Phase I study to evaluate the safety, tolerability, and pharmacokinetic characteristics of intravenous (IV) administration of a human monoclonal antibody directed against tick-borne encephalitis virus in healthy adults
Summary description of the study
This phase I study aims to evaluate the safety, tolerability, and pharmacokinetic characteristics of TBE025, a human monoclonal antibody developed against the tick-borne encephalitis virus (TBEV). This is the first administration of this product in humans. TBE025 has shown promising preclinical efficacy in mice for the prevention and early treatment of infection. The study is conducted in healthy adults, divided into three groups, each receiving a progressively increasing dose (200 mg, 600 mg, 2000 mg) via intravenous infusion (single dose). The objective is to assess safety, tolerability, and the immune system's response, including the presence and duration of the antibody in the blood. Participants will be followed for 12 weeks through 9 visits, including blood tests, ECG, and monitoring for adverse effects. Although there is no direct benefit to participants, this study aims to address an unmet medical need in the face of a potentially serious viral disease with no specific treatment available to date.
(BASEC)
Intervention under investigation
The intervention studied consists of the administration of an experimental human monoclonal antibody, named TBE025, specifically directed against the tick-borne encephalitis virus (TBEV). This antibody works by binding to a specific region of the virus, thereby preventing it from entering human cells and causing an infection.
The antibody is administered intravenously (IV) as a single dose in a strictly hospital setting, at the Immunotherapy and Vaccinology Center (VIC) of CHUV in Lausanne. The administration is performed via intravenous infusion according to the following three cohorts:
- Cohort 1: 200 mg
- Cohort 2: 600 mg
- Cohort 3: 2000 mg
The first participant in each cohort receives the dose and is observed for one week before the others are included. The study includes a rigorous follow-up of 12 weeks, consisting of 9 medical visits.
(BASEC)
Disease under investigation
Tick-borne encephalitis (TBE): a serious viral disease transmitted by ticks, which can lead to significant neurological complications (meningitis, encephalitis) and even death.
(BASEC)
1. Healthy adults aged 18 to 55 years 2. No history of severe autoimmune disease 3. No participation in another clinical trial or use of an experimental drug in the 30 days prior (BASEC)
Exclusion criteria
1. Pregnancy or breastfeeding; lack of effective contraception if of childbearing age 2. Vaccination with a live vaccine in the 30 days preceding the study (e.g., yellow fever, dengue, etc.) 3. Presence of chronic diseases or unstable health conditions incompatible with a phase I study (BASEC)
Trial sites
Lausanne
(BASEC)
Sponsor
Centre Hospitalier Universitaire Vaudois
(BASEC)
Contact
Contact Person Switzerland
Laura Molinari
0795560626
laura.molinari@clutterchuv.chCHUV Service d'Immunologie et Allergie
(BASEC)
Name of the authorising ethics committee (for multicentre studies, only the lead committee)
Ethics Committee Vaud
(BASEC)
Date of authorisation
23.02.2026
(BASEC)
ICTRP Trial ID
NCT07377253 (ICTRP)
Official title (approved by ethics committee)
A phase I study to investigate the safety, tolerability, and pharmacokinetic characteristics of intravenous (IV) administration of a human monoclonal antibody against tick-borne encephalitis virus in healthy adults (BASEC)
Academic title
A Phase I Study to Investigate the Safety, Tolerability, and Pharmacokinetic Characteristics of Intravenous (IV) Administration of a Human Monoclonal Antibody Against Tick-borne Encephalitis Virus in Healthy Adults. (ICTRP)
Public title
First-in-Human Study Testing a New Antibody Treatment for Tick-Borne Encephalitis in Healthy Volunteers. (ICTRP)
Disease under investigation
The Tick-borne Encephalitis Virus (TBEV) (ICTRP)
Intervention under investigation
Drug: Human monoclonal antibody TBE025, intravenous infusion (ICTRP)
Type of trial
Interventional (ICTRP)
Trial design
Allocation: Non-Randomized. Intervention model: Sequential Assignment. Primary purpose: Treatment. Masking: None (Open Label). (ICTRP)
Inclusion/Exclusion criteria
Inclusion Criteria: - Adults aged 18 to <55 years - Good general health (medical history, physical exam, normal labs) - Written informed consent provided - Ability to read and understand local language - Contraception requirements : Women of childbearing potential: negative pregnancy test, surgically sterile, postmenopausal, or using highly effective contraception for 3 months post-infusion. Men: surgically sterile or using highly effective contraception (self or partner) and abstain from sperm donation for 3 months post-infusion.Exclusion Criteria: - BMI <19 or >30 - Infections: HIV, active hepatitis B (HBsAg), active hepatitis C - Prior participation in investigational study within 30 days - History of hypersensitivity to monoclonal antibodies - Recent surgery or unresolved adverse events - Active autoimmune disease requiring systemic treatment - Recent use of immunosuppressive agents or immunoglobulins - Immunodeficiency diagnosis - Significant cardiovascular events within 6 months - Live/attenuated vaccines within 28 days - Major surgery within 28 days - Pregnancy or breastfeeding - Professional or private link with the research team - Any condition judged by the investigator to interfere with safety or study results (ICTRP)
not available
Primary and secondary end points
Maximum Tolerated Dose (MTD) of TBE025;Incidence and severity of adverse events (AEs);Incidence and severity of Dose Limiting Toxicity (DLT) (ICTRP)
Pharmacokinetic profile of TBE025;Presence of anti-drug antibodies (ICTRP)
Registration date
18.11.2025 (ICTRP)
Incorporation of the first participant
not available
Secondary sponsors
Rockefeller University (ICTRP)
Additional contacts
Laura Molinari, laura.molinari@chuv.ch, +41795560626 (ICTRP)
Secondary trial IDs
SVRI01 (ICTRP)
Results-Individual Participant Data (IPD)
not available
Further information on the trial
https://clinicaltrials.gov/study/NCT07377253 (ICTRP)
Results of the trial
Results summary
not available
Link to the results in the primary register
not available