Curing hepatitis C virus (HCV) may dial back some forms of cognitive decline in those with and without HIV.

Publishing the findings of their ongoing study in a letter in the journal Neurology, German researchers designed an open observational trial of individuals with HCV who did and did not have HIV. They also assessed a group of controls (individuals who did not have either virus) to serve as a comparison to the others before they started hep C treatment.

None of the participants who had HCV had cirrhosis of the liver, a history of substance dependence or cerebral diseases. All those with HIV had an undetectable viral load for at least six months.

The participants received a battery of tests of cognitive function, some of which were based on self-reporting. These tests were taken upon entry into the study and a second time at least 12 weeks after completing treatment for HCV.

In 2015 and 2016, the researchers assessed 25 HCV-positive individuals, 15 of whom had HIV. All but one individual was male.

At the study’s outset, those with hep C had significantly poorer performance with regard to visual and working memory, processing speed, attention and executive function (which includes a series of cognitive processes integral for cognitive control over behavior) compared with the control group. The researchers did not see a difference in cognitive function based on HIV status.

So far, 12 of the participants have completed HCV treatment: two with Technivie (ombitasvir/paritaprevir/ritonavir) plus ribavirin, nine with Harvoni (ledipasvir/sofosbuvir) and one with Sovaldi (sofosbuvir) plus ribavirin. All of them achieved a sustained virologic response 12 weeks after completing therapy (SVR12, considered a cure).

Tests indicated that between the study’s outset and the follow-up assessment, those who were cured of hep C experienced improvements in visual memory, processing speed, attention and executive functioning. The severity of fatigue also declined while self-reported quality of life improved.

The study is limited by its small sample size.

To read the Neurology letter, click here.