Merck's Investigational Hepatitis C Treatment Confirms Proof-of-Concept

A study exploring Merck’s experimental hepatitis C virus (HCV) treatment has provided proof-of-concept for a 6- to 8-week course of the triple therapy in treatment-naïve patients, including those with cirrhosis.

The C-SWIFT study examined Merck’s HCV treatment regimen comprised of grazoprevir/elbasvir, the company’s NS3/4A protease inhibitor, in combination with sofosbuvir, a nucleotide NS5B inhibitor.

According to Merck, 4 weeks of the triple therapy course resulted in “sub-optimal efficacy,” as only 38.7% of the 102 cirrhotic and non-cirrhotic patients in the study showed sustained virologic response (SVR) after 4 weeks of treatment. However, in double that time, 94.7% of the patients showed an SVR.

The 28 patients who did not achieve SVR at 4 to 8 weeks following treatment relapsed after the end of therapy. Some of these patients had wild type virus, others had elbasvir-resistant viral variants, and 1 patient had variants resistant to both grazoprevir and elbasvir.

The most common complaints related to the regimen were headache (4%), fatigue (2%) and nausea (2%). According to Merck’s press release, the administration of grazoprevir/elbasvir and sofocbuvir was “generally well-tolerated.”

“These interim data provide a compelling proof-of-concept for the potential of an 8- or 6-week triple therapy course in treatment-naive patients with genotype 1 disease, including cirrhotic patients,” said Eric Lawitz, MD, vice president of scientific and research development at the Texas Liver Institute and C-SWIFT lead investigator. “These findings will inform the design of larger studies aimed at understanding the potential of short-duration triple therapy across multiple patient types.”