Patients with interleukin 28B CC genotype had a slightly better response to hepatitis C treatment with pegylated interferon, ribavirin and telaprevir than those with the CT or TT genotypes in a recent study.
Researchers performed genetic testing on 527 patients with hepatitis C genotype 1 to detect polymorphisms of the IL28B gene. All participants had been enrolled in the REALIZE study, in which patients randomly were assigned either placebo (n=105) or 750 mg telaprevir every 8 hours for 12 weeks (n=422), in addition to 180 mcg weekly of pegylated interferon alfa-2a and between 1,000 mg and 1,200 mg ribavirin daily for 48 weeks.
Sustained virologic response (SVR) occurred more frequently among treated patients compared with placebo recipients regardless of genotype. The highest rates were observed among those with CC genotype: 79% of all treated patients achieved SVR compared with 29% of controls. SVR rates were 60% vs. 16% with genotype CT patients, and 61% vs. 13% with genotype TT patients. Among prior null and partial responders who received telaprevir, those with CC genotype also had a slightly higher rate of SVR vs. other genotypes. Multivariate analysis indicated no impact of IL28B genotype on SVR (P>.16 for all comparisons between the three genotypes).
Rapid virologic response (RVR) for telaprevir recipients was slightly higher for those with CC genotype, both overall and among null or partial responders. There also was a trend toward fewer relapses or virologic breakthrough during treatment with telaprevir for CC genotype.
“This retrospective subanalysis … suggests that IL28B genotype may have limited utility in guiding the use of this therapeutic regimen in this patient population,” the researchers wrote. “It is therefore likely other factors have a greater effect in determining response to telaprevir-based therapy in this population. This finding underscores the need for continued efforts to identify predictive biomarkers that will be clinically useful for managing patients with HCV disease in the era of [direct-acting antivirals], particularly in the treatment-experienced population.”
Disclosure: See the study for a full list of relevant disclosures.