VaccinePhase 1NCT06799013
Safety and Immunogenicity of a Self-Amplifying RNA Vaccine Against Crimean-Congo Hemorrhagic Fever
A Phase 1 study testing 10 ug HDT 321, 25ug HDT-321 and 50ug HDT-321 in people with Vaccine and Crimean-Congo Hemorrhagic Fever, run by HDT Bio at 1 site in United States.
Trial summary
The goal of this clinical trial is to assess the safety, tolerability and immunogenicity of three dosage levels, and a single or two-dose administration regimen, of the investigational HDT-321 product administered intra-muscularly. Read more about this study
- Who is it for?
- Ages 18 to 64 yearsHealthy volunteers can take part
- Conditions the study is for
- Vaccine, Crimean-Congo Hemorrhagic Fever
- What is being tested?
- 10 ug HDT 321, 25ug HDT-321 and 50ug HDT-321
- Type of treatment
- Vaccines
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 48 participants
- Where
- 1 siteUnited States
- Study dates
- 10 Jul 2025to Jul 2027
- Phase
- Phase 1
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 64 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Males and non-pregnant females 18 to 64 years of age at the time of signing the ICF.
- Body mass index (BMI) 17 to 35 inclusive at screening.
- Considered by the PI or designee to be in good general health as determined by medical history, physical examination, vital sign measurements*, and clinical laboratory assessments conducted no more than 30 days prior to the first study injection administration.
- Screening laboratory values within the laboratory reference ranges or considered non-clinically significant (NCS) if within Grade 1 severity on the toxicity grading scale.
- Negative human immunodeficiency virus (HIV) 1/2 antibody, hepatitis B surface antigen (HBsAg), and hepatitis C virus (HCV) antibody.
- Women of childbearing potential must agree to use or have practiced true abstinence or use at least one acceptable primary form of contraception3 for at least 30 days prior to the first injection and for 60 days after the last injection. Female participants of childbearing potential must have a negative serum pregnancy test at screening and a negative urine pregnancy test on the day of and prior to each study injection.
Show all 10Show fewer
- Able to understand and comply with planned study procedures and willing to be available for all study required procedures, visits, and telephone calls for the duration of the study.
- Provide written informed consent before initiation of any study procedures.
- Willing to abstain from donating whole blood or blood derivatives 30 days prior to screening and for the duration of the study.
- Willing to refrain from receiving any licensed vaccine within 28 days prior to and after scheduled study injections.
Who cannot join
- Any medical disease or condition that, in the opinion of the participating site PI or appropriate sub-investigator, precludes study participation. Including Acute, subacute, intermittent, or chronic medical diseases or conditions that would place the subject at an unacceptable risk of injury, render the subject unable to meet the requirements of the protocol, or may interfere with the evaluation of responses or the subject's successful completion of the trial. Significant respiratory disease (COPD) requiring daily medications, 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, including fatty liver, autoimmune disease, including localized or history of psoriasis or hypothyroidism without a defined non-autoimmune cause and Immunodeficiency of any cause.
- Abnormal screening electrocardiogram (ECG)
- History of hypersensitivity or severe reactions to previous vaccinations
- History of hypersensitivity or severe reactions to products known to contain polyethylene glycol (PEG).
- Allergy to antibiotics structurally similar to kanamycin (including but not limited to neomycin, streptomycin, tobramycin, and gentamycin).
- Chronic administration (defined as more than 14 days in total) of immunosuppressants or other immunemodifying drugs within 6 months prior to the first study injection (for corticosteroids: prednisone ≥20 mg/day or equivalent). Intra-articular, inhaled, nasal, and topical steroids are allowed.
Show all 16Show fewer
- Received immunoglobulins or any blood products within 60 days prior to enrollment/Day 1.
- Donated blood products within 30 days prior to enrollment/Day 1.
- Received an investigational or non-registered medicinal product within 30 days prior to screening.
- Currently enrolled, or plan to participate, in another clinical trial with an investigational agent to be received during the study period.
- Received or plans to receive any non-study vaccine within 28 days before and after each study injection.
- Febrile illness*, as determined by the participating site PI or appropriate sub-investigator, with or without fever (oral temperature ≥38.0°C/100.4°F), within 24 hours prior to each study injection.
- Current heavy smoking/vaping (defined as 1 pack or more of cigarettes a day or vaping equivalent*). *1-2 mL of 20 mg/mL of nicotine salt
- Known or suspected alcohol or illicit drug abuse within the past 12 months prior to Study Day 1.
- Breastfeeding or plans to breastfeed from the time of the first vaccination through 60 days after the last study injection.
- Participants unlikely to cooperate with the requirements of the study protocol.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
Flourish Research San Antonio (Clinical Trials of Texas)
San Antonio, Texas, 78229
Jessie Williams, 210-949-0122 ext. 179, jwilliams@flourishresearch.com
Barbara Corral, DNP, 210-949-0122 ext. 151, BCorral@flourishresearch.com
About this study
Official title: A Phase 1, Open Label, Dose-Escalation Study to Evaluate the Safety, Reactogenicity and Immunogenicity of a Nanoparticle Carrier-Formulated Self-Amplifying RNA Vaccine Against Crimean-Congo Hemorrhagic Fever (HDT-321) in Healthy Adults
The goal of this clinical trial is to assess the safety, tolerability and immunogenicity of three dosage levels, and a single or two-dose administration regimen, of the investigational HDT-321 product administered intra-muscularly. 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)
Read more
Researchers will record any adverse events and test blood samples to see if HDT-321 is safe and works to protect participants against Crimean-Congo hemorrhagic fever virus (CCHFV)
Participants will:
- Receive 1 or 2 doses of HDT-321
- Complete a memory aid and measurements for 7 days after receiving each dose of HDT-321
- Be followed throughout the study using phone calls and clinic visits to check for and record adverse events
- Provide blood samples at specific study visits
Read the detailed description
This is an open-label, dose-escalation, first-in-human study to evaluate the safety, reactogenicity and immunogenicity of the investigational product HDT-321 in approximately 48 healthy adults aged 18-64 years.
Four groups of 12 participants at three dosage levels will be sequentially recruited in the study, starting with the lowest dose. Groups 1, 2 and 4 will receive 2 doses and group 3 will receive 1 dose of HDT-321.
Study progression and dose escalation will occur according to the following:
Group 1 (10 μg): Three sentinel participants will be initially enrolled and followed for 7 days post-first study injection for safety assessment by predetermined objective criteria. If none of the pre-defined halting rules are met, as confirmed by the Safety Review Team (SRT), enrollment of the remaining participants of the group will proceed. In addition, available safety data for 7 days post-second study injection will be evaluated in the sentinel group prior to administering the second injection of the remaining participants of Group 1. Available safety data for 7 days post-first study injection of all participants will be reviewed by the SRT. If none of the pre-defined halting rules are met and no safety concerns have been identified, enrollment of Group 2 participants will proceed.
Group 2 (25 μg): In a similar fashion, three sentinel participants will be initially enrolled and followed for 7 days post-first study injection for safety assessment by predetermined objective criteria. If none of the pre-defined halting rules are met, as confirmed by the SRT, enrollment of the remaining participants of the group will proceed. In addition, available safety data for 7 days post second study injection will be evaluated in the sentinel group prior to administering the second injection of the remaining participants of Group 2. Available safety data for 7 days post-first study injection of all Group 1 and 2 participants along with any available post-second injection from Group 1 participants will be reviewed by the SRT. If none of the pre-defined halting rules are met and no safety concerns have been identified, enrollment of Groups 3 and 4 participants will proceed.
Groups 3 and 4 (50 μg): the same procedure with initial enrollment of three sentinel participants will be followed as outlined above, prior to enrollment of the remaining participants of Group 3 and all of Group 4. In addition, the available data 7 days post-first injection of the entire Group 3 and 4 along with available post-second injection data from Group 1 and 2 will be reviewed prior to administering the second dose of Group 4 participants.
Blood samples will be collected from all participants in the study. Participants in groups 1, 2 and 4 will provide samples at screening and 8 additional visits. Participants in group 3 will provide samples at screening and 7 additional visits.
Participants will be requested to attend a combination of in person clinic visits and phone calls. Participants in groups 1, 2 and 4 will have 2 phone calls and 10 in-clinic visits. Two of the clinic visits will include administration of HDT-321 via IM injections. Participants in cohort 3 will have 1 phone call and 9 in-clinic visits. One of the clinic visits will include administration of HDT-321 via IM injection.
Protocol-defined solicited local and systemic AEs will be collected for 7 days following each study injection via memory aid. Other AEs will be collected for 28 days following each study injection. SAEs, AESIs, MAAEs and NOCDs will be collected from the first study injection through their entire study participation.
- Conditions
- Vaccine, Crimean-Congo Hemorrhagic Fever
- Being tested
- 10 ug HDT 321, 25ug HDT-321, 50ug HDT-321
- Keywords
- Vaccine, Healthy, 18-64, Male, Female, Preventative
- Medical subject headings
- Hemorrhagic Fever, Crimean
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
10 ug HDT 321Biological
HDT-321 Investigational Vaccine (a Nanoparticle Carrier-Formulated self-amplifying RNA encoding the NP of CCHFV)
25ug HDT-321Biological
HDT-321 Investigational Vaccine (a Nanoparticle Carrier-Formulated self-amplifying RNA encoding the NP of CCHFV)
50ug HDT-321Biological
HDT-321 Investigational Vaccine (a Nanoparticle Carrier-Formulated self-amplifying RNA encoding the NP of CCHFV)
| Study group | Role | What they receive |
|---|---|---|
| Group 1 | Experimental | Group 1 will include 12 participants who will receive a 10 ug two dose schedule of HDT-321 at day 1 and day 29. Receives: Biological: 10 ug HDT 321 |
| Group 2 | Experimental | Group 2 will include 12 participants who will receive a 25 ug, two dose schedule of HDT-321 at day 1 and day 29. Receives: Biological: 25ug HDT-321 |
| Group 3 | Experimental | Group 3 will include 12 participants who will receive a 50 ug one dose schedule of HDT-321 at day 1. Receives: Biological: 50ug HDT-321 |
| Group 4 | Experimental | Group 4 will include 12 participants who will receive a 50 ug two dose schedule of HDT-321 at day 1 and day 29. Receives: Biological: 50ug HDT-321 |
What is being measured
The primary outcome is the main question the study is designed to answer.
Solicited local and systemic adverse events (AEs)
Frequency and grade of solicited local and systemic AEs during the 7-day follow-up period after each study injection (i.e. the day of administration and 6 subsequent days).
Measured: Day 1-7 post administration
Unsolicited study product related adverse events
Frequency and grade of unsolicited study product related AEs reported during the 28-day follow-up period after each study injection.
Measured: Day 1-28 post administration
Laboratory abnormalities
Occurrence of laboratory abnormalities at 7 days post injection visit (increased or decreased outside normal ranges, as determined by the FDA Guidance for Industry Toxicity Grading Scale for Healthy Adults Enrolled in Preventive Vaccine Clinical Trials, 2007)
Measured: Day 1-7 post administration
Serious AEs, AEs of Special Interest, Medically Attended AEs, and New-Onset of Chronic Diseases
Frequency and grade of Serious AEs (SAEs), AEs of Special Interest (AESIs), Medically-Attended AEs (MAAEs), and New-Onset of Chronic Diseases (NOCDs) during the duration of participation in the study.
Measured: Day 1 to end of study participation (Day 394)
Secondary outcomes (1)
Immunogenicity of HDT-321
Evaluate the immunogenicity of HDT-321 as measured by IgG ELISA to the CCHFV NP measured 28 and 56 days after each injection. Using geometric mean titers (GMTs) of circulating antibodies against CCHFV NP through Day 57 along with seroconversion rate for anti-NP antibody through Day 57.
Measured: Day 1 to Day 57
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 Jan 2025
- Study start10 Jul 2025
- Primary completionDec 2026 (estimated)
- Study completionJul 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for VaccineStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 1
- Primary purpose
- Prevention
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Model description
- Four groups of 12 participants across three dose levels will be sequentially recruited in the study, starting with the lowest dose. The three dose levels and four treatment groups are outlined below. Group 1: 12 participants receive 10 μg vaccinations on Day 1 and Day 29 Group 2: 12 participants receive 25 μg vaccinations on Day 1 and Day 29 Group 3: 12 participants receive 50 μg vaccination on Day 1 Group 4: 12 participants receive 50 μg vaccinations on Day 1 and Day 29
- Masking
- None (open label)
- Enrolment
- 48 participants (estimated)
Sponsor and investigators
- Lead sponsor
- HDT Bio
- Sponsor type
- Industry (pharma, biotech, devices)
- Collaborators
- DFNet Research Inc., Technical Resources International, Inc., BioAgilytix Labs, LLC, The University of Texas Medical Branch, Galveston, Clinical Trials of Texas, Inc., Quest Laboratories
- Responsible party
- Sponsor
- Investigators
- Malcolm Duthie, PhD, Study director, HDT Bio
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06799013
- Sponsor's protocol ID
- HDT-321-001
- Other IDs
- W15QKN-16-9-1002 / 23-86397-01
- Status last verified
- Jul 2025
- First submitted
- 16 Jan 2025
- Last updated
- 28 Jul 2025
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 28 Jul 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 1, Open Label, Dose-Escalation Study to Evaluate the Safety, Reactogenicity and Immunogenicity of a Nanoparticle Carrier-Formulated Self-Amplifying RNA Vaccine Against Crimean-Congo Hemorrhagic Fever (HDT-321) in Healthy Adults
- ClinicalTrials.gov ID
- NCT06799013
- Acronym / sponsor ID
- HDT-321-001
- Conditions
- Vaccine, Crimean-Congo Hemorrhagic Fever
- Keywords
- Vaccine, Healthy, 18-64, Male, Female, Preventative
- Phase
- Phase 1
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 48 participants (estimated)
- Lead sponsor
- HDT BioIndustry (pharma, biotech, devices)
- Collaborators
- DFNet Research Inc., Technical Resources International, Inc., BioAgilytix Labs, LLC, The University of Texas Medical Branch, Galveston, Clinical Trials of Texas, Inc., Quest Laboratories
- Study start
- 10 Jul 2025 (actual)
- Primary completion
- Dec 2026 (estimated)
- Study completion
- Jul 2027 (estimated)
- First posted
- 29 Jan 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The goal of this clinical trial is to assess the safety, tolerability and immunogenicity of three dosage levels, and a single or two-dose administration regimen, of the investigational HDT-321 product administered intra-muscularly. 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)
Researchers will record any adverse events and test blood samples to see if HDT-321 is safe and works to protect participants against Crimean-Congo hemorrhagic fever virus (CCHFV)
Participants will:
- Receive 1 or 2 doses of HDT-321
- Complete a memory aid and measurements for 7 days after receiving each dose of HDT-321
- Be followed throughout the study using phone calls and clinic visits to check for and record adverse events
- Provide blood samples at specific study visits
Detailed description
This is an open-label, dose-escalation, first-in-human study to evaluate the safety, reactogenicity and immunogenicity of the investigational product HDT-321 in approximately 48 healthy adults aged 18-64 years.
Four groups of 12 participants at three dosage levels will be sequentially recruited in the study, starting with the lowest dose. Groups 1, 2 and 4 will receive 2 doses and group 3 will receive 1 dose of HDT-321.
Study progression and dose escalation will occur according to the following:
Group 1 (10 μg): Three sentinel participants will be initially enrolled and followed for 7 days post-first study injection for safety assessment by predetermined objective criteria. If none of the pre-defined halting rules are met, as confirmed by the Safety Review Team (SRT), enrollment of the remaining participants of the group will proceed. In addition, available safety data for 7 days post-second study injection will be evaluated in the sentinel group prior to administering the second injection of the remaining participants of Group 1. Available safety data for 7 days post-first study injection of all participants will be reviewed by the SRT. If none of the pre-defined halting rules are met and no safety concerns have been identified, enrollment of Group 2 participants will proceed.
Group 2 (25 μg): In a similar fashion, three sentinel participants will be initially enrolled and followed for 7 days post-first study injection for safety assessment by predetermined objective criteria. If none of the pre-defined halting rules are met, as confirmed by the SRT, enrollment of the remaining participants of the group will proceed. In addition, available safety data for 7 days post second study injection will be evaluated in the sentinel group prior to administering the second injection of the remaining participants of Group 2. Available safety data for 7 days post-first study injection of all Group 1 and 2 participants along with any available post-second injection from Group 1 participants will be reviewed by the SRT. If none of the pre-defined halting rules are met and no safety concerns have been identified, enrollment of Groups 3 and 4 participants will proceed.
Groups 3 and 4 (50 μg): the same procedure with initial enrollment of three sentinel participants will be followed as outlined above, prior to enrollment of the remaining participants of Group 3 and all of Group 4. In addition, the available data 7 days post-first injection of the entire Group 3 and 4 along with available post-second injection data from Group 1 and 2 will be reviewed prior to administering the second dose of Group 4 participants.
Blood samples will be collected from all participants in the study. Participants in groups 1, 2 and 4 will provide samples at screening and 8 additional visits. Participants in group 3 will provide samples at screening and 7 additional visits.
Participants will be requested to attend a combination of in person clinic visits and phone calls. Participants in groups 1, 2 and 4 will have 2 phone calls and 10 in-clinic visits. Two of the clinic visits will include administration of HDT-321 via IM injections. Participants in cohort 3 will have 1 phone call and 9 in-clinic visits. One of the clinic visits will include administration of HDT-321 via IM injection.
Protocol-defined solicited local and systemic AEs will be collected for 7 days following each study injection via memory aid. Other AEs will be collected for 28 days following each study injection. SAEs, AESIs, MAAEs and NOCDs will be collected from the first study injection through their entire study participation.
Study design
- Primary purpose
- Prevention
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 4
- Model description
- Four groups of 12 participants across three dose levels will be sequentially recruited in the study, starting with the lowest dose. The three dose levels and four treatment groups are outlined below. Group 1: 12 participants receive 10 μg vaccinations on Day 1 and Day 29 Group 2: 12 participants receive 25 μg vaccinations on Day 1 and Day 29 Group 3: 12 participants receive 50 μg vaccination on Day 1 Group 4: 12 participants receive 50 μg vaccinations on Day 1 and Day 29
| Arm | Type | Receives |
|---|---|---|
| Group 1 | Experimental | Biological: 10 ug HDT 321Group 1 will include 12 participants who will receive a 10 ug two dose schedule of HDT-321 at day 1 and day 29. |
| Group 2 | Experimental | Biological: 25ug HDT-321Group 2 will include 12 participants who will receive a 25 ug, two dose schedule of HDT-321 at day 1 and day 29. |
| Group 3 | Experimental | Biological: 50ug HDT-321Group 3 will include 12 participants who will receive a 50 ug one dose schedule of HDT-321 at day 1. |
| Group 4 | Experimental | Biological: 50ug HDT-321Group 4 will include 12 participants who will receive a 50 ug two dose schedule of HDT-321 at day 1 and day 29. |
Who may qualify
- Ages
- 18 to 64 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (10 listed)
- Males and non-pregnant females 18 to 64 years of age at the time of signing the ICF.
- Body mass index (BMI) 17 to 35 inclusive at screening.
- Considered by the PI or designee to be in good general health as determined by medical history, physical examination, vital sign measurements*, and clinical laboratory assessments conducted no more than 30 days prior to the first study injection administration.
- Screening laboratory values within the laboratory reference ranges or considered non-clinically significant (NCS) if within Grade 1 severity on the toxicity grading scale.
- Negative human immunodeficiency virus (HIV) 1/2 antibody, hepatitis B surface antigen (HBsAg), and hepatitis C virus (HCV) antibody.
Key exclusion criteria (16 listed)
- Any medical disease or condition that, in the opinion of the participating site PI or appropriate sub-investigator, precludes study participation. Including Acute, subacute, intermittent, or chronic medical diseases or conditions that would place the subject at an unacceptable risk of injury, render the subject unable to meet the requirements of the protocol, or may interfere with the evaluation of responses or the subject's successful completion of the trial. Significant respiratory disease (COPD) requiring daily medications, 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, including fatty liver, autoimmune disease, including localized or history of psoriasis or hypothyroidism without a defined non-autoimmune cause and Immunodeficiency of any cause.
- Abnormal screening electrocardiogram (ECG)
- History of hypersensitivity or severe reactions to previous vaccinations
- History of hypersensitivity or severe reactions to products known to contain polyethylene glycol (PEG).
- Allergy to antibiotics structurally similar to kanamycin (including but not limited to neomycin, streptomycin, tobramycin, and gentamycin).
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| 10 ug HDT 321HDT-321 Investigational Vaccine (a Nanoparticle Carrier-Formulated self-amplifying RNA encoding the NP of CCHFV) | Biological | Group 1 |
| 25ug HDT-321HDT-321 Investigational Vaccine (a Nanoparticle Carrier-Formulated self-amplifying RNA encoding the NP of CCHFV) | Biological | Group 2 |
| 50ug HDT-321HDT-321 Investigational Vaccine (a Nanoparticle Carrier-Formulated self-amplifying RNA encoding the NP of CCHFV) | Biological | Group 3, Group 4 |
Primary outcome
Solicited local and systemic adverse events (AEs)
Time frame: Day 1-7 post administration
Frequency and grade of solicited local and systemic AEs during the 7-day follow-up period after each study injection (i.e. the day of administration and 6 subsequent days).
Unsolicited study product related adverse events
Time frame: Day 1-28 post administration
Frequency and grade of unsolicited study product related AEs reported during the 28-day follow-up period after each study injection.
Laboratory abnormalities
Time frame: Day 1-7 post administration
Occurrence of laboratory abnormalities at 7 days post injection visit (increased or decreased outside normal ranges, as determined by the FDA Guidance for Industry Toxicity Grading Scale for Healthy Adults Enrolled in Preventive Vaccine Clinical Trials, 2007)
Serious AEs, AEs of Special Interest, Medically Attended AEs, and New-Onset of Chronic Diseases
Time frame: Day 1 to end of study participation (Day 394)
Frequency and grade of Serious AEs (SAEs), AEs of Special Interest (AESIs), Medically-Attended AEs (MAAEs), and New-Onset of Chronic Diseases (NOCDs) during the duration of participation in the study.
1 secondary outcome
Immunogenicity of HDT-321
Time frame: Day 1 to Day 57
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 28 Jul 2025.
- Individual participant dataSharing planned: No
Related trials for Vaccine
Not yet recruitingPhase 2/3
A Pivotal Safety and Immunogenicity GBS-NN/NN2 Vaccine Maternal Immunisation Trial
Streptococcus Agalactiae Infection, Neonatal Sepsis
Active, not recruitingPhase 1
A Safety and Immunogenicity Trial of OCU500, ChAd36 Vector Encoding SARS-CoV-2 Spike Vaccine Via Intranasal and Inhalational Routes in Previously Vaccinated Adults
COVID-19
RecruitingPhase 3
Study to Learn About a Respiratory Syncytial Virus Vaccine in Children at High Risk of RSV Disease
Respiratory Syncytial Virus (RSV)
RecruitingPhase 2
BPL-1357 Against H1N1 Influenza Virus Challenge
Influenza, Human
Not yet recruitingPhase 1/2
Clinical Trial to Assess the Safety, Tolerability, Reactogenicity, and Immunogenicity of a 10 Valent Human Papillomavirus Virus (10vHPV) Vaccine
Human Papillomavirus Infection
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Malcolm Duthie, PhD study director
HDT Bio
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1 study testing 10 ug HDT 321, 25ug HDT-321 and 50ug HDT-321 in people with Vaccine and Crimean-Congo Hemorrhagic Fever, run by HDT Bio at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 10 inclusion and 16 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 28 Jul 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact James Keary (206-567-8230, james.keary@hdt.bio), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Solicited local and systemic adverse events (AEs) (time frame: Day 1-7 post administration). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 28 Jul 2025.