Antiviral treatment of Tick-borne encephalitis TBE - setup of a national multi centre clinical trial

The aim of this application is to design and set-up a Swedish multicentre clinical trial to investigate the efficacy of an anti-viral treatment for patients with Tick-borne Encephalitis (TBE).

The annual incidence of TBE is showing an increasing trend and in some parts of southern Sweden is the highest in Europe. Increasing age is associated with severe disease and mortality due to TBE. Independent of age the Case Fatality Rate is 1-2%, thus higher in elderly individuals. The proportion of patients with long-standing neurological sequel after acute infection is 30-40%.

Also there is an unexplained higher incidence of TBE in men compared to women. Unfortunately, there is no available anti-viral treatment for TBE.

Therefore, we intend to use allocated funds in 2025 to plan for a randomised placebo-controlled blinded clinical trial, starting 2026, to investigate the efficacy of an oral anti-viral drug.

We plan to use the existing infectious diseases network for clinical studies, Action Sweden, to include all high-endemic regions i Sweden.

During 2025 we need allocated time to set up study sites, decide upon the final statistics, study design including the primary clinical endpoint and secondary endpoint including cerebrospinal fluid bio-markers for severity of disease and its relation to improvement and treatment with antivirals. We are also to write regulatory applications and agreement with the pharmaceutical company for manufacturing placebo.