HDT-321 Vaccine for Crimean-Congo Hemorrhagic Fever

Overseen By James Keary

Age: 18 - 65

Sex: Any

Trial Phase: Phase 1

Sponsor: HDT Bio

Must not be taking: Immunosuppressants, Immunemodifying drugs

Disqualifiers: Significant respiratory, cardiovascular, neurological, malignancy, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 11

Duration: 8 weeks

48 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores a new vaccine, HDT-321, to determine its safety and effectiveness in preventing Crimean-Congo Hemorrhagic Fever, a severe viral disease. Participants will receive either one or two doses of the vaccine and will undergo monitoring for side effects and immune response through phone calls, clinic visits, and blood tests. The trial seeks healthy adults who have not recently received vaccines and do not have specific health conditions that might complicate participation, such as poorly controlled asthma or significant heart issues. As a Phase 1 trial, participants will be among the first to receive this new vaccine, aiding researchers in understanding its effects in people.

Do I need to stop taking my current medications for the trial?

The trial protocol does not specify if you need to stop taking your current medications. However, if you are on immunosuppressants or immune-modifying drugs, you may need to stop them if taken for more than 14 days in the past 6 months. It's best to discuss your specific medications with the trial team.

Is there any evidence suggesting that HDT-321 is likely to be safe for humans?

Research has shown that HDT-321 has been tested in animals and may help protect against Crimean-Congo Hemorrhagic Fever (CCHF). However, the tolerance in humans remains unknown. This clinical trial is in its early stages, focusing primarily on the vaccine's safety and potential side effects. Early-stage trials are crucial for gathering initial safety information, so researchers closely monitor participants for any unexpected medical issues. While specific data on human safety is not yet available, this trial marks the first step in assessing the safety of HDT-321 for people. ^{1 2 3 4 5}

Why do researchers think this study treatment might be promising for Crimean-Congo hemorrhagic fever?

Researchers are excited about the HDT-321 vaccine for Crimean-Congo Hemorrhagic Fever because it represents a novel approach to preventing this severe viral disease. Unlike traditional treatments that primarily focus on managing symptoms, HDT-321 is designed to stimulate the immune system to prevent infection in the first place. This innovative vaccine targets the virus more directly, potentially offering broader and longer-lasting protection. Additionally, the flexibility of dosing schedules, ranging from single to double doses with varying strengths, allows for the optimization of immune response based on individual needs. This adaptability makes HDT-321 a promising candidate in the fight against Crimean-Congo Hemorrhagic Fever.

What evidence suggests that the HDT-321 vaccine might be an effective treatment for Crimean-Congo hemorrhagic fever?

Research has shown that the HDT-321 vaccine might protect against Crimean-Congo Hemorrhagic Fever (CCHF) based on animal tests. In these studies, the vaccine successfully protected various animals from CCHF. Notably, a similar vaccine using a single dose fully protected mice from the virus. This trial will evaluate different dosing schedules of HDT-321 in humans, with some participants receiving a single dose and others receiving two doses. These findings suggest that HDT-321 could be effective in humans, but human studies are still needed to confirm this. ^{1 2 4 6 7}

Who Is on the Research Team?

Malcolm Duthie, PhD

Principal Investigator

HDT Bio

Are You a Good Fit for This Trial?

This trial is for individuals who are healthy and willing to receive a new vaccine against Crimean-Congo Hemorrhagic Fever. Participants will get one or two doses of the HDT-321 vaccine and must be available for follow-ups via phone calls, clinic visits, and provide blood samples as required.

Inclusion Criteria

Body mass index (BMI) 17 to 35 inclusive at screening

I agree not to get any vaccines 28 days before or after study shots.

Provide written informed consent before initiation of any study procedures

Exclusion Criteria

History of hypersensitivity or severe reactions to previous vaccinations

I haven't taken long-term immune system drugs in the last 6 months.

Any medical disease or condition that, in the opinion of the participating site PI or appropriate sub-investigator, precludes study participation. Including significant respiratory disease (COPD), asthma that is not well controlled, significant cardiovascular disease, history of myocarditis or pericarditis, myocardial infarction, coronary artery bypass surgery or stent placement, or uncontrolled cardiac arrhythmia, neurological or neurodevelopmental conditions, ongoing malignancy or recent diagnosis of malignancy in the last five years excluding basal cell and squamous cell carcinoma of the skin, blood dyscrasias or significant disorder of coagulation, chronic liver disease, autoimmune disease, including localized or history of psoriasis or hypothyroidism without a defined non-autoimmune cause and immunodeficiency of any cause

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

1 visit (in-person)

Treatment

Participants receive 1 or 2 doses of HDT-321, with follow-up for adverse events and blood sample collection

8 weeks

10 visits (in-person) for Groups 1, 2, and 4; 9 visits (in-person) for Group 3

Follow-up

Participants are monitored for safety and effectiveness after treatment, including collection of adverse events and immunogenicity data

56 weeks

Combination of in-person visits and phone calls

What Are the Treatments Tested in This Trial?

Interventions

• HDT-321

Trial Overview The study tests the safety and immune response to three different doses (25ug, 10ug, 50ug) of HDT-321 vaccine against Crimean-Congo Hemorrhagic Fever. It aims to determine if it's safe and can protect against the virus with either a single or double dose regimen.

How Is the Trial Designed?

Group I: Group 4 Experimental Treatment 1 Intervention

Group 4 will include 12 participants who will receive a 50 ug two dose schedule of HDT-321 at day 1 and day 29.

Group II: Group 3 Experimental Treatment 1 Intervention

Group 3 will include 12 participants who will receive a 50 ug one dose schedule of HDT-321 at day 1.

Group III: Group 2 Experimental Treatment 1 Intervention

Group 2 will include 12 participants who will receive a 25 ug, two dose schedule of HDT-321 at day 1 and day 29.

Group IV: Group 1 Experimental Treatment 1 Intervention

Group 1 will include 12 participants who will receive a 10 ug two dose schedule of HDT-321 at day 1 and day 29.

Who Is Running the Clinical Trial?

HDT Bio

Lead Sponsor

Trials

2

Recruited

100+

BioAgilytix Labs, LLC

Collaborator

Trials

1

Recruited

50+

DFNet Research Inc.

Collaborator

Trials

2

Recruited

680+

Quest Laboratories

Collaborator

Trials

1

Recruited

50+

The University of Texas Medical Branch, Galveston

Collaborator

Trials

263

Recruited

55,400+

Technical Resources International, Inc. (TRI)

Collaborator

Trials

3

Recruited

2,300+

Clinical Trials of Texas, Inc.

Collaborator

Trials

3

Recruited

190+

Citations

1. clinicaltrials.gov clinicaltrials.gov/study/NCT06799013

Study Details | NCT06799013 | Safety and Immunogenicity ... The main questions it aims to answer are: Is HDT-321 safe to use; Does HDT-321 provide protection against Crimean-Congo hemorrhagic fever virus (CCHFV).

2. hdt.bio hdt.bio/2046-2/

FDA Greenlights HDT Bio's First-in-Class HDT-321 for the ... There, researchers showed that HDT-321 could protect against CCHF in several animal models. RML is a state-of-the-art biomedical research ...

3. pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov/40447644/

Single dose VSV-based vaccine protects mice against lethal ... Animals vaccinated with VSV-CCHFnp2 succumbed to lethal CCHFV challenge, while the VSV-CCHFgpc vaccine candidate afforded partial protection. In ...

4. smartpatients.com smartpatients.com/trials/NCT06799013

Safety and Immunogenicity of a Self-Amplifying RNA ... - Is HDT-321 safe to use. - Does HDT-321 provide protection against Crimean-Congo hemorrhagic fever virus (CCHFV). Researchers will record any ...

5. globalbiodefense.com globalbiodefense.com/2025/06/05/single-dose-vsv-vaccine-fully-protects-mice-against-crimean-congo-hemorrhagic-fever/

Single-Dose VSV Vaccine Fully Protects Mice Against ... A new NIH study shows a single-dose VSV-based vaccine offers full protection in mice against lethal Crimean-Congo hemorrhagic fever virus.

6. go.drugbank.com go.drugbank.com/conditions/DBCOND0170415

Crimean Congo Hemorrhagic Fever (DBCOND0170415) Associated Data ; NCT06799013. Safety and Immunogenicity of a Self-Amplifying RNA Vaccine Against Crimean-Congo Hemorrhagic Fever. HDT-321 ; NCT06684431. Study to ...

7. synapse.patsnap.com synapse.patsnap.com/drug/1a49237a17677da87175bb0321008012

HDT-321 - Drug Targets, Indications, Patents A Phase 1, Open Label, Dose-Escalation Study to Evaluate the Safety, Reactogenicity and Immunogenicity of a Nanoparticle Carrier-Formulated ...