Safety and Immunogenicity Study of GX-19N, a COVID-19 Preventive DNA Vaccine in Healthy Adults

A Phase 1/2a, Multicenter, Randomized, Double-blind, Placebo-controlled Study to Investigate the Safety, Tolerability, and Immunogenicity of GX-19N, a COVID-19 Preventive DNA Vaccine in Healthy Subjects

The objective of our study is to evaluate safety, tolerability, and immunogenicity of COVID-19 preventive DNA vaccine in healthy volunteers.

Study Overview

• Status: Completed
• Conditions: SARS-CoV-2
• Intervention / Treatment: Drug: Placebo; Drug: GX-19N

Detailed Description

This clinical study is phase 1/2a clinical trial to evaluate safety, tolerability, and immunogenicity of COVID-19 preventive vaccine by intramuscularly administration in healthy volunteers.

Phase 1 of this study is designed as single arm, open-labeled and a total of 20 subjects will be enrolled. Phase 2a of study is designed as randomized, double-blind, placebo controlled and a total of 150 subjects are planned to be enrolled.

• Study Type: Interventional
• Enrollment (Actual): 185
• Phase: Phase 2; Phase 1

Contacts and Locations

Study Locations

• Korea, Republic of
  • Seoul, Korea, Republic of, 03722
    • Severance Hospital
  • Seoul, Korea, Republic of, 06273
    • Gangnam Severance Hospital
  • Seoul, Korea, Republic of, 02447
    • Kyunghee University Medical Center
  • Seoul, Korea, Republic of, 04763
    • Hanyang University Hospital
  • Suwon, Korea, Republic of, 16499
    • Ajou University Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 55 years (Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Able and willing to comply with all study procedures and voluntarily signs informed consent form
• Healthy adult male or female aged 19-55 years
• Willing to provide specimens such as blood and urine during the study, including end of study visit.

Exclusion Criteria:

• Immunosuppresion including immunodeficiency disease or family history
• Any history of malignant disease within the past 5 years
• Scheduled to undergo any surgery or dental treatment during the study
• Having received immunoglobulin or blood-derived drugs or being expected to be administered within 3 months prior to administration.
• Having relied on antipsychotic drugs and narcotic analgesics within 6 months before administration
• Positive of serology test at screening
• Suspected of drug abuse or a history within 12 months prior to administration
• Active alcohol use or history of alcohol abuse
• Serious adverse reaction to a drug containing GX-19N or other ingredients of the same categories or to a vaccine or antibiotic, nonsteroidal anti-inflammatory disease control, etc. or an allergic history
• History of hypersensitivity to vaccination such as Guillain-Barre syndrome
• Those who have or with a history of disease corresponding to other hepatobiliary, kidneys, nervous systems (middle or peripheral), respiratory machines (e.g. asthma, pneumonia, etc., endocrine systems (uncontrolled diabetes, hyperlipidemia, etc.) and cardiovascular (congestive heart failure, coronary artery disease, myocardial infarction, uncontrolled hypertension), blood tumors, urinary machines, mental, musculoskeletal systems, immune system (rheumatoid arthritis, systemic arthritis, mumps, immunodeficiency disease)
• Having hemophilia at risk of causing serious bleeding when injected intramuscularly or receiving anticoagulants
• Subjects who have been contact with COVID-19 infections in the past prior to administration, have been classified as COVID-19 confirmed patients, medical patients or patients with symptoms or have been identified with SARS and MERS infection history in the past
• Acute fever, cough, difficulty breathing, chills, muscle aches, headache, sore throat, loss of smell, or loss of taste within 72 hours prior to administration
• Other vaccination history within 28 days prior to the administration or being scheduled to be inoculated during the study
• History of having taken immunosuppressant or Immune modifying drug within 3 months prior to administration
• Having participated and had clinical trial drug administration in another clinical trial or biological equivalence study within 6 months prior to the administration
• Pregnant or breastfeeding female, however, those are allowed to participate in the study only if they stop breastfeeding before participation (fertile female† must be negative in serum pregnancy test at screening
• Fertile female who do not agree to use effective contraception methods (condoms, contraceptive diaphragm, intrauterine contraceptive devices) during the study
• Any other clinically significant medical or psychiatric finding which is considered inappropriate by investigator

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Sequential Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: GX-19: Dose A; Dose A of GX-19N will be intramusculary administered via EP on day 1 and day 29.	Drug: GX-19N; DNA vaccine expressing SARS-CoV-2 S-protein antigen including the Nucleocapsid protein (NP) antigen; Other Names: Dose A
Placebo Comparator: Placebo: Normal saline; Placebo will be intramusculary administered via EP on day 1 and day 29.	Drug: Placebo; Normal saline; Other Names: Normal saline

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of Solicited Adverse Events	solicited local and systemic AEs after vaccination	Through 1 year post vaccination
Incidence of Unsolicited Adverse Events	unsolicited AEs after vaccination	Through 1 year post vaccination
Incidence of Serious Adverse Events	percentage of subjects with SAEs	Through 1 year post vaccination

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
GMT of Antigen-specific Binding Antibody Titers	Geometric mean titer (GMT) of antigen-specific binding antibody after vaccination	Through 1 year post vaccination
GMFR of Antigen-specific Binding Antibody Titers	Geometric mean fold rise (GMFR) of antigen-specific binding antibody after vaccination	Through 1 year post vaccination
Percentage of Subjects Who Seroconverted After Vaccination	Seroconversion defines when FRNT50 is detected more than four times from the baseline after vaccination	Through 1 year post vaccination
GMT and GMFR of Neutralizing Antibody Level	Geometric mean titer (GMT) and Geometric mean fold rise (GMFR) of neutralizing antibody after vaccination	Through 1 year post vaccination
GMFR of Neutralizing Antibody Level	Geometric mean fold rise (GMFR) of neutralizing antibody after vaccination	Through 1 year post vaccination
GMSN and GMFR of Spot Forming Unit (SFU) detected by IFN-gamma ELISPOT assay	Geometric mean spot numbers (GMSN) and Geometric mean fold rise (GMFR) of SFU after vaccination	Through 1 year post vaccination

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change From Baseline in Antigen-specific IFN-gamma Cellular Immune Response	Antigen-specific IFN-γ T cell immune response assessed after vaccination	Through 1 year post vaccination

Collaborators and Investigators

• Sponsor: Genexine, Inc.
• Investigators: Principal Investigator: Jun Yong Choi, MD, Severance Hospital; Study Director: JungWon Woo, Ph.D., Genexine, Inc.

Publications and helpful links

General Publications

• Ahn JY, Lee J, Suh YS, Song YG, Choi YJ, Lee KH, Seo SH, Song M, Oh JW, Kim M, Seo HY, Kwak JE, Youn JW, Woo JW, Shin EC, Sung YC, Park SH, Choi JY. Safety and immunogenicity of two recombinant DNA COVID-19 vaccines containing the coding regions of the spike or spike and nucleocapsid proteins: an interim analysis of two open-label, non-randomised, phase 1 trials in healthy adults. Lancet Microbe. 2022 Mar;3(3):e173-e183. doi: 10.1016/S2666-5247(21)00358-X. Epub 2022 Feb 8.

Study record dates

Study Major Dates

• Study Start (Actual): December 30, 2020
• Primary Completion (Actual): April 19, 2022
• Study Completion (Actual): April 19, 2022

Study Registration Dates

• First Submitted: January 18, 2021
• First Submitted That Met QC Criteria: January 18, 2021
• First Posted (Actual): January 20, 2021

Study Record Updates

• Last Update Posted (Actual): August 20, 2025
• Last Update Submitted That Met QC Criteria: August 18, 2025
• Last Verified: November 1, 2022

More Information

Terms related to this study

• Other Study ID Numbers: GX-19N-HV-002

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No