Treatment With ABT-493/ABT-530 Cures 99% of Patients With Hepatitis C Genotype 2

Almost everyone taking immediate ABT-493/ABT-530 (glecaprevir/pibrentasvir, G/P) in an international placebo-controlled trial had a sustained virologic response 12 weeks after treatment ended (SVR12). No one stopped treatment because of adverse events, and no G/P-related serious adverse events developed.

Hepatitis C (HCV) genotype 2 infects about 180 million people across the world. Current U.S. and European Union guidelines recommend sofosbuvir/velpatasvir (Epclusa) for type 2 infection, with sofosbuvir (Sovaldi) plus daclatasvir (Daklinza) as an alternative. Sofosbuvir/velpatasvir yielded an SVR of 99% in an intention-to-treat analysis, and sofosbuvir + daclatasvir yielded an SVR of 93% in an intention-to-treat analysis. ENDURANCE-2 tested a new HCV type 2 candidate, three-pill once-daily G/P, in treatment-naive or experienced patients without cirrhosis. Glecaprevir is an NS3/4A protease inhibitor, and pibrentasvir is an NS5A inhibitor.

This phase 3, double-blind, placebo-controlled trial randomized 202 genotype 2 participants to immediate G/P for 12 weeks and 100 participants to placebo for 12 weeks followed by G/P for 12 weeks. Participants lived in the United States, Europe, Korea or Taiwan. All participants were at least 18 years old; none had experience with a direct-acting antiviral (DAA) other than sofosbuvir; none had hepatitis B or HIV infection; and none had cirrhosis, a solid organ transplant or hepatocellular carcinoma.

The G/P and placebo groups were similar in proportions of men (49% and 45%), whites (60% and 60%), Asians (34% and 32%), treatment experience (30% and 29%) and proton pump inhibitor use (11% and 11%). The groups were similar in age (median 58 and 59 years) and baseline HCV RNA (6.25 and 6.39 log10 IU/mL). Among 160 participants sequenced for baseline polymorphisms linked to resistance to current DAAs, 83% had NS5A-related polymorphisms only and none had NS3 polymorphisms.

In an intention-to-treat population excluding six sofosbuvir-treated patients, 195 of 196 participants (99%) achieved SVR12. (The six excluded patients also achieved SVR12.) In a modified intention-to-treat population excluding one patient with nonvirologic failure who achieved SVR4, all 195 participants achieved SVR12. There were no virologic failures. Neither treatment experience nor any other factor affected achievement of SVR12. Statistical analysis indicated that G/P is superior to the 95% SVR12 rate with sofosbuvir plus ribavirin (Rebetol).

Overall adverse event rates were 65% in the immediate G/P arm and 58% in the placebo arm. Three participants in the immediate arm (1%) and one in the placebo arm (1%) had a serious adverse event, but none of these were related to treatment and no one in either arm had an adverse event leading to study drug discontinuation. The most frequent adverse events in the immediate G/P arm were headache in 12% and fatigue in 11%. Grade 3 or 4 aspartate aminotransferase elevations affected two (1%) in the immediate G/P arm; one person (0.5%) in that arm had a grade 3 or greater alanine aminotransferase elevation, and one had a grade 3 or greater total bilirubin elevation.

Mark Mascolini writes about HIV and hepatitis virus infection.