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New assay may help predict progression of HCV genotype 1b

Researchers in Japan have developed a new, rapid assay system that accurately detected mutant strains in patients with hepatitis C virus genotype 1b infection, indicating it could potentially measure the progression of the infection, according to recent findings.

Kazuaki Chayama, MD, PhD, department of gastroenterology and metabolism, Institute of Biomedical and Health Sciences, Hiroshima University, and colleagues, combined nested polymerase chain reaction (PCR) and the newly designed “Invader assay” with primers and probes and found that the Y93H drug resistant mutation had a 98.9% detection rate among a cohort of 702 Japanese treatment-naive patients with HCV genotype 1b.

Kazuaki Chayama

The rapid detection system evaluated serum samples of all the patients, whom were also receiving NS5A inhibitor-based treatment for the infection. Of the patients successfully tested (n = 694), Y93H was found in 23.6% of them, which was comparable to real-time PCR, according to the release.

To determine nested PCR, the researchers used a total of 240 NS5A sequences of HCV serum from a public database to use as a guide for building a successful primer and probe design, according to the research. Three nucleotide sequences were developed for the Invader assay and each sequence corresponded to Y or H variants.

To determine the frequency of NS5A-Y93H, the researchers used ultra-deep sequencing, as well as a “wild-type hepatitis C virus-expressing plasmid” to determine the minimum detection threshold.

“Our assay system showed a much lower detection limit for Y93H than using direct sequencing, and Y93H frequencies obtained by this method correlated well with those of deep-sequencing analysis,” Chayama said in a press release.

Along with the high success rate, the analysis showed that regardless of high or low HCV titer, Y93H drug resistant mutation could be successfully detected, according to the release.

“Because the method is both sensitive and rapid, the NS5A-Y93H mutant strain detection system established in this study may provide important pre-treatment information valuable not only for treatment decisions, but also for prediction of disease progression in HCV genotype 1b patients,” the researchers wrote. – by Melinda Stevens

Disclosures: Healio.com/Hepatology was unable to confirm relevant financial disclosures at the time of publication.