Ongoing Clinical Trials Investigating Retrovirus-MS Theory

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Two European clinical trials are both investigating a theory that multiple sclerosis may be triggered by activation of human endogenous retroviruses.

Two clinical trials now under way in Europe and the United Kingdom (UK) are investigating a theory that multiple sclerosis (MS) may be triggered by activation of human endogenous retroviruses (HERVs)—remnants of retroviruses that over time became part of the human genome.

The role of HERVs in MS has not been proven, but scientists note that the first full sequences of the human genome show an estimated 8% of the entire genome is made up of sequences encoding retroviral elements that have been shown to become activated under some circumstances. Also contributing to interest in the HERVs theory of MS are several reports that HIV-positive patients have a greatly reduced risk of developing MS, and some studies have suggested that anti-HIV therapy may suppress MS.

One group of UK researchers, sponsored by Queen Mary University and collaborating with Merck Sharp & Dohme Corp., is conducting a trial of raltegravir (Isentress), an HIV drug, in a small number of patients to see if the medication can affect brain lesions seen in MRI scans. The results of this trial may be ready before the end of 2014.

A second trial is under way in Sweden by the company GeNeuro Innovation testing a monoclonal antibody known as GNbAC1 that targets an element of HERVs. Results of the safety trial of GNbAC1 may be reported at the American Academy of Neurology’s annual meeting in April 2014.

According to the online abstract for the meeting’s presentation, in the study the researchers 5 patients were randomized to receive either a single intravenous infusion of 2 mg/kg of GNbAC1 or placebo. Another 5 patients were randomized to receive either an infusion of 6 mg/kg of the antibody or placebo.

“The 12-month results confirm the favorable long-term GNbAC1 safety profile in MS patients and the pharmacokinetics allows monthly administration scheme,” the researchers wrote in conclusion.

They do recommend a larger Phase II study to test the efficacy and safety of using the antibody to targeting the protein.