Relapse common in HIV/HCV co-infected patients after treatment for HCV

Relapse after apparently successful treatment for hepatitis C virus occurs in over a third of individuals who are co-infected with HIV and hepatitis C, Spanish investigators report in the November 1^st edition of Clinical Infectious Diseases.

Relapses were more common in co-infected patients who carried the harder-to-treat hepatitis C 1 and 4 genotypes. Most relapses occurred within three months of the completion of hepatitis therapy, and re-infection with hepatitis C accounted for most of the apparent relapses seen after this time.

A significant proportion of HIV-positive individuals are co-infected with hepatitis C virus, and liver disease caused by this co-infection is now an important cause of illness and death in patients with HIV.

Treatment is available for hepatitis C and consists of pegylated interferon and ribavirin dosed by weight. The length of treatment depends on which hepatitis C genotype an individual is infected with: the harder-to-treat genotypes 1 and 4 require 48 weeks of therapy, whereas genotypes 2 and 3 are treated for 24 weeks.

The goal of hepatitis C treatment is an undetectable hepatitis C viral load 24 weeks after the completion of treatment. Only about a third of HIV-positive patients with chronic hepatitis C achieve this outcome, which is a significantly poorer treatment response rate to that seen in hepatitis C mono-infected individuals (approximately 50%).

It is generally assumed that once a patient had achieved a sustained response to hepatitis C therapy that they have been cured of their infection and that the chance of relapse is very low.

Investigators in Madrid wished to get a better understanding of the prevalence and timing of relapse to hepatitis C therapy. They hope that their findings will help inform the optimum time to use new hepatitis C drugs that are currently in development.

The investigators therefore undertook a retrospective study involving 604 patients who received hepatitis C treatment between 2001 and 2007. Approximately two-thirds of the study sample (64%) were HIV-positive.

A total of 275 (46%) patients had an undetectable hepatitis C viral load after completing therapy for the infection. But only 37% of co-infected patients achieved this outcome compared to 61% of those who were only infected with hepatitis C.

Moreover, co-infected patients were more likely to experience a relapse than mono-infected individuals (33% vs 22%).

Relapses were seen in 41% of co-infected patients who carried genotypes 1 and 4.

All but three of the relapses occurred within three months of treatment for hepatitis C being completed.

Of the three relapses that occurred after this time, two were thought to by the investigators to be cases of re-infection. Phylogenetic analysis revealed that these two patients were infected with a strain of hepatitis C that was distinct from the that for which they were treated.

“Hepatitis C relapse after successful peginterferon plus ribavirin therapy is more common in hepatitis C/HIV-coinfected patients than in hepatitis C-monoinfected patients,” conclude the investigators.

They add, “regardless of HIV infection status, hepatitis C relapse is more common in patients infected with hepatitis C genotypes 1 and 4…and almost always occurs within the first twelve weeks after discontinuation of treatment. Most occurrences beyond twelve weeks are reinfections.”