Thymosin Alpha 1 to Prevent COVID-19 Infection in Renal Dialysis Patients (Ta1)

April 15, 2026 updated by: William B. Ershler, MD

A Pilot Trial of Thymalfasin (Ta1) to Prevent COVID-19 Infection in Renal Dialysis Patients

Thymalfasin (thymosin alpha 1 or Ta1), the active pharmaceutical ingredient in ZADAXIN® injection, is a 28-amino acid synthetic peptide, identical to natural Ta1 produced by the thymus gland. Ta1 is a biological response modifier which activates various cells of the immune system, and is therefore expected to have clinical benefits in disorders where immune responses are impaired or ineffective, including acute and chronic viral and bacterial infections, cancers, and vaccine non-responsiveness. Patients with end-stage renal disease (ESRD) on hemodialysis, in addition to their intrinsic kidney disease and frequent burden of comorbidities, also have increased risk of exposure to communicable diseases as they are treated several times each week at hemodialysis centers with several other patients and clinic staff in attendance. The majority of patients are over 60 years of age and many are receiving immunosuppressive medications. Accordingly, ESRD patients are particularly susceptible to COVID-19 infection. Ta1 has been shown to be safely administered to hemodialysis patients. It is our hypothesis that a course of Ta1 administered to individuals with ESRD will reduce the rate and severity of infection with COVID-19.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Patients with end-stage renal disease (ESRD) on hemodialysis, in addition to their intrinsic kidney disease and frequent burden of comorbidities, also have increased risk of exposure to communicable diseases as they are treated several times each week at hemodialysis centers with several other patients and clinic staff in attendance. The majority of patients are over 60 years of age and many are receiving immunosuppressive medications. Accordingly, ESRD patients are particularly susceptible to COVID-19 infection.

Thymalfasin (thymosin alpha 1, Ta1) is a naturally occurring peptide that has been evaluated for its immunomodulatory activities and related therapeutic potential in several conditions and diseases, including infectious disease and cancer. ZADAXIN, a synthetic form of Ta1, been has been used clinically in pilot studies for treatment of severe acute respiratory syndrome (SARS) and other lung infections including acute respiratory distress syndrome (ARDS) and chronic obstructive pulmonary disorder (COPD), as well as infections after bone marrow transplant]. Larger clinical trials have shown significant efficacy for treatment of severe sepsis and hepatitis B, along with certain cancers such as melanoma, hepatocellular, and lung cancer. Ta1 has also demonstrated improvement in response to vaccines in the elderly and in patients immunocompromised by renal disease. The beneficial clinical effects of Ta1 result from activation of toll-like receptor (TLR) 9 in dendritic and other immune system cells, resulting in augmentation of T helper (Th1) function, natural killer (NK) cell activity, and increased antibody responses to T-cell dependent antigens. Importantly, Ta1 also leads to an increase in IL-10 producing regulatory T cells, which create feedback inhibition of cytokine production, hence dampening immune response and preventing a pro-inflammatory cytokine storm.

It is our hypothesis that a course of Ta1 administered to individuals at high risk for COVID-19 infection (hemodialysis patients) will reduce the rate of COVID-19 infection and severity of infection with COVID-19, compared to untreated individuals in the same hemodialysis units with comparable risk. The study will also evaluate the need for hospitalization in those patients who do not become infected with COVID-19.

Study Type

Interventional

Enrollment (Actual)

189

Phase

  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

    • Kansas
      • Kansas City, Kansas, United States, 64111
        • Clinical Research Consultants

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

60 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Age 18 or greater
  • Signed informed consent
  • End-stage renal disease (ESRD) who receive hemodialysis 2 or more times each week and are expected to continue on dialysis indefinitely.

Exclusion Criteria:

  • Patients on short-term hemodialysis, such as those with transient renal dysfunction associated with acute illness who are projected to have return in renal function
  • Patients for whom renal transplantation is anticipated within the next six months
  • Patients with an anticipated survival of less than 3 months
  • Patients with symptoms that might be attributable to COVID-19 infection
  • Patients who test positive for SARS-CoV2
  • Patients with active infectious disease requiring antibiotics
  • Patients with hospitalization within the previous 3 months for acute myocardial infarction or congestive heart failure
  • Patients with advanced malignancy receiving cytotoxic chemotherapy
  • Patients with a Karnofsky Performance Scale score of less than 60
  • Patients with prior history of solid organ (kidney, liver, heart, lung, pancreas) or bone marrow transplant
  • Patients with active autoimmune disease on immunosuppressive medication
  • Patients receiving Plaquenil
  • Participation in an investigational drug or device trial in previous 30 days
  • History of allergy or intolerance to Ta1
  • Any other medical or psychiatric condition that, in the opinion of the Investigator, would compromise patient safety or interfere with the objectives of the protocol or completion of the protocol treatment

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Active arm
1.6 mg thymalfasin in 1 mL subcutaneous injection twice weekly after dialysis for 8 weeks
Synthetic 28 amino acid peptide
Other Names:
  • Thymosin alpha 1
  • Ta1
  • ZADAXIN
No Intervention: Control arm
Standard care

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Number of Participants With COVID-19 Infection
Time Frame: 6 months
Number of subjects who become infected with COVID-19 over the course of the study
6 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Hospitalization
Time Frame: 6 months
Number of participants who were hospitalized
6 months
Non-COVID-19 Infections
Time Frame: 6 months
Number of participants with non-COVID-19 infections
6 months
Mortality
Time Frame: 6 months
Number of subjects who died
6 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

January 12, 2021

Primary Completion (Actual)

January 19, 2023

Study Completion (Actual)

January 19, 2023

Study Registration Dates

First Submitted

June 7, 2020

First Submitted That Met QC Criteria

June 10, 2020

First Posted (Actual)

June 11, 2020

Study Record Updates

Last Update Posted (Actual)

April 21, 2026

Last Update Submitted That Met QC Criteria

April 15, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

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

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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