease the turnaround time (TAT) for diagnosis.

Methods

Samples of NSCLC patients, candidates for NGS, were prospectively included in the study to carry out parallel non-NGS tests for the main therapeutic targets of NSCLC with drugs approved by Brazilian regulatory agency (FT containing IHC for ALK and pan-TRK, FISH for ROS1, RT-PCR for EGFR and BRAF). The primary endpoint was the feasibility rate of the FT panel in cases deemed technically unsuitable for NGS or cases of sequencing failure. Feasibility would be achieved if >50% of the FT could give a partial result (with at least one positive test) or a full negative result. All tests were performed at OC Precision Medicine (Sao Paulo, Brazil). The NGS assay used ARCHER^TMtechnology (DNA/RNA sequencing of 180 genes). The study was approved by the local IRB and all patients provided consent before enrollment.

Results

Of 211 samples included in the study, 143 were considered unsuitable for NGS (50.4%) or failed DNA or RNA seq (49.6%). The primary endpoint was achieved with a FT feasibility rate of 51% (46 with full negative result and 27 with at least one positive result). DNA seq failure was 16% and RNA seq failure was 52%, mainly due to pre-analytic parameters. The first pass rate for FT tests varied from 63% (EGFR RT-PCR) to 100% (pan-TRK IHC). Inter-reader agreement was 100%. The median TAT for FT was 14 days and for NGS it was 20 days.

Conclusions

With one-third of samples deemed ineligible for NGS and a significant proportion of sequencing failures, primarily attributable to pre-analytical issues, it underscores the imperative for pathologists to play a pivotal role in molecular testing decisions trees. Especially for samples exhibiting limited cellularity, implementing a non-NGS panel either exclusively or in parallel to the NGS panel proved to be a better strategy, retrieving relevant molecular information in more than half of cases.

Legal entity responsible for the study

Oncoclínicas, Brazil Roche Tissue Diagnostics.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.