HEPATITIS C NEWS
HCV Protease Inhibitor Boceprevir Demonstrates Durable Sustained Response with No Late Relapse
April 16, 2010
Sustained virological response (SVR) to hepatitis C therapy -- defined as continued undetectable HCV viral load 6 months after completion of treatment -- is generally considered a "cure," though a small proportion of patients treated with interferon-based therapy may experience late viral relapse after this point.
J. Vierling from St. Luke's Episcopal Hospital in Houston and colleagues looked at long-term outcomes among participants who received boceprevir plus pegylated interferon alfa-2b (PegIntron), with or without ribavirin, in previous Phase 2/3 clinical trials.
The researchers analyzed blood samples from 604 patients, including formerly treatment-naive individuals and those who did not respond to a prior course of pegylated interferon plus ribavirin, after up to 3 years post-therapy. Most participants (nearly 90%) were white and the average was about 50 years.
The extended follow-up cohort consisted of 520 participants from the SPRINT-1 treatment-naive trial, of whom 269 patients achieved SVR and 104 were treatment failures. Another 357 patients were from Study PO3659 looking at prior non-responders, of whom 21 achieved SVR and 205 were treatment failures. In addition, 5 patients were included from another prior non-responder study, PO4887.
HCV RNA was detected using the Roche Taqman assay with a lower limit of detection of 29 IU/mL and resistance mutations were detected by population sequencing of the HCV NS3 protease region (codons 1-181).
Results
Among the 290 patients who achieved SVR, no cases of late relapse were confirmed. |
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1 person was confirmed to have been re-infected with HCV based on genotype/subtype sequence. |
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29 patients (5%) experienced serious adverse events during extended follow-up, similar to those previously described during initial follow-up. |
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A total of 18 boceprevir resistance mutations were identified, including: |
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People with the V36M mutation experienced faster reversion to wild-type (non-mutated) virus after treatment completion compared to those with T54S or R155K mutations. |
"SVR following boceprevir combination therapy was durable up to 2 years after end of treatment," the study investigators concluded. "No latent serious adverse events or laboratory abnormalities related to prior treatment were observed over follow-up period."
"Specific resistance mutations to boceprevir declined at different rates, V36M declined fastest; T54S and R155K declined at similar rates," they continued. "Variation in the rate of mutational decline likely reflects the relative fitness of the mutants."
Advanced Liver Therapies/St. Luke's Episcopal Hospital, Houston, T; Merck Research Laboratories, Kenilworth, NJ; Alamo Medical Research, San Antonio, TX; Mount Vernon Endoscopy Center, Alexandria, VA; Henry Ford Hospitals, Detroit, MI; Indianapolis Gastroenterology Research Foundation, Indianapolis, IN; South Florida Center of Gastroenterology, Wellington, FL; Liver Specialists of Texas, Houston, TX; Weill Medical College of Cornell University, New York, NY; Davis Medical Center, University of California, Sacramento, C; Liver and Intestinal Research Centre, Vancouver, BC, Canada' LSU Medical Center; Louisiana State University, Shreveport, Baton Rouge, LA; Hospital Saint Joseph, Marseill, France; Hospital Vall d'Hebron, Barcelona, Spain; Digestive Disease Associates, Baltimore, MD; Kelsey Research Foundation, Houston, TX.
JM Vierling, R Ralston, EJ Lawitz, and others. Long-term outcomes following combination treatment with boceprevir plus Peg-Intron/ribavirin (P/R) in patients with chronic hepatitis C, genotype 1 (CHC-G1). 45th Annual Meeting of the European Association for the Study of the Liver (EASL 2010). Vienna , Austria . April 14-18, 2010.