Norovirus Challenge Study

Completed · Phase 1/Phase 2 · Has a placebo group

Conditions studied: Norovirus Infections

In brief

This is a Phase 2b randomized, double-blind, placebo-controlled vaccination and challenge study to assess the protective efficacy of the Vaxart Norovirus vaccine (VXA-G1.1-NN). Healthy adults will be randomized in a 1:1 ratio to receive one oral dose of vaccine or placebo. * Arm 1: VXA-G1.1-NN oral vaccine tablets \[1x1011 IU±0.5 log\] * Arm 2: Placebo tablets similar in appearance and number to active vaccine tablets Approximately 28 days post-vaccination, subjects will be admitted to an isolation ward and challenged with the NV GI.1 Norwalk challenge strain. After challenge, subjects will be monitored for signs and symptoms of acute gastroenteritis (AGE) from Day 29 to discharge. At 4 days post challenge (Day 33) asymptomatic subjects will be discharged from the isolation ward and will be followed in a series of outpatient visits and telephone calls. Symptomatic subjects may be kept in the isolation ward for up to an additional 3 days.

Key facts

Study ID: NCT05212168
Run by: Vaxart
People needed: 165
Starts: 2021-12-27
Expected to finish: 2023-10-27
Last updated by the study team: 2025-11-05

Who can join

Age: 18 and older, up to 49. Sex: any. Healthy volunteers: accepted.

You may qualify if…

Male or female between the ages of 18 - 49 years, inclusive
Able to give written informed consent
Healthy, as determined by the principal investigator (PI) or PI in consultation with the research monitor and Sponsor Healthy = No clinically significant health concerns or medical illness, as determined by medical history, physical examination, vital signs, electrocardiogram (ECG), and clinical laboratories (complete blood count (CBC), chemistry and urinalysis)
Comprehension of the study requirements with ability and willingness to complete all assessments and comply with confinement period post viral challenge, and all scheduled visits and contacts
Confirmed blood type (A or O)
Demonstrated to be H type-1 antigen secretor positive (by saliva test)
Body mass index between 17 and 35 kg/m2, inclusive, at Screening
Female participants must have a negative pregnancy test at pre-vaccination and pre-challenge and fulfill one of the following Criteria:
At least one year post-menopausal;
Surgically sterile;
Use of oral, implantable, transdermal or injectable contraceptives for 30 days prior to immunization and until 60 days after challenge;
i. A reliable form of contraception must be approved by the Investigator (eg, double barrier method, Depo-Provera, intrauterine device, Norplant, oral contraceptives, contraceptive patches) d. Not be sexually active (abstinent) or in a same sex relationship (must be discussed with site staff and documented)
Male subjects must agree not to father a child or donate sperm, as well as to use contraception/barrier (a male condom) or be abstinent from heterosexual intercourse, from vaccination through the active period (Day 57)

You may not qualify if…

Administration/use of any investigational drug or device 30 days prior to vaccination through the active period (Day 57)
Administration of any licensed vaccine within 30 days prior to vaccination or planned use of the above stated during the active period (through Day 57)
Presence of a significant medical condition, which, in the opinion of the investigator, precludes participation in the study. Significant medical condition = for example, psychiatric conditions, or gastrointestinal disease, such as peptic ulcer, symptoms or evidence of active gastritis or gastroesophageal reflux disease, inflammatory bowel disease, alcohol or illicit drug abuse/dependency, or other laboratory abnormalities
Laboratory values outside the range of normal for platelet counts and the following coagulation tests: prothromibin time test (PT/INR), activated partial thromboplastine time test (aPTT) and fibrinogen
Any of the following history or conditions that may lead to higher risk of clotting events and/or thrombocytopenia:
Family or personal history of bleeding or thrombosis
History of heparin-related thrombotic events, and/or receiving heparin treatments
History of autoimmune or inflammatory disease
Presence of any of the following conditions known to increase risk of thrombosis within 6 months prior to screening:
Recent surgery other than removal/biopsy of cutaneous lesions
Immobility (confined to bed or wheelchair for 3 or more successive days)
Head trauma with loss of consciousness or documented brain injury
Receipt of anticoagulants for prophylaxis of thrombosis
Recent clinically significant infection
Any one of the following ECG findings within 45 days prior to vaccination:
Exclusionary ECG findings:
QTc F (interval duration > 450 msec (male) or > 470 msec (female)
QRS interval greater than 120 msec
PR interval greater than 220 msec
Clinically significant ST-T wave changes or pathologic Q waves
History of cancer or cancer treatment within past 3 years (excluding basal cell or squamous cell carcinomas)
Presence of immunosuppression or medical condition possibly associated with impaired immune responsiveness, including diabetes mellitus or angioedema
Donation or use of blood or blood products within 30 days prior to vaccination through the active period (Day 57)
Diagnosed bleeding disorder or significant bruising or bleeding difficulties that could make blood draws problematic
Any condition that resulted in the absence or removal of the spleen

Where it is running

AltaSciences LA — Cypress, California, United States

Full record on ClinicalTrials.gov

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