Vaccine ResponsePhase 1NCT06821100
Thymalfasin (Thymosin Alpha 1; Ta1) as an Enhancer of Vaccine Response Among Older Adults Receiving Booster Doses of COVID-19 Vaccine
A Phase 1 study testing Thymalfasin (Thymosin alpha 1, Ta1) in people with Vaccine Response and COVID-19 Vaccine, run by The Methodist Hospital Research Institute at 1 site in United States.
Trial summary
The goal of this research is to learn more about ZADAXIN® (trade name; thymalfasin generic; Ta1 for short) and determine if Ta1 has any benefit in increasing the immune response to the COVID-19 vaccine. Ta1 has been shown to stimulate the immune system to fight infections. Read more about this study
- Who is it for?
- Ages 65 to 100 yearsHealthy volunteers can take part
- Conditions the study is for
- Vaccine Response, COVID-19 Vaccine, Immune Response to Covid 19 Vaccination
- What is being tested?
- Thymalfasin (Thymosin alpha 1, Ta1)
- Type of treatment
- Vaccines
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 75 participants
- Where
- 1 siteUnited States
- Study dates
- 2 Dec 2024to 1 Dec 2026
- 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 65 to 100 years
- All sexes
- Healthy volunteers accepted
- Older adult
Who may be able to join
- Subjects who meet all of the following criteria will be eligible to participate in the study:
- Age 65 or greater.
- Able and willing to provide informed consent or have consent provided by a legally authorized representative (LAR).
- Scheduled for SARS-CoV-2 mRNA vaccination booster dose.
- If a male subject, the subject must agree to use barrier contraception (ie, condoms) from Day 1 through 30 days following the last dose of study drug.
Who cannot join
- Subjects who meet any of the following criteria will be excluded from participation in the study.
- Laboratory related exclusion criteria should be assessed using historical records and lab results available in the subjects' electronic medical records.
- Hypoxemia for any reason, defined as either oxygen saturation (SpO2) ≤ 93% on room air or a requirement for supplemental oxygen support.
- Participants with one of the following:
- Acute liver failure defined as INR ≥ 1.5 and altered mental status in a patient without cirrhosis or pre-existing liver disease.
- Acute kidney failure defined as an increase in serum creatinine of ≥0.3 mg/dL within 48 hours or ≥50% within 7 days OR urine output of <0.5 mL/kg/hour for >6 hours
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- Heart failure with NYHA functional classification III or IV.
- Advanced cancer being treated with cytotoxic chemotherapy.
- Participants have end stage renal disease requiring hemodialysis or peritoneal dialysis, or chronic kidney disease with GFR < 30 mL/min/1.73m2
- Participants with a known history of cirrhosis and Child-Pugh score B or C.
- Participants who are moderately or severely immunocompromised defined as:
- Are receiving active treatment for solid tumor and hematologic malignancies.
- Have hematologic malignancies (e.g., chronic lymphocytic lymphoma, non Hodgkin lymphoma, multiple myeloma, acute leukemia) and are known to have poor responses to COVID-19 vaccines, regardless of the treatment status for the hematologic malignancy.
- Received a solid-organ or islet transplant and are receiving immunosuppressive therapy.
- Received chimeric antigen receptor T cell (CAR T-cell) therapy or a hematopoietic cell transplant (HCT) and are within 2 years of transplantation or are receiving immunosuppressive therapy.
- Have a moderate or severe primary immunodeficiency (e.g., severe combined immunodeficiency, DiGeorge syndrome, Wiskott-Aldrich syndrome, common variable immunodeficiency disease).
- Have advanced or untreated HIV infection (defined as people with HIV and CD4 T lymphocyte cell counts <200 cells/mm3, a history of an AIDS-defining illness without immune reconstitution, or clinical manifestations of symptomatic HIV).
- Are receiving active treatment with high-dose corticosteroids (i.e., ≥20 mg prednisone or equivalent per day for ≥2 weeks), alkylating agents, antimetabolites, transplant-related immunosuppressive drugs, cancer chemotherapeutic agents classified as severely immunosuppressive, or immunosuppressive or immunomodulatory biologic agents (e.g., B cell-depleting agents).
- Participants with uncontrolled autoimmune or rheumatologic disease.
- Participants have received 6 doses or more of the COVID-19 vaccine. (Removed in Amendment 3)
- Participants with a history of myocarditis, pericarditis, or myopericarditis.
- Participants with a history of anemia or bleeding disorders. For anemia, the exclusion criterion will be met if any of the following are true:
- Active anemia, defined as Hb<9 g/dL within 30 days prior to screening, ii. Unresolved anemia: Hb<11 g/dL (females) or <12 g/dL (males) during any window of >=3 months in the past year AND no evidence of measures of correction (e.g. iron supplementation, transfusion) in the same time window, iii. High risk etiologies of anemia: myelodysplastic syndromes, aplastic anemia, hemoglobinopathies (e.g., sickle cell trait, sickle cell anemia), anemia due to malignancy, anemia due to chronic kidney disease, anemia due to untreated nutritional deficiencies, anemia due to toxic exposures (e.g., chronic lead poisoning), or any other high-risk etiology as determined by the study investigator,
- Anemia with intensive recent (within 6 months) interventions, including red blood cell transfusion or IV iron infusion, v. Symptomatic anemia in the year prior to screening, including shortness of breath, exercise intolerance, type 3 myocardial infarction, if clearly attributed to the anemia.
- Participants who have precautions or contraindications to COVID-19 vaccine per the CDC interim clinical considerations for use of COVID-19 vaccines, including the following:
- History of a severe allergic reaction (e.g., anaphylaxis) after a previous dose or to a component of the COVID-19 vaccine
- History of a diagnosed non-severe allergy to a component of the COVID-19 vaccine
- History of a non-severe, immediate (onset less than 4 hours) allergic reaction after administration of a previous dose of one COVID-19 vaccine type
- Moderate or severe acute illness, with or without fever
- History of multisystem inflammatory syndrome in adults
- History of myocarditis or pericarditis within 3 weeks after a dose of any COVID19 vaccine
- History of allergy or intolerance to Ta1.
- SARS-CoV-2 or other infection, during screening.
- SARS-CoV-2 mRNA or other SARS-CoV-2 vaccination during the previous 6 months.
- Participants who have dermatologic conditions that could affect local solicited adverse event (AE) assessment (e.g., psoriasis patches affecting skin over the sites of injection).
- Any medical condition that, in the judgement of the Investigator, could interfere with treatment or compliance with the protocol.
- Has received an investigational drug within the previous 30 days.
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
Houston Methodist Hospital
Houston, Texas, 77030
Eleftherios Mylonakis, MD, PhD, 713-441-1576, emylonakis@houstonmethodist.org
About this study
The goal of this research is to learn more about ZADAXIN® (trade name; thymalfasin generic; Ta1 for short) and determine if Ta1 has any benefit in increasing the immune response to the COVID-19 vaccine. Ta1 has been shown to stimulate the immune system to fight infections.
This research study will test the safety and possible harms of Ta1 when it is given to people at different dose levels before COVID-19 vaccination.
- Being tested
- Thymalfasin (Thymosin alpha 1, Ta1)
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Thymalfasin (Thymosin alpha 1, Ta1)Drug
Ta1 is a naturally occurring peptide that has been evaluated for its immunomodulatory activities and related therapeutic potential in several conditions and diseases. Ta1 has been shown to provide increased response to vaccines.
| Study group | Role | What they receive |
|---|---|---|
| Control | No intervention | No Ta1 prior to vaccination |
| Treatment arm A | Experimental | A 4.8 mg dose of Ta1 (dose of 1.6 mg in 1 mL of diluent X3) on Day 0, followed by vaccination Receives: Drug: Thymalfasin (Thymosin alpha 1, Ta1) |
| Treatment arm B | Experimental | A 4.8 mg dose of Ta1 (dose of 1.6 mg in 1 mL of diluent X3) on Day 0 and Day 3, followed by vaccination Receives: Drug: Thymalfasin (Thymosin alpha 1, Ta1) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Incidence of Treatment-Emergent Adverse Events [Safety and Tolerability]
The primary objective is to evaluate the safety and tolerability of different treatment regimens of Ta1 before vaccination with a SARS-CoV-2 mRNA vaccine. This will be measured by:
- The incidence and severity of adverse events (AEs) following treatment
Measured: 52 weeks
Secondary outcomes (3)
Levels of neutralizing and non-neutralizing antibodies
Levels of neutralizing and non-neutralizing antibodies. Data will be summarized descriptively for each treatment arm and no formal hypothesis testing is planned
Measured: 24 weeks
Neutralizing activity to SARS-CoV-2
Neutralizing activity to SARS-CoV-2, measured using a using a pseudovirus neutralization assay. Data will be summarized descriptively for each treatment arm and no formal hypothesis testing is planned
Measured: 24 weeks
T cell response
T cell response. Data will be summarized descriptively for each treatment arm and no formal hypothesis testing is planne
Measured: 24 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted11 Feb 2025
- Study start2 Dec 2024
- Primary completion1 Dec 2026 (estimated)
- Study completion1 Dec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Vaccine ResponseStudies of the same condition, open and under way.
- More trials run by The Methodist Hospital Research InstituteThe sponsor's other registered studies.
- 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
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- A randomized open label Phase 1 study to evaluate the safety and tolerability of different treatment regimens of Ta1 before vaccination with a SARS-CoV-2 mRNA vaccine. Study participants will be randomized in a 1:1:1 ratio to one of the following treatment groups: * No Ta1 prior to vaccination (Control) * A 4.8 mg dose of Ta1 (dose of 1.6 mg in 1 mL of diluent X3) on Day 0, followed by vaccination (Treatment arm A) * A 4.8 mg dose of Ta1 (dose of 1.6 mg in 1 mL of diluent X3) on Day 0 and Day 3, followed by vaccination (Treatment arm B) * All participants will receive the same mRNA SARS-CoV-2 mRNA vaccine (Moderna or Pfizer) for consistency.
- Masking
- None (open label)
- Enrolment
- 75 participants (estimated)
Sponsor and investigators
- Lead sponsor
- The Methodist Hospital Research Institute
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06821100
- Sponsor's protocol ID
- PRO00037612
- Status last verified
- Jul 2026
- First submitted
- 15 Jan 2025
- Last updated
- 16 Jul 2026
- 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 16 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Thymalfasin (Thymosin Alpha 1; Ta1) as an Enhancer of Vaccine Response Among Older Adults Receiving Booster Doses of COVID-19 Vaccine
- ClinicalTrials.gov ID
- NCT06821100
- Acronym / sponsor ID
- PRO00037612
- Phase
- Phase 1
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 75 participants (estimated)
- Lead sponsor
- The Methodist Hospital Research InstituteUniversity, hospital or other
- Study start
- 2 Dec 2024 (actual)
- Primary completion
- 1 Dec 2026 (estimated)
- Study completion
- 1 Dec 2026 (estimated)
- First posted
- 11 Feb 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 research is to learn more about ZADAXIN® (trade name; thymalfasin generic; Ta1 for short) and determine if Ta1 has any benefit in increasing the immune response to the COVID-19 vaccine. Ta1 has been shown to stimulate the immune system to fight infections.
This research study will test the safety and possible harms of Ta1 when it is given to people at different dose levels before COVID-19 vaccination.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 3
- Model description
- A randomized open label Phase 1 study to evaluate the safety and tolerability of different treatment regimens of Ta1 before vaccination with a SARS-CoV-2 mRNA vaccine. Study participants will be randomized in a 1:1:1 ratio to one of the following treatment groups: * No Ta1 prior to vaccination (Control) * A 4.8 mg dose of Ta1 (dose of 1.6 mg in 1 mL of diluent X3) on Day 0, followed by vaccination (Treatment arm A) * A 4.8 mg dose of Ta1 (dose of 1.6 mg in 1 mL of diluent X3) on Day 0 and Day 3, followed by vaccination (Treatment arm B) * All participants will receive the same mRNA SARS-CoV-2 mRNA vaccine (Moderna or Pfizer) for consistency.
| Arm | Type | Receives |
|---|---|---|
| Control | No intervention | –No Ta1 prior to vaccination |
| Treatment arm A | Experimental | Drug: Thymalfasin (Thymosin alpha 1, Ta1)A 4.8 mg dose of Ta1 (dose of 1.6 mg in 1 mL of diluent X3) on Day 0, followed by vaccination |
| Treatment arm B | Experimental | Drug: Thymalfasin (Thymosin alpha 1, Ta1)A 4.8 mg dose of Ta1 (dose of 1.6 mg in 1 mL of diluent X3) on Day 0 and Day 3, followed by vaccination |
Who may qualify
- Ages
- 65 to 100 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Older adult
Key inclusion criteria (5 listed)
- Subjects who meet all of the following criteria will be eligible to participate in the study:
- Age 65 or greater.
- Able and willing to provide informed consent or have consent provided by a legally authorized representative (LAR).
- Scheduled for SARS-CoV-2 mRNA vaccination booster dose.
- If a male subject, the subject must agree to use barrier contraception (ie, condoms) from Day 1 through 30 days following the last dose of study drug.
Key exclusion criteria (37 listed)
- Subjects who meet any of the following criteria will be excluded from participation in the study.
- Laboratory related exclusion criteria should be assessed using historical records and lab results available in the subjects' electronic medical records.
- Hypoxemia for any reason, defined as either oxygen saturation (SpO2) ≤ 93% on room air or a requirement for supplemental oxygen support.
- Participants with one of the following:
- Advanced cancer being treated with cytotoxic chemotherapy.
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 |
|---|---|---|
| Thymalfasin (Thymosin alpha 1, Ta1)Ta1 is a naturally occurring peptide that has been evaluated for its immunomodulatory activities and related therapeutic potential in several conditions and diseases. Ta1 has been shown to provide increased response to vaccines. | Drug | Treatment arm A, Treatment arm B |
Primary outcome
Incidence of Treatment-Emergent Adverse Events [Safety and Tolerability]
Time frame: 52 weeks
The primary objective is to evaluate the safety and tolerability of different treatment regimens of Ta1 before vaccination with a SARS-CoV-2 mRNA vaccine. This will be measured by: - The incidence and severity of adverse events (AEs) following treatment
3 secondary outcomes
Levels of neutralizing and non-neutralizing antibodies
Time frame: 24 weeks
Neutralizing activity to SARS-CoV-2
Time frame: 24 weeks
T cell response
Time frame: 24 weeks
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 16 Jul 2026.
- Individual participant dataSharing planned: No
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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.
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 Thymalfasin (Thymosin alpha 1, Ta1) in people with Vaccine Response and COVID-19 Vaccine, run by The Methodist Hospital Research Institute 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 5 inclusion and 37 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 16 Jul 2026. 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 Eleftherios Mylonakis, MD, PhD (7134411576, emylonakis@houstonmethodist.org), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Incidence of Treatment-Emergent Adverse Events [Safety and Tolerability] (time frame: 52 weeks). 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 16 Jul 2026.