Merck's Combo Hepatitis C Treatment Effective in Drug Users

Study results presented at the 2015 Liver Meeting suggest that the investigational once-daily tablet elbasvir/grazoprevir can safely and effectively treat Hepatitis C virus (HCV) in intravenous drug users, considered to be “difficult” cases, in part due to the risk of re-infection.

The findings are important, because many states require that HCV patients prove that they abstain from drug use before they are eligible for coverage through Medicaid. Studies have shown that nearly half of young adults who have ever injected narcotics--including prescription painkillers and heroin--have HCV. To date, however, few large studies have looked at the effectiveness of new oral therapies for HCV in treating IV drug users. A U.S. government study found that nearly half of young people who have ever injected narcotics like prescription painkillers or heroin have the virus, which spreads easily through needles. And because these patients are likely to continue to use IV drugs, it is often considered a major obstacle to adherence to HCV treatment.

In the current Phase 3 randomized, double-blind, placebo-controlled study, C-EDGE CO-STAR, IV drug users with HCV genotypes 1, 4, and 6 were given 50mg or 100mg of elbasvir/grazoprevir (manufactured by Merck) for 12 weeks. Patients were also receiving treatment for narcotic dependence. Ninety-five percent (189/198) of patients treated with elbasvir/grazoprevir for 12 weeks in the pre-specified primary efficacy analysis population achieved sustained virologic response 12 weeks after the completion of treatment. Adherence to treatment was high, with 97% of patients taking at least 95% of their study medication over the 12 weeks of therapy.

The study randomized 301 patients to one of two study arms: an immediate treatment group (ITG) that received elbasvir/grazoprevir (blinded) for 12 weeks (n=201), and a deferred treatment group (DTG) that received 12 weeks of placebo (control arm) followed by a four-week follow-up period, and then elbasvir/grazoprevir (open-label) for 12 weeks (n=100).

Three patients discontinued treatment for reasons unrelated to study drug, and 5 cleared their baseline infection but subsequently acquired a new infection. The highest success of the medication was in patients with genotype 1 HCV, where 100% (11/11) achieved SVR. By contrast, 60% of genotype 6 patients (3/5) achieved SVR after 12 weeks. The use of non-prescribed drugs, such as cocaine and/or amphetamines, was observed in 59 percent of patients at baseline and remained steady throughout the trial; however, adherence to treatment with elbasvir/grazoprevir was high.

Earlier this year, the Food and Drug Administration granted elbasvir/grazoprevir breakthrough therapy status for the treatment of patients with chronic HCV genotype 1 infection with end stage renal disease on hemodialysis and for the treatment of patients with chronic HCV genotype 4 infection.