In short
Tick-borne encephalitis virus (inactivated), neudoerfl strain is the active substance in TICOVAC, a vaccine against tick-borne encephalitis (TBE) authorised in Italy and other European countries. In the clinical trial listed here, the vaccine is not the medicine being tested but an auxiliary medicine used in a Phase 1/2 study of an experimental gene therapy for X-linked immunodeficiency with hyper-IgM type 1 (HIGM1). The trial is authorised and plans to enrol six patients.
Key points
- TICOVAC is an authorised vaccine against tick-borne encephalitis, a viral infection of the brain and spinal cord.
- The vaccine contains inactivated tick-borne encephalitis virus of the neudoerfl strain.
- In the trial listed here, TICOVAC is used as an auxiliary medicine, not as the treatment being studied.
- The trial is a Phase 1/2 study in patients with X-linked hyper-IgM syndrome type 1, with six participants planned.
- The study is currently authorised and investigates an experimental gene-edited cell therapy.
- TICOVAC is given as a suspension for injection into a muscle, in adult and paediatric strengths.
What is tick-borne encephalitis virus?
Tick-borne encephalitis virus (inactivated), neudoerfl strain is the active substance in TICOVAC, a whole-virus inactivated vaccine against tick-borne encephalitis (TBE). TBE is an infection caused by a virus of the Flaviviridae family that affects the brain, the meninges and the spinal cord. The vaccine is authorised as a medicine in Italy, where the marketing authorisation holder is Pfizer S.R.L. The product is available in two strengths: a 0.25 ml paediatric formulation and a 0.5 ml formulation for older children and adults. In the clinical trial record listed on this page, TICOVAC appears as an auxiliary medicine rather than as the substance under investigation.
How does tick-borne encephalitis virus work?
TICOVAC contains whole tick-borne encephalitis virus that has been inactivated so that it cannot cause disease. When injected, the inactivated virus prompts the immune system to produce antibodies against TBE. In clinical studies of TBE vaccines, all subjects analysed for immunogenicity achieved post-immunisation levels of TBE antibodies that met the definition of seroconversion or represented a fourfold increase. TBE vaccines provide protection from the infection caused by the tick-borne encephalitis virus.
Which conditions is it used or studied for?
- Tick-borne encephalitis (TBE) — a viral infection of the brain, meninges and spinal cord transmitted by ticks. TICOVAC is authorised for vaccination against this disease.
- X-linked immunodeficiency with hyper-IgM type 1 (HIGM1) — a rare inherited immune system disease. In the trial listed here, TICOVAC is used as an auxiliary medicine alongside an experimental gene therapy for HIGM1, not as a treatment for the condition itself.
How is tick-borne encephalitis virus given?
TICOVAC is a suspension for injection given by intramuscular injection. The vaccine is supplied in pre-filled syringes in two strengths: a 0.25 ml paediatric formulation and a 0.5 ml formulation. In the trial record, the product names appear in Italian as TICOVAC 0.25 ml per uso pediatrico and TICOVAC 0.5 ml.
What do the clinical trials show?
One trial in the registry involves this substance. The trial is an open-label, single-arm Phase 1/2 study with a planned enrolment of six patients with X-linked hyper-IgM syndrome type 1 (HIGM1). The medicine being investigated is not TICOVAC but an autologous CD4+ T-cell product edited at the CD40LG locus by CRISPR/Cas9, given by intravenous infusion. TICOVAC appears in the trial as an auxiliary medicine, along with other vaccines including a rabies vaccine and a combined diphtheria, tetanus, pertussis, hepatitis B, polio and Haemophilus influenzae type b vaccine.
The primary outcome of the trial is the proportion of patients experiencing dose-limiting toxicities after each dose of the investigational drug product. The study is currently authorised, meaning it has received regulatory approval to proceed but has not necessarily started enrolling participants.
What side effects are known?
Clinical data on TBE vaccines of this type come from a clinical database of approximately 7,500 subjects aged 1 to 77 years across eight clinical trials. The pooled data revealed the expected rate of solicited local and systemic reactions, the majority of which were mild and transient. Pharmacovigilance data from 18 countries where these vaccines have been licensed since 2001 confirmed a high level of safety: only a common range of the side effects already noted for licensed TBE vaccines was reported, and after distribution of more than five million vaccine doses no potential safety risk was noted.