In terms of cost, throughput and reliability, the development of next-generation technology has revolutionised genetic sequencing when it comes to the identification of disease-causing mutations. Dr Andreas Görtz, Vela Diagnostics’ European managing director, explains the sense behind employing the company’s Sentosa sequencing technology.

Over the past few years, next-generation sequencing (NGS) has become a valuable method for the identification of genetic variations and a proven alternative to classical Sanger sequencing. NGS offers unprecedented throughput in comparison with conventional sequencing methods, combined with a significant overall reduction in cost.

The identification of disease-causing mutations in cancer by technologies such as NGS has led to the discovery of a variety of novel drug targets, and triggered the development of a new generation of highly specific and effective anti-cancer drugs. Due to its sequencing power, ability to multiplex samples via tagging with molecular barcodes, and reducing the time to result and cost, NGS has become a promising new technology for clinical diagnostics.

On the right track with automation

Molecular diagnostics requires a variety of tightly defined quality criteria in order to ensure that a test can be used in a safe, reliable and reproducible manner while also controlling cost. Conventional diagnostic methods are therefore often driven by a high degree of automation, sample-tracking capability, as well as user-friendly and reproducible IT solutions for calling results.

Until recently, NGS was perceived as having only limited use for routine diagnostic applications due to a lack of automation and sample tracking, the generation of large amounts of data without present clinical value, and the requirement of advanced molecular biology and informatics skills.

In September 2014, Vela Diagnostics launched the Sentosa® NGS System*, specifically developed for the needs of routine molecular diagnostics applications. The Sentosa sequencing technology uses massively parallel sequencing powered by semiconductor chips. The isolation of nucleic acids from valuable and scarce sample material is automated and requires minimal amounts of plasma/serum or FFPE sections.

Automation of library and template preparation keeps manual intervention to a minimum, and thereby increases the reproducibility and robustness of the process. In order to ensure that patient samples are not mixed up during the process, the Sentosa system employs sample-tracking capability via barcode scanning and sample ID download from a laboratory information system. In order to increase throughput and decrease cost, clinical samples are tagged with a molecular barcode enabling multiplexing of up to 16 samples in each run.

Sequencing occurs on the Sentosa SQ bench-top system, which generates highly accurate data sets that are automatically analysed and quality controlled by the Sentosa Reporter software. The user is provided with a comprehensive report listing the detected genetic variants as well as the quality score. Beyond normal computer knowledge, no informatics skills are required. The total time from sample to result is 2.5 days, allowing the completion of multiple runs each week.

An extended run

With its melanoma panel, Vela Diagnostics launched the first CE-IVD test for NGS oncology testing worldwide*.

The Sentosa Melanoma test uses 5ng of DNA and allows sequencing of a set of ten clinically relevant gene regions, including disease-relevant exons in BRAF and NRAS with coverage of 1,000×. In total, 127 potential mutations are analysed. In one sequencing run, up to seven clinical samples are sequenced in parallel, and the addition of a system control ensures the sequencing run quality.

Sentosa Reporter automatically analyses the data and provides a report for the presence of the targeted mutations in each of the seven samples, making the entire process incredibly convenient for the user. More tests, such as a colon and NSCLC panel, as well as a HCV genotyping test, are planned for launch in late 2014. With the Sentosa automated system from Vela, next-generation sequencing has arrived in the molecular diagnostics laboratory.

* Product availability is country-dependent, not available in the US.