4672 - mCRC gene profiling using the Idylla platform

Background

KRAS, NRAS and BRAF mutation testing for metastatic colorectal cancer (mCRC) is essential to guide treatment and prognostication. Multiple gene profiling assays are available, each with differing tumour sample size/quality requirements and turnaround time (TAT). Many UK hospitals send samples to off-site labs for profiling. A rapid TAT is desirable to plan appropriate chemotherapy +/- biologics from cycle one, as well as providing certainty and satisfaction for patients and clinicians.

Methods

This study was conducted at 2 UK tertiary cancer centres (University College London Hospital and Mount Vernon Hospital), comparing a pathway where gene profiling of mCRC was performed off-site using an NGS platform versus on-site testing using the Idylla platform (Biocartis, Mechelen, Belgium). Up to 50 patients were included in each group with 8 of the Idylla tests being used for samples that had failed with the NGS platform.

Results

Mutational profiling results for the whole cohort that were successfully tested (n = 84) showed 26% (22/84) were wildtype for KRAS/NRAS/BRAF, 62% (52/84) KRAS mutated, 2% (2/84) NRAS mutated, 10% (8/84) BRAF mutated. The median TAT in days (median, interquartile range (IQR)) of the on-site Idylla pathway was shorter than the off-site NGS pathway (4, 1 - 6 vs. 15, 13-17; p = <0.0001). In the off-site group median time from request to receipt of sample was 3 days (IQR 2 - 5) and median time from receipt to result was 10 days (IQR 9 - 13). Test failure rate was significantly higher with the NGS test (30%, 15/50) compared to the Idylla test (2%, 1/50) (p = 0.0001). 8 samples that had failed testing with the NGS platform, due to insufficient/low quality of sample, were all successfully tested with the Idylla platform.

Conclusions

For gene profiling of mCRC, on-site testing with the Idylla platform significantly shortened the TAT, lowered failure rate and was able to test more sub-optimal samples compared to off-site NGS testing. Updated results integrating these data with tumour location, MMR status and treatment outcomes will be presented at ESMO 2019.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Biocartis provided the Idylla test kits for this study without charge.

Disclosure

N. Bhuva: Honoraria (self), supported in attending international meetings: Amgen; Honoraria (self), supported in attending international meetings: Bristol-Myers Squibb. K. Shiu: Honoraria (self), Advisory / Consultancy, supported in attending lectures and conferences: Roche; Honoraria (self), Advisory / Consultancy, supported in attending lectures and conferences: Merck Group; Honoraria (self), Advisory / Consultancy, supported in attending lectures and conferences: Servier; Honoraria (self), Advisory / Consultancy, supported in attending lectures and conferences: Guardant Health. All other authors have declared no conflicts of interest.