CROI 2012: PSI-7977/ribavirin combo achieved rapid response in HCV genotype-1

Posted on InfectiousDiseaseNews.com March 6, 2012

SEATTLE — An interferon-free, experimental nucleotide analogue, PSI-7977, plus ribavirin for 12 weeks achieved rapid on-treatment response in hepatitis C virus genotype-1 patients and was well tolerated in this population, according to presenter Edward Gane, MD.

Gane, a hepatologist at Auckland City Hospital in New Zealand and principal investigator for the ELECTRON study, presented findings from a phase 2, multi-arm study aiming to assess the uridine nucleotide analogue, PSI-7977, combined with ribavirin currently in phase 3 development.

“Results on genotype-2 and genotype-3 patients were presented at the Liver meeting last fall, which demonstrated 100% rapid virologic response rates with interferon-free PSI-7977 plus ribavirin,” Gane said during a press conference today. “Following these results, we enrolled additional patients who were genotype-1 treatment-naive and null responders.”

For the current study, Gane and colleagues assigned 400 mg PSI-7977 plus ribavirin to 10 null responders and 25 treatment-naive patients with HCV genotype-1. Researchers compared early on-treatment data with data from treatment-naive patients with HCV genotype-2 and genotype-3 included in the ELECTRON study.

“Treatment-naive patients just completed treatment,” Gane said. “Therefore, results will not be available until next quarter and will be presented at the Liver meeting in Europe.”

However, overall data, thus far, indicate that patients achieved rapid treatment response, and among all participants, HCV RNA remained undetectable at 4 weeks and throughout the treatment regimen.

Of the nine null patients who have reached the 4-week treatment time point, eight patients relapsed. The one responder was a young, white woman who had the IL28 gene, a favorable predictor for response to interferon-based treatment, according to Gane.

“The majority of null responders have relapsed post-treatment. Further treatment options in this very difficult to treat group will either be longer duration of PSI-7977 plus ribavirin or the addition of another direct-acting antiviral,” he said.

For more information:

• Gane E. #54LB. Presented at: 19th Conference on Retroviruses and Opportunistic Infections; March 5-8, 2012; Seattle.

Disclosure: The researchers report no relevant financial disclosures.

Source