Abstract 2276: Performance and cost comparison of circulating tumor DNA detection platforms
Authors: Vessies Daan C. , Greuter Marjolein J. , Rooijen Karlijn L. van , Linders Theodora C. , Lanfermeijer Mirthe , Ramkisoensing Kalpana L. , Grijseels Flore E. , Doorn Boris van , Meijer Gerrit A. , Koopman Miriam , Coupé Veerle M. , Vink Geraldine R. , Fijneman Remond J. , Broek Daan van den 
Published: August 2019

Abstract
Purpose
The field of circulating cell free DNA (cfDNA) testing is quickly developing. Multiple platforms to detect hotspot mutations in ctDNA are available, including Bio-Rad droplet digital PCR (ddPCR), BioCartis Idylla, Roche COBAS z480 and Sysmex BEAMing. These platforms vary in the amount of plasma required, the method of ctDNA isolation, the number of hotspots analyzed, and the costs per sample. These factors can impact the applicability of a specific platform in the analysis of ctDNA.
In this study we compared these platforms in terms of sensitivity and total costs per sample.
Methods
The platform comparison was performed as follows:
1. Plasma from six metastatic colorectal cancer (mCRC) patients with known tissue KRAS mutation status was analyzed according to the manufacturers’ protocols.
2. Sensitivity was tested using six constructed reference samples with seven KRAS hotspot mutations at various total input (10ng, 50ng) and mutant allele frequencies (0%, 0.04%, 0.50%); each in four replicates.
3. Twelve mCRC patients were analyzed using equal amounts of ctDNA for each platform.
4. Total costs per sample were evaluated, including costs for consumables, technician hands-on time, equipment and maintenance.
Results
1. In six mCRC samples BEAMing (3ml plasma) detected 5/6 mutations, ddPCR and Idylla (both 1ml plasma) 4/6 mutations and COBAS z480 (2ml plasma) 3/6 mutations.
2. In constructed reference samples ddPCR (65%) and BEAMing (46%) yielded the highest sensitivity. With 10ng input BEAMing and COBAS z480 produced “Too little DNA” errors in 60% and 100% of cases, respectively.
3. In twelve mCRC samples, eight had more than 10ng ctDNA and four had less. All platforms were fully concordant for samples with more than 10ng input. Detection rate across twelve samples: Idylla detected 7/11 detectable mutations, COBAS z480 and BEAMing both detected 5/11, ddPCR detected 4/10.
4. BEAMing has the highest cost per sample (€486-€821) whereas ddPCR has the lowest cost per sample (€39-€298).
Conclusions
A direct comparison of ctDNA mutation detection platforms is complex and should take into account the differences in input and output specifications of the platforms.
Factors such as complexity of analysis (Idylla is a low complexity platform, whereas BEAMing requires more specialized training), total costs (varying from ddPCR to BEAMing), sensitivity (ddPCR and BEAMing yielded the highest sensitivity) and the number of mutations evaluated vary greatly between the platforms. All these factors influence ctDNA analysis and will have to be considered when choosing a specific platform for a specific (clinical) question, or when comparing results between studies.
Our data provide insight in the comparative performance of four commercial ctDNA analysis platforms, allowing future users to make an informed decision regarding a platform.
Acknowledgement
Powered by Health~Holland, Top Sector Life Sciences & Health, grant LSHM16047-H005.
Citation Format: Daan C. Vessies, Marjolein J. Greuter, Karlijn L. van Rooijen, Theodora C. Linders, Mirthe Lanfermeijer, Kalpana L. Ramkisoensing, Flore E. Grijseels, Boris van Doorn, Gerrit A. Meijer, Miriam Koopman, Veerle M. Coupé, Geraldine R. Vink, Remond J. Fijneman, Daan van den Broek. Performance and cost comparison of circulating tumor DNA detection platforms [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2276.