Phase 3 Trial Reveals High Hepatitis C Success Rate with Investigational Drug

Glecaprevir/pibrentasvir had a 99% SVR rate in a Japanese population.

Top-line results for an investigational drug regimen proved a 99% success rate for hepatitis C.

Glecaprevir/pibrentasvir is indicated as an eight-week treatment for hepatitis C among patients without cirrhosis. It’s a once daily co-formulation dosed in three 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 US Food and Drug Administration (FDA). If granted approval, the drug would offer an eight-week ribavirin-free treatment option for patients with hepatitis C across the six major genotypes of the virus.

Results on the trial, dubbed the Certain-1 study, involved Japanese patients who were chronically infected with genotype 1 hepatitis C and did not have cirrhosis. It is estimated that more than a million people are infected with hepatitis C 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 out of 106 patients (99%) had sustained virologic response (SVR) 12 weeks after treatment with glecaprevir/pibrentasvir ended; one 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 eight 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 hepatitis C 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 eight weeks of glecaprevir/pibrentasvir regimen with 12 weeks of ombitasvir/paritaprevir/ritonavir, an approved AbbVie hepatitis C 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. The most common side effects were inflammation of the throat and nasal passages and itchiness.

The news release was provided by AbbVie.

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