Actively Recruiting
Safety, Reactogenicity, and Immunogenicity of the HDT-321 RNA Vaccine Against Crimean-Congo Hemorrhagic Fever in Healthy Adults An Open Label, Dose-Escalation Phase 1 Study
Led by HDT Bio · Updated on 2025-07-28
48
Participants Needed
1
Research Sites
30 weeks
Total Duration
On this page
Sponsors
H
HDT Bio
Lead Sponsor
D
DFNet Research Inc.
Collaborating Sponsor
AI-Summary
What this Trial Is About
Researchers are evaluating the safety, tolerability, and immune response of an investigational vaccine called HDT-321 for protection against Crimean-Congo hemorrhagic fever virus (CCHFV) in healthy adults aged 18 to 64 years. This first-in-human, open-label study involves testing three different dosage levels and comparing single or two-dose regimens to better understand the vaccine's effects and safety profile. The study includes four groups of 12 participants each, receiving varying doses of HDT-321: 10 micrograms with two doses, 25 micrograms with two doses, 50 micrograms with one dose, and 50 micrograms with two doses. Participants receive the vaccine by intramuscular injection on day 1, with some groups receiving a second dose on day 29. The study progresses carefully with initial safety monitoring of smaller sentinel groups before enrolling the full group at each dose level. Participants will attend multiple clinic visits and phone calls for safety checks and blood sample collection, including memory aid completion for 7 days after each injection to track side effects. Researchers will monitor adverse events locally and systemically for up to 28 days after each dose, serious events throughout the study lasting up to about 13 months, and will evaluate immune responses until day 57. The study aims to collect detailed safety and immune response data to better understand HDT-321.
CONDITIONS
Brief Title
Safety and Immunogenicity of a Self-Amplifying RNA Vaccine Against Crimean-Congo Hemorrhagic Fever
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Males and non-pregnant females aged 18 to 64 years
- Body mass index (BMI) between 17 and 35 inclusive at screening
- Considered in good general health by medical evaluation within 30 days prior to first study injection
- Screening lab values within normal ranges or with only mild non-clinically significant findings
- Negative tests for HIV 1/2 antibodies, hepatitis B surface antigen, and hepatitis C antibodies
- Women of childbearing potential agree to use contraception or abstinence starting 30 days before first injection through 60 days after last injection, with negative pregnancy tests at screening and before each injection
- Able to understand and comply with study procedures and available for all visits and calls
- Provide written informed consent before any study procedures
- Willing to abstain from donating blood or blood products 30 days before screening and during the study
- Willing to avoid receiving any licensed vaccine within 28 days before and after study injections
You will not qualify if you...
- Any medical condition judged by investigator to pose unacceptable risk or interfere with study participation, including uncontrolled respiratory, cardiovascular, neurological diseases, ongoing or recent cancer (except some skin cancers), blood or liver disorders, autoimmune diseases, or immunodeficiency
- Abnormal screening ECG
- History of severe allergic reactions to vaccines or polyethylene glycol (PEG)-containing products
- Allergy to antibiotics similar to kanamycin
- Use of immunosuppressive drugs for more than 14 days within 6 months before study
- Receipt of immunoglobulins, blood products, or investigational drugs within specified recent periods
- Participation in another clinical trial with investigational agents during study
- Receipt or plan to receive any non-study vaccine within 28 days before or after injections
- Febrile illness within 24 hours before each injection
- Heavy smoking or vaping as defined in the protocol
- Known or suspected alcohol or drug abuse in past 12 months
- Breastfeeding or planning to breastfeed during study period
- Unlikely to comply with study protocol requirements
AI-Screening
AI-Powered Screening
Complete this quick 3-step screening to check your eligibility
Your Study Journey
Duration - 2 to 4 weeks
Participants are screened for eligibility to participate in the trial.
1 visit (in-person)
Duration - Approximately 2 months
Participants receive one or two doses of the HDT-321 investigational vaccine depending on their assigned group. Participants in Groups 1, 2, and 4 receive two doses on Day 1 and Day 29, while participants in Group 3 receive one dose on Day 1. Safety and immune response are closely monitored during this period.
Groups 1, 2, and 4: 10 in-clinic visits including 2 injections and 2 phone calls; Group 3: 9 in-clinic visits including 1 injection and 1 phone call
Duration - Up to approximately 13 months
Participants are monitored for adverse events, serious adverse events, and immunogenicity up to the end of study participation. Blood samples and safety assessments continue during this period to evaluate the long-term safety and immune response to the vaccine.
Additional visits and contacts as needed during the follow-up period
Trial Site Locations
Total: 1 location
1
Flourish Research San Antonio (Clinical Trials of Texas)
San Antonio, Texas, United States, 78229
Actively Recruiting
Research Team
J
James Keary
A
Aude Frevol
How is the study designed?
Study Type
INTERVENTIONAL
Masking
NONE
Allocation
NON_RANDOMIZED
Model
PARALLEL
Primary Purpose
PREVENTION
Number of Arms
4
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