Phase 3 Trial Shows High Cure Rates for Hepatitis C Drug

Glecaprevir is a NS3/4A protease inhibitor and pibrentasvir is a NS5A inhibitor for hepatitis C patients without cirrhosis.

Top-line results for an investigational drug regimen proved a 99% success rate for the hepatitis C virus (HCV).

Glecaprevir/pibrentasvir is indicated as an 8-week treatment for HCV among patients without cirrhosis. It’s a once daily co-formulation dosed in 3 tablets, which the pharmaceutical company, AbbVie, has tested in several clinical trials. Glecaprevir is a NS3/4A protease inhibitor and pibrentasvir is a NS5A inhibitor.

AbbVie is seeking review of the regimen in a New Drug Application (NDA) it filed in December with the FDA. If granted approval, the drug would offer an 8-week ribavirin-free treatment option for patients with HCV across the 6 major genotypes of the virus.

Results on the trial, dubbed the Certain-1 study, involved Japanese patients who were chronically infected with genotype 1 HCV and did not have cirrhosis. It is estimated that more than a million people are infected with HCV in Japan, which has one of the highest infection rates of the virus in the industrialized world.

The phase 3 clinical trial showed that 105 of 106 patients (99%) had sustained virologic response (SVR) 12 weeks after treatment with glecaprevir/pibrentasvir ended; 1 patient was lost to follow up, according to a company news release. Treatment is considered successful when a patient achieves SVR, an indication that the virus is no longer detectable in the blood.

"Due to patient characteristics and virological considerations, people living with hepatitis C in Japan have specific treatment challenges and needs," Michael Severino, MD, executive vice president, research and development and chief scientific officer of AbbVie, stated in the release.

Among those treated with glecaprevir/pibrentasvir who achieved SVR after 8 weeks of treatment, 23 patients had the Y93H variant of the virus, which is associated with reduced cure rates. Japan treatment guidelines recommend that before receiving treatment, some patients involved in a clinical trial get tested for Y93H, an altered amino acid that makes some patients with HCV resistant to first generation NS5A inhibitor-based therapies, a company spokesperson explained.

“The study demonstrated the potential of G/P in patients with specific treatment challenges, including those with the Y93H resistance-associated variant,” AbbVie senior manager of public affairs, Markeisha Marshall, told MD Magazine.

The safety and efficacy of 8 weeks of glecaprevir/pibrentasvir regimen with 12 weeks of ombitasvir/paritaprevir/ritonavir, an approved AbbVie HCV drug, which is marketed in Japan under the brand name Viekirax. The company said it met the study’s primary endpoint, which was to show that the investigational drug was not inferior to that of the 12-week comparator regimen.

Among patients with genotype 1 of the virus who did not have cirrhosis and were treated with glecaprevir/pibrentasvir, no one discontinued treatment as a result of adverse events (AEs). The most common AEs were inflammation of the throat and nasal passages and itchiness.

The news release was provided by AbbVie.