Thymosin-α1 for Recurrent Implantation Failure (Thy-α1 for RIF)

June 29, 2026 updated by: Lamiya Mohiyiddeen, Fakih IVF Fertility Center

Thymosin-α1 for Recurrent Implantation Failure Following Transfer of PGT-a Tested Embryo: A Randomized, Double-Blind, Placebo-Controlled Trial

Clinical trial evaluating the safety and efficacy of Thymosin-α1 (Tα1) as an adjunctive immunomodulatory therapy in women with unexplained recurrent implantation failure (RIF) undergoing IVF/ICSI cycles.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

Despite significant advancements in assisted reproductive technologies (ART), recurrent implantation failure (RIF) remains a persistent challenge. Growing evidence implicates dysregulation of both local endometrial and systemic immune components in the pathophysiology of RIF.

This has led to increasing attention on immune dysregulation, including aberrant cytokine signaling, altered Th1/Th2 balance, heightened NK cell cytotoxicity, and impaired maternal-fetal tolerance as possible contributors. These immunological pathways are critical for embryo implantation and pregnancy continuation; their disruption can create an environment hostile to the developing conceptus.

Thymosin-α1 (Tα1) is a naturally occurring thymic peptide with immune-modulatory properties. It has been historically used in the management of chronic viral infections and certain cancers, where it demonstrated the ability to enhance T-cell function, rebalance cytokine networks, and improve immune resilience. Its safety profile in non-obstetric conditions is well established.

Although comprehensive safety evaluation of thymosin alpha in pregnant women has not yet been completed, emerging evidence from observational studies, case reports, and proposed clinical trials suggests that thymosin alpha is generally regarded as safe during pregnancy, with no reported adverse effects linked to its use to date. Specifically, a published case report documented successful pregnancy following thymosin alpha administration in a woman with recurrent implantation failure, noting an absence of fetal anomalies or significant adverse events and emphasizing the need for further prospective trials to establish broader safety and efficacy. Preliminary clinical protocols continue to monitor for adverse events in patients undergoing reproductive treatments, and none have identified safety concerns thus far.

Emerging reproductive data suggest a potential role of Tα1 in implantation and pregnancy maintenance. Observational work reported lower maternal Tα1 levels in women whose pregnancies ended in miscarriage compared with those that continued to viability; this effect was not seen with thymosin-β4, suggesting specificity. Mechanistically, Tα1 enhances T-cell maturation, restores Th1/Th2 balance, and promotes regulatory T-cell activity-processes central to maternal immune tolerance during early pregnancy.

Taken together, these findings highlight a gap: Tα1 has biological plausibility and early signals but no definitive RCT evidence. This underlines the need for a rigorous, placebo-controlled study of Tα1 in women with RIF. To our knowledge, this is the first randomized placebo-controlled study looking at Tα1 in RIF patients undergoing treatment using PGT-a tested embryos.

Study Type

Interventional

Enrollment (Estimated)

136

Phase

  • Phase 2
  • Phase 3

Contacts and Locations

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

Study Contact

Study Contact Backup

Study Locations

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

  • Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. -Women 18-40 years
  2. -RIF- ≥2 failed embryo transfers with PGT-a tested euploid embryos
  3. - Normal parental karyotypes
  4. - Normal uterine cavity on imaging
  5. - Negative antiphospholipid panel
  6. - Thyroid and prolactin controlled within local reference standards

Exclusion Criteria:

  1. Identified/correctable non-immune cause of RPL (chromosomal, anatomic, endocrine)
  2. - Active malignancy
  3. -Active infection
  4. - Uncontrolled systemic disease
  5. - Current systemic immunosuppression

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: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Placebo Comparator: Placebo
Placebo arm.
Other: Placebo Control
Matching placebo injections on the same schedule and duration.
Experimental: thymosin-α1
Thymosin α1 in recurrent implantation failure patients
Drug: Thymosin Alpha1
Start at luteal start in ART cycles and continue until 10+6 weeks' gestation.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Live birth more than 24 weeks
Time Frame: Approximately 40 weeks
From date of randomization (luteal start ART) until end of intervention at 10 + 6 weeks and assessed up to live birth or miscarriage. Approximately 40 weeks.
Approximately 40 weeks
Determine whether Tα1 increases live birth versus placebo.
Time Frame: Approximately 40 weeks
Live birth (singleton or multiple)
Approximately 40 weeks

Collaborators and Investigators

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

Sponsor

Fakih IVF Fertility Center

Investigators

  • Principal Investigator: Michael Fakih, MD, Fakih IVF Abu Dhabi

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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)

February 11, 2026

Primary Completion (Estimated)

February 1, 2027

Study Completion (Estimated)

June 1, 2027

Study Registration Dates

First Submitted

June 9, 2026

First Submitted That Met QC Criteria

June 29, 2026

First Posted (Actual)

June 30, 2026

Study Record Updates

Last Update Posted (Actual)

June 30, 2026

Last Update Submitted That Met QC Criteria

June 29, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • FAKIH-2025-13
  • DOH/ADHRTC/2026/345 (Other Identifier: Department of Health Abu Dhabi)

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

No

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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