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VLA1601

Phase 1

Zika | Monoclonal antibody | Infectious Disease |Valneva SE|Last Updated: Mar 9, 2026

Success Probability

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Trial Design

RandomizedDouble-BlindCONTROLLEDDMC
Total Trials1
Total Enrollment150

FDA Designations

No designations recorded

Clinical trial landscape

VLA1601 · 2 trials · 3 indications

Phase 1 2
NCT06334393Phase 1 Trial to Assess the Safety and Immunogenicity of an Inactivated, Adjuvanted Whole Zika Virus Vaccine Candidate (VLA1601) in Healthy AdultsZika
COMPLETED150 Analytics
NCT03425149Randomized, Placebo-controlled, Observer-blinded Phase 1 Safety and Immunogenicity Study of Inactivated Zika Virus Vaccine Candidate in Healthy AdultsZika Virus
COMPLETED67 Analytics
PHASE1COMPLETED
Phase 1 Trial to Assess the Safety and Immunogenicity of an Inactivated, Adjuvanted Whole Zika Virus Vaccine Candidate (VLA1601) in Healthy Adults
ZikaUnlock trial analytics
PHASE1COMPLETED
Randomized, Placebo-controlled, Observer-blinded Phase 1 Safety and Immunogenicity Study of Inactivated Zika Virus Vaccine Candidate in Healthy Adults
Zika VirusUnlock trial analytics

Study Endpoints

Primary Endpoints

Solicited Adverse Events
7 days after each vaccination

frequency of solicited AEs (injection site and systemic reactions)

Neutralizing antibodies against ZIKA virus (ZIKV)
Day 57

Geometric mean titer (GMT) for neutralizing antibodies against (ZIKV) determined by virus neutralization assay

Rate of subjects with solicited adverse events including injection site and systemic reactions
within 7 days after any vaccination

Secondary Endpoints

Solicited Adverse Events
7 days after any vaccination
Unsolicited AEs
Day 395
Vaccine-related unsolicited AEs
Day 395
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Study Design & Arms

AllocationRANDOMIZED
MaskingTRIPLE
ModelPARALLEL
PurposePREVENTION

Treatment Arms

ArmTypeDescription
VLA1601 Low doseEXPERIMENTAL -
VLA1601 Low dose + CpG 1018®EXPERIMENTAL -
VLA1601 Low dose + 3M-052-AFEXPERIMENTAL -
VLA1601 Medium doseEXPERIMENTAL -
VLA1601 High doseEXPERIMENTAL -
Treatment Group IEXPERIMENTAL0.5 ml (6 antigen units (AU)) of VLA1601 on Day 0 and 28, 0.5 ml Placebo on Day 7
Treatment Group IIEXPERIMENTAL0.5 ml (6 antigen units (AU)) of VLA1601 on Day 0 and 7, 0.5 ml Placebo on Day 28
Treatment Group IIIEXPERIMENTAL0.25 ml (3 antigen units (AU)) of VLA1601 on Day 0 and 28, 0.25 ml Placebo on Day 7
Treatment Group IVEXPERIMENTAL0.25 ml (3 antigen units (AU)) of VLA1601 on Day 0 and 7, 0.25 ml Placebo on Day 28
Treatment Group VPLACEBO_COMPARATOR0.5 ml Placebo on Day 0, 7 and 28

Interventions

NameTypeDescription
VLA1601BIOLOGICAL0.45mL (milliliter), Day 1 and 29
CpG 1018®BIOLOGICALCpG 1018® will be investigated in combination with VLA1601 Low dose
3M-052-AFBIOLOGICAL3M-052-AF will be investigated in combination with VLA1601 Low dose
PlaceboBIOLOGICALPhosphate buffered saline (PBS)
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Eligibility Criteria

Age Range18 Years to 49 Years
SexALL
Healthy VolunteersYes
Study Sites4

Key Inclusion Criteria: * 18 to 49 years of age * BMI of ≥18.5 and \<30 kg/m2 * generally healthy as determined by the investigator's clinical judgement based on medical history, physical examination, and screening laboratory tests. * If trial participant is of childbearing potential: negative preg...

Countries:United States
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Frequently asked questions about VLA1601

What is VLA1601 used for?

VLA1601 is an investigational vaccine candidate being developed for the prevention of Zika virus infection. It is designed to generate an immune response against the Zika virus in healthy adults. The vaccine is currently in clinical development and has not been approved by regulatory authorities.

Who makes VLA1601?

VLA1601 is being developed by Valneva SE, a biopharmaceutical company. Valneva is publicly traded on the stock exchange under the ticker symbol VALN. The company is conducting clinical trials to evaluate the safety and immunogenicity of this vaccine candidate.

What phase is VLA1601 in?

VLA1601 is in Phase 1 clinical development. Two Phase 1 trials have been completed, both of which were randomized, placebo-controlled, and observer-blinded studies. The vaccine remains investigational and has not received regulatory approval for use outside of clinical trials.

What clinical trials is VLA1601 in?

VLA1601 has been studied in two completed Phase 1 clinical trials. The first trial, NCT03425149, enrolled 67 healthy adults in the United States. The second trial, NCT06334393, enrolled 150 healthy adults. Both trials assessed the safety and immunogenicity of the vaccine candidate.

How does VLA1601 work?

VLA1601 is an inactivated whole Zika virus vaccine. It contains a whole Zika virus that has been inactivated, meaning it cannot cause disease. When administered, it is designed to stimulate the immune system to produce antibodies against the Zika virus, potentially providing protection against infection.

Is VLA1601 the same as an inactivated Zika vaccine?

Yes, VLA1601 is an inactivated, adjuvanted whole Zika virus vaccine candidate. The vaccine contains an inactivated form of the Zika virus, which is combined with an adjuvant to enhance the immune response. It is being evaluated for its ability to prevent Zika virus infection.