New Hepatitis C Treatments

As if there weren’t enough treatments for Hepatitis C already, results of another Hepatitis C treatment trial were presented on Monday at IAS 2017.

Karine Lacombe of Saint-Antoine Hospital in Paris presented findings from AbbVie's phase 3 EXPEDITION-2 trial, which evaluated an 8-week regimen of glecaprevir/pibrentasvir for people with both HIV and hepatitis C.

Glecaprevir is an HCV NS3/4A protease inhibitor and pibrentasvir is an NS5A inhibitor. Both are pangenotypic, or active against all HCV genotypes. The two drugs have been co-formulated in a once-daily combination pill, to be marketed under the brand name Maviret.

Studies in the DAA era have shown that HIV-positive people generally do as well on interferon-free regimens as those without HIV – though it is important to take into account the potential for drug interactions between DAAs and antiretrovirals – and they are no longer considered a "special population." Yet European and US HCV treatment guidelines currently do not recommend shorter treatment for people with HIV and HCV co-infection.  A shorter course of treatment could potentially improve adherence and reduce cost.

EXPEDITION-2 enrolled 153 HIV-positive people with chronic hepatitis C in Europe, the United States and Russia. More than 80% were men and the median age was approximately 45 years. About two-thirds had HCV genotype 1 (mostly with harder-to-treat subtype 1a), followed by genotypes 3 (17%) and 4 (11%); a small number had genotypes 2 or 6.  People with Hep B co-inbfection were excluded.

Sixteen participants (10%) had liver cirrhosis, and most of the rest had absent or mild fibrosis. Nearly 20% were previously treated with interferon and ribavirin, and three had also used sofosbuvir (Sovaldi).  Study participants had well-controlled HIV infection with a median CD4 count of nearly 600 cells/mm³.  All but nine were on antiretroviral therapy, and about three-quarters of treated people were taking the integrase inhibitors raltegravir (Isentress) or dolutegravir (Tivicay), which were shown to have minimal interactions with glecaprevir and pibrentasvir.  They had variable backbones including TDF, FTC, TAF, lamivudine.  I’ve included the drug-drug interaction profiles out of interested, as presented at the session.

Participants without cirrhosis received glecaprevir/pibrentasvir for 8 weeks, while those with cirrhosis were treated for 12 weeks. Everyone received the study drugs and there was no placebo arm.

 Treatment was highly effective, with 98% having continued undetectable HCV RNA at 12 weeks post-treatment (SVR12). The cure rate rose to 99%, with no virological failures, for people without cirrhosis who were treated for 8 weeks.

A single patient with HCV genotype 3 and cirrhosis, who reported less than complete (85%) adherence, experienced virological failure during treatment. Another participant had missing data at 12 weeks post-treatment, but returned for care at 24 weeks post-treatment and was found to be cured.

 Glecaprevir/pibrentasvir was generally safe and well tolerated. Adverse events were similar to those seen in studies of HIV-negative people. One participant with cirrhosis stopped treatment early due to an adverse event that was not considered drug-related (stroke and brain haemorrhage). The most common adverse events were fatigue, nausea, headache, and nose and throat inflammation.

 "These results suggest that the glecaprevir/pibrentasvir regimen could be the first 8-week, pangenotypic treatment option for HCV/HIV-1 coinfected patients without cirrhosis," the researchers concluded.

This could be a bonus for co-infected patients but caution with drug-drug interactions is still an issue.  However, given the short duration of therapy these may or may not be significant.