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Leishmaniasis, CutaneousLEISHVACNCT07783243

Ex Vivo Immunogenicity Screening of Vaccine Candidate Antigen Combinations in Ethiopian Patients With Leishmaniasis

An observational study of Leishmaniasis, Cutaneous and Leishmaniasis, run by Institute of Tropical Medicine, Belgium at 2 sites in Ethiopia.

Recruiting

Looking for participants now. Contact the study team or a site below to ask about taking part.

Sites and contacts
Official record
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Trial summary

This study assesses the immunoprevalence (presence of the induced T-cell response across different patients (and thus HLA types) of six prioritized IPX-derived Leishmania antigens, using Good Laboratory Practice-grade soluble Leishmania antigen (GLP-SLA) as a positive control. Read more about this study

Who is it for?
Ages 18 to 65 yearsHealthy volunteers can take part
How many people
90 participants
Where
2 sitesEthiopia
Study dates
26 May 2026to Dec 2026
How long will I take part?
90 Days
Phase
Observational
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 65 years
  • All sexes
  • Healthy volunteers accepted
  • Adult, Older adult

Study population: Ethiopian population

Who may be able to join

  • Aged 18-65 years To minimize variability within this first study to verify induced T-cell responses specifically towards vaccine candidate target antigens/peptide pools, we focus on more robust adult immune responses. Children and elderly are vulnerable populations with divergent immune responses and are therefore excluded.
  • Suspected diagnosis of VL or CL, defined as:
  • VL: Clinically suspected VL presentation (e.g., prolonged fever, splenomegaly)
  • CL: Clinically suspected lesions (e.g., nodular, ulcerative, or plaque-like lesions) Including suspected VL and CL patients was done in earlier VL and CL studies (Clinicaltrials.gov Identifier: NCT05602610 and NCT05332093, >95% of suspected cohort confirmed to have VL or CL, respectively) to facilitate efficient recruitment flow for both the patient as the study team.
  • Willing and able to provide informed consent Ensures autonomy and understanding, allowing participants to fully understand their risks and benefits, and the possibility to withdraw at any time without affecting care.
  • Aged 18-65 years Matching the age range of VL and CL patients
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  • Resides in Addis Ababa An uninfected control group is included to distinguish true antigen-specific T-cell responses from non-specific (background) T-cell activation. This control group should ideally consist of healthy individuals without prior symptomatic or asymptomatic exposure to Leishmania, as previous (unknown) asymptomatic infections could lead to detectable Leishmania-specific T-cell responses and thus confound background baseline measurements. To minimize this risk, we will recruit healthy volunteers from 'non-infected' areas, specifically the Addis Ababa region, and apply strict (retrospective) exclusion criteria to ensure absence of prior Leishmania exposure.
  • Generally healthy Ensures volunteers who are not in a state of severe medical nor socioeconomic vulnerability, to ensure that participation is not unduly influenced by financial compensation.
  • Willing and able to provide informed consent. Ensures autonomy and understanding, allowing participants to fully understand their risks and benefits, and the possibility to withdraw at any time without affecting care.
  • Passed autonomy and voluntariness assessment (questions listed below) to further ensure autonomy and understanding.
  • Can you explain in your own words what participation involves and that it is voluntary?
  • Would saying no affect your access to care in any way?
  • Is the compensation offered influencing your decision in a way that makes you feel you must participate?
  • Would not receiving this compensation cause you significant difficulty?

Who cannot join

  • Are currently enrolled in another interventional clinical study
  • Have known severe comorbidities (e.g., autoimmune disease, HIV, tuberculosis, leprosy, or malaria)
  • Have known pregnancy
  • Cognitively impaired individuals
  • Have received immunosuppressive drugs in the past month
  • Have received a vaccine in the past month
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  • Have received modern antileishmanial treatment in the past month
  • Are on anticoagulation medication or have bleeding disorders that would contraindicate safe blood or tissue sampling
  • For CL patients:
  • Primary lesion size < 2 cm
  • Too difficult or too painful sampling zone (e.g., close to the mucosa or lymphatic system, on joints, eyelid or ear)
  • Not eligible for systemic SSG treatment
  • Ethiopian 'non-infected' healthy volunteers
  • Have history of contracting VL or CL
  • Cohabitate with a person treated for CL/VL within the past 12 months
  • Residence or overnight stays in any of these areas within the past 5 years should be considered potentially exposed, even if they reside in the capital.
  • Kebeles in Addis: Saris, Kality, and Akaki
  • Ethiopian highlands: widespread foci for CL in Amhara (South Gondar, North Gondar, South Wollo, North Wollo), Tigray (Wukro, Mekelle surroundings), Oromia (Sebeta, Bale, Jimma), and SNNPR (Silte, Gurage, Sidama highlands).
  • VL endemic lowland/hotspot areas: Afar, Somali Region, Benishangul-Gumuz, Metema-Humera lowlands (Amhara/Tigray border), and South Omo (SNNPR).
  • Have known severe comorbidities (e.g., autoimmune disease, HIV, tuberculosis, leprosy, and malaria)
  • Have known pregnancy
  • Cognitively impaired individuals
  • Have received immunosuppressive drugs in the past month
  • Have received a vaccine in the past month
  • Are on anticoagulation medication or have bleeding disorders that would contraindicate safe blood or tissue sampling
  • If their Leish-IGRA demonstrate positive values, the participant will be retrospectively excluded as this indicates the presence of a past Leishmania infection.

Trial locations and contacts

2 sites in 1 country. Contact the study team or a site near you to ask about taking part.

Thao-Thy Pham, PhD contact

+32(0)33455227

thaothypham@itg.be

Ethiopia2 sites, 2 recruiting
  • Armauer Hansen Research Institute

    Addis Ababa

    Eshetu Molla, PhD, +251(0)9 12 35 62 50, eshetmolla@gmail.com

    Shimelis Doni, MD, +251(0)9 11 64 20 60, shimelis321@gmail.com

    Recruiting
  • Leishmaniasis Research and Treatment Center

    Gonder

    Mezgebu Asres, MD, +251921576259, mezgebusilamsaw@yahoo.com

    Recruiting

Other trials in Ethiopia

About this study

Official title: Ex Vivo Immunogenicity Screening of Vaccine Candidate Antigen Combinations in Ethiopian Patients With Visceral and Cutaneous Leishmaniasis

This study assesses the immunoprevalence (presence of the induced T-cell response across different patients (and thus HLA types) of six prioritized IPX-derived Leishmania antigens, using Good Laboratory Practice-grade soluble Leishmania antigen (GLP-SLA) as a positive control. Longitudinal GLP-SLA stimulation validates its IFN-γ release assay performance to support licensing of a QuantiFERON-like test (Leish-IGRA) for treatment monitoring. IPX-derived Leishmania antigen screening focuses on day 0 and EOT, while GLP-SLA includes all timepoints. Induced T-cell responses by ex vivo stimulation of blood and tissue samples (lesion, bone marrow, or spleen) from patients with cutaneous and visceral leishmaniasis (two-centre cohort) before and after treatment will be verified. Samples from Ethiopian 'non-infected' healthy volunteers will be included in parallel to differentiate from Leishmania antigen-specific versus aspecific T-cell activation. The induced T-cell response will mainly be determined by the expressed IFN-γ levels after stimulation. Additional analyses are included to further characterize the activation and cytokine profiles of these IPX-derived Leishmania antigen-specific T-cells, while the breadth of the T-cell response will be determined by mapping the response across different patients (and thus different HLA types).

Read the detailed description

Despite decades of effort, to date, there is no licensed vaccine for human leishmaniasis. For subunit vaccine development, candidate antigens were mostly identified through in silico predictions or animal experimental models, and their immunogenicity, while promising in these systems, did not translate into sufficiently or consistently induced T-cell responses in humans.

To address this gap, the Institute of Tropical Medicine Antwerp (ITM) has recently applied a sensitive immunopeptidomics method (IPX) to directly identify naturally processed and MHC-presented Leishmania epitopes from tissue samples of patients with cutaneous leishmaniasis (CL). These epitopes, and their source antigens, represent clinically relevant human-derived vaccine candidate targets.

This study assesses the immunoprevalence (presence of the induced T-cell response across different patients (and thus HLA types) of six prioritized IPX-derived Leishmania antigens, using Good Laboratory Practice-grade soluble Leishmania antigen (GLP-SLA) as a positive control. Longitudinal GLP-SLA stimulation validates its IFN-γ release assay performance to support licensing of a QuantiFERON-like test (Leish-IGRA) for treatment monitoring. IPX-derived Leishmania antigen screening focuses on day 0 and EOT, while GLP-SLA includes all timepoints. Induced T-cell responses by ex vivo stimulation of blood and tissue samples (lesion, bone marrow, or spleen) from patients with cutaneous and visceral leishmaniasis (two-centre cohort) before and after treatment will be verified. Samples from Ethiopian 'non-infected' healthy volunteers will be included in parallel to differentiate from Leishmania antigen-specific versus aspecific T-cell activation. The induced T-cell response will mainly be determined by the expressed IFN-γ levels after stimulation. Additional analyses are included to further characterize the activation and cytokine profiles of these IPX-derived Leishmania antigen-specific T-cells, while the breadth of the T-cell response will be determined by mapping the response across different patients (and thus different HLA types).

Keywords
leishmania vaccine candidate antigens, leishmania vaccine, leishmaniasis vaccine
Medical subject headings
Leishmaniasis, Cutaneous, Leishmaniasis, Leishmaniasis, Visceral

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

Study groups in NCT07783243
Study groupRoleWhat they receive
Ethiopian non-infected healthy volunteersNot described
cutaneous leishmaniasisNot described
visceral leishmaniasisNot described

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. To determine the immunoprevalence of IPX-derived Leishmania antigens and their combinations in Ethiopian patients with VL and CL.

    Proportion of patients that demonstrate an induced T-cell response (represented by IFN-γ expression) after ex vivo stimulation of IPX-derived antigens Leishmania and combinations.

    Measured: "Day 0" (baseline) until "Day 17" or "Day 28" (end of treatment, may vary due to treatment)

Secondary outcomes (5)
  1. To further characterize the phenotype (e.g., flow cytometry, single-cell sequencing) and polyfunctionality (multiplex cytokine determination) of the induced T-cell response after ex vivo stimulation with IPX-derived Leishmania antigens and GLP-SLA

    Measured: "Day 0" (baseline) until "Day 17" or "Day 28" (end of treatment, may vary due to treatment)

  2. To compare the induced T-cell response of IPX-derived Leishmania antigens with GLP-SLA in blood versus tissues, by clinical presentation

    Measured: "Day 0" (baseline) until "Day 17" or "Day 28" (end of treatment, may vary due to treatment)

  3. To determine the dynamics of the induced T-cell response of IPX-derived Leishmania antigens versus GLP-SLA before and at end of successful versus failed treatment

    Measured: "Day 0" (baseline) until "Day 17" or "Day 28" (end of treatment, may vary due to treatment)

  4. To assess the predictive value of the Leish-IGRA for treatment outcome in CL and VL patients before, during and at end of treatment

    Measured: "Day 0" (baseline), "Day 7", until "Day 17" or "Day 28" (end of treatment, may vary due to treatment)

  5. To characterize the HLA-TCR interactions involved in the recognition of IPX-derived Leishmania antigens through TCR sequencing and HLA typing

    Measured: "Day 0" (baseline) until "Day 17" or "Day 28" (end of treatment, may vary due to treatment)

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted24 Aug 2026
  2. Study start26 May 2026
  3. Primary completionDec 2026 (estimated)
  4. Study completionDec 2026 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Observational
Observational model
Cohort
Time perspective
Prospective
Enrolment
90 participants (estimated)
Target duration
90 Days
IDs, dates and publications
ClinicalTrials.gov ID
NCT07783243
Sponsor's protocol ID
1950/25
Acronym
LEISHVAC
Status last verified
Aug 2026
First submitted
15 May 2026
Last updated
24 Aug 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
Yes: IPD can be requested via the Data Access Committee of the Institute of Tropical Medicine Antwerp (https:// www. itg. be/ en/ resea rch/ data-shari ng-and-open-access) via a formal application and signed Data Sharing Agreement. In line with the study's data sharing policy, these datasets will be made available one year after completion of all planned primary publications.

Questions about this trial

What is this clinical trial studying?

An observational study of Leishmaniasis, Cutaneous and Leishmaniasis, run by Institute of Tropical Medicine, Belgium at 2 sites in Ethiopia.

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 14 inclusion and 26 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 24 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 2 sites in Ethiopia. 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.

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 Eshetu Molla, PhD (00251 9 12 35 62 50, eshetmolla@gmail.com), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

To determine the immunoprevalence of IPX-derived Leishmania antigens and their combinations in Ethiopian patients with VL and CL. (time frame: "Day 0" (baseline) until "Day 17" or "Day 28" (end of treatment, may vary due to treatment)). 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 24 Aug 2026.

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