Diese Seite wurde automatisch übersetzt und die Genauigkeit der Übersetzung wird nicht garantiert. Bitte wende dich an die englische Version für einen Quelltext.

Positron Emission Tomography and Organ-Specific Changes in Participants Co-Enrolled in NIH Studies of Plasmodium Vivax Controlled Human Malaria Infection

Background:

Malaria is a serious disease caused by parasites spread by mosquitoes. To better diagnose and treat malaria, researchers need to learn more about where the parasites go when they enter a person's body. They want to see if they can locate the malaria parasites in the body using imaging scans.

Objective:

To learn whether imaging scans can locate parasites in people with malaria.

Eligibility:

Healthy people aged 18 to 54 years. They must be enrolled in protocol IRB001970 or IRB002627 for controlled malaria infection.

Design:

Participants will be screened. They will have blood drawn and a physical exam, including an abdominal exam to check the size of their spleen.

Participants for this study will have 2 or 3 positron emission tomography/computed tomography (PET/CT) scans: The first will be about 3 days before they are deliberately infected with malaria for a different study. The second will be about 13 days later, while they have the disease. The third scan is optional; it will be done about 3 and 1/2 weeks after the second scan.

For each scan, participants will receive a radioactive tracer called fluorodeoxyglucose (FDG). FDG will be injected through a tube inserted into a vein. They will lie on a table that slides through a doughnut-shaped machine. PET/CT uses x-rays to create images of the inside of the body.

All participants will have a follow-up visit about 3 and 1/2 weeks after the second scan. The blood draw and physical exam will be repeated. This visit may be combined with the third scan for those who choose it.

Studienübersicht

Detaillierte Beschreibung

Study Description:

Participants who are enrolled in a Plasmodium vivax challenge model protocol at the NIH Clinical Center (CC) may be co-enrolled in this single-site study to undergo a 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET)/computed tomography (CT) scan of their chest, abdomen, and pelvis at baseline before controlled human malaria infection (CHMI) inoculation and again at the expected time of peak parasitemia. FDG uptake will be used to visualize organ-specific changes as a result of malaria infection. Other assessments will include inflammatory labs, signs of bone marrow activation, compete blood count (CBC), reticulocyte counts, and transcriptional analysis.

Objectives:

Primary Objectives:

-To measure changes in spleen standardized uptake value (SUV) from baseline in participants undergoing P. vivax CHMI using PET/CT imaging

Secondary Objectives:

  • Key secondary: To measure changes in organ-specific uptake of FDG from baseline in participants undergoing P. vivax CHMI using PET/CT imaging.
  • Explore the relationship between dyserythropoiesis, hematological abnormalities, and bone marrow/splenic involvement in acute P. vivax malaria.

Exploratory Objectives:

  • To better understand the biomass and sequestration of P. vivax malaria.
  • Improve understanding of timing and location of P. vivax sequestration in tissues.
  • Measure host and parasite factors that lead to organ-specific P. vivax disease.
  • Improve understanding of convalescent changes for expected or unexpected changes in organ size or SUV due to P. vivax after treatment

Endpoints:

Primary Endpoint:

-Percentage change in mean spleen SUV from baseline to post CHMI

Key Secondary Endpoints:

  • Percentage change in max spleen SUV
  • Percentage change in peak spleen SUV
  • Percentage change in spleen volume

Additional Secondary Endpoints:

  • Percentage change in liver volume
  • Percentage change in mean, max, and peak liver SUV
  • Percentage change in mean, max and peak bone marrow SUV
  • CBC with differential, reticulocyte count, and erythropoietin (EPO) at baseline, at the time of the second FDG-PET/CT, and at the end of the CHMI-related activities performed under the co-enrolled study.

Exploratory Endpoints:

  • Describe the relationship between parasitemia/gametocytemia and organ size changes and SUV on FDG-PET/CT with exploratory labs like Plasmodium vivax-specific LDH and others.
  • Other exploratory studies may include but are not limited to proteomic and metabolomic analysis, 10x genomics, and immunophenotyping using flow cytometry or immunohistochemistry (IHC) on peripheral blood mononuclear cells (PBMCs), cytokine levels.
  • Percentage change in organ volume and mean SUV after treatment compared to baseline and compared to the time of peak parasitemia

Studientyp

Interventionell

Einschreibung (Geschätzt)

45

Phase

  • Unzutreffend

Kontakte und Standorte

Dieser Abschnitt enthält die Kontaktdaten derjenigen, die die Studie durchführen, und Informationen darüber, wo diese Studie durchgeführt wird.

Studienkontakt

Studienorte

    • Maryland
      • Bethesda, Maryland, Vereinigte Staaten, 20892
        • National Institutes of Health Clinical Center
        • Kontakt:

Teilnahmekriterien

Forscher suchen nach Personen, die einer bestimmten Beschreibung entsprechen, die als Auswahlkriterien bezeichnet werden. Einige Beispiele für diese Kriterien sind der allgemeine Gesundheitszustand einer Person oder frühere Behandlungen.

Zulassungskriterien

Studienberechtigtes Alter

18 Jahre bis 54 Jahre (Erwachsene)

Akzeptiert gesunde Freiwillige

Nein

Studienberechtigte Geschlechter

Alle

Beschreibung

  • INCLUSION CRITERIA

In order to be eligible to participate in this study, an individual must meet all of the following criteria:

  1. Aged >=18 and <=54 years.

  2. Able to provide informed consent.

  3. Co-enrolled in NIH protocol IRB001970, "Phase 1 study of induced blood-stage malaria in healthy malaria-naive adults to assess the safety and infectivity of Plasmodium vivax challenge agent and evaluate transmission in mosquito feeding assays" or IRB002627, "Phase 1/2 study of transmission-blocking vaccine Pvs230D1-EPA/Matrix-M in healthy malaria-naive adults using a Plasmodium vivax controlled human malaria infection model."

  4. Willing to allow long-term storage of study samples for future research.

  5. Individuals of childbearing potential must agree to use an acceptable method of contraception from 1 month prior to the first FDG-PET/CT scan through the end of the study. Participants will also be expected to adhere to the strictest of the contraception

    requirements of any studies they are co-enrolled in. Acceptable methods of contraception include the following:

    • A barrier method (e.g., consistent condom use) combined with an oral contraceptive pill, hormonal patch, or ring.
    • Parenteral hormonal contraceptive implant or an intrauterine device.

    Participants who otherwise are not at risk of becoming pregnant, at the judgement of the investigator will not be required to use contraception. Such participants may include those:

    • Having undergone hysterectomy, bilateral oophorectomy, or bilateral fallopian tube ligation.
    • Having reached menopause (age >=45 years plus no menses for 12 consecutive months without an alternative medical cause).
    • Having exclusive same-sex relations or committed longstanding abstinence due to a serious life choice.
    • Having an exclusive male partner who has undergone vasectomy at least 4 months prior.
  6. Participants need to have established medical care with a primary care doctor or be willing to establish care in case medically relevant findings on their imaging require follow-up.

EXCLUSION CRITERIA

An individual who meets any of the following criteria will be excluded from participation in this study:

  1. Pregnancy or lactation.
  2. History of splenectomy.
  3. History of diabetes or poorly controlled blood sugar, in the judgement of the investigators, would prevent completion of FDG-PET/CT scan.
  4. Currently undergoing therapy with drugs that, in the judgment of the investigators, may interfere with biodistribution of FDG (e.g., insulin that cannot be held or metformin that cannot be stopped for 48 hours prior to each FDG-PET/CT.).
  5. Any other finding that, in the judgment of the investigator, would interfere with, or serve as a contraindication to, protocol adherence, assessment of safety, or a participant s ability to give informed consent, or increase the risk of having an adverse outcome from

participating in the study.

Co-enrollment guidelines: Co-enrollment in other trials is restricted, other than enrollment on the LMIV CHMI trials described above and NIH protocol 17I0122, NIAID Centralized Sequencing Protocol. Study staff should be notified of co-enrollment on any other protocol as it may require the approval of the principal investigator.

Studienplan

Dieser Abschnitt enthält Einzelheiten zum Studienplan, einschließlich des Studiendesigns und der Messung der Studieninhalte.

Wie ist die Studie aufgebaut?

Designdetails

  • Hauptzweck: Grundlegende Wissenschaft
  • Zuteilung: N / A
  • Interventionsmodell: Einzelgruppenzuweisung
  • Maskierung: Keine (Offenes Etikett)

Waffen und Interventionen

Teilnehmergruppe / Arm
Intervention / Behandlung
Experimental: Healthy Volunteers who are co-enrolled in a P. vivax CHMI study

Healthy Volunteers are co-enrolled in a Plasmodium vivax challenge model protocol at the NIH Clinical Center.

Participants are co-enrolled in a Plasmodium vivax challenge model protocol at the NIH Clinical Center. These participants will undergo up to 3 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET)/computed tomography (CT) scans of their chest, abdomen, and pelvis. PET/CT scans will occur at baseline (before controlled human malaria infection (CHMI) inoculation), and at the expected time of peak parasitemia. Participants may have an optional 3rd PET/CT scan at day 34 after the CHMI inoculation. FDG uptake will be used to visualize organ-specific changes as a result of malaria infection.

Was misst die Studie?

Primäre Ergebnismessungen

Ergebnis Maßnahme
Maßnahmenbeschreibung
Zeitfenster
To measure changes in spleen standardized uptake value (SUV) from baseline in participants undergoing P. vivax CHMI using PET/CT imaging
Zeitfenster: 34 (+/- 5 days) days post CHMI Inoculation

Percentage change in mean spleen SUV from baseline to post-CHMI

34 (+/- 5 days) days post CHMI Inoculation

Sekundäre Ergebnismessungen

Ergebnis Maßnahme
Maßnahmenbeschreibung
Zeitfenster
To measure changes in organ specific uptake of FDG from baseline in participants undergoing P. vivax CHMI using PET/CT imaging
Zeitfenster: 34 (+/- 5 days) days post CHMI Inoculation

Percentage change in max spleen SUV Percentage change in peak spleen SUVPercentage change in spleen volume Percentage change in liver volumePercentage change in liver SUVPercentage change in bone marrow SUV

34 (+/- 5 days) days post CHMI Inoculation
Explore the relationship between dyserythropoiesis, hematological abnormalities, and bone marrow/splenic involvement in acute P. vivax malaria.
Zeitfenster: 34 (+/- 5 days) days post CHMI Inoculation

CBC with differential, reticulocyte count, and erythropoietin (EPO) at baseline, at the time of the second FDG-PET/CT, and at the end of the CHMI-related activities performed under the co-enrolled study.

34 (+/- 5 days) days post CHMI Inoculation

Mitarbeiter und Ermittler

Hier finden Sie Personen und Organisationen, die an dieser Studie beteiligt sind.

Ermittler

  • Hauptermittler: Shanan R Immel, M.D., National Institute of Allergy and Infectious Diseases (NIAID)

Publikationen und hilfreiche Links

Die Bereitstellung dieser Publikationen erfolgt freiwillig durch die für die Eingabe von Informationen über die Studie verantwortliche Person. Diese können sich auf alles beziehen, was mit dem Studium zu tun hat.

Studienaufzeichnungsdaten

Diese Daten verfolgen den Fortschritt der Übermittlung von Studienaufzeichnungen und zusammenfassenden Ergebnissen an ClinicalTrials.gov. Studienaufzeichnungen und gemeldete Ergebnisse werden von der National Library of Medicine (NLM) überprüft, um sicherzustellen, dass sie bestimmten Qualitätskontrollstandards entsprechen, bevor sie auf der öffentlichen Website veröffentlicht werden.

Haupttermine studieren

Studienbeginn (Geschätzt)

8. November 2026

Primärer Abschluss (Geschätzt)

1. November 2030

Studienabschluss (Geschätzt)

1. November 2030

Studienanmeldedaten

Zuerst eingereicht

3. Oktober 2026

Zuerst eingereicht, das die QC-Kriterien erfüllt hat

5. Oktober 2026

Zuerst gepostet (Tatsächlich)

6. Oktober 2026

Studienaufzeichnungsaktualisierungen

Letztes Update gepostet (Tatsächlich)

3. November 2026

Letztes eingereichtes Update, das die QC-Kriterien erfüllt

2. November 2026

Zuletzt verifiziert

8. Oktober 2026

Mehr Informationen

Begriffe im Zusammenhang mit dieser Studie

Plan für individuelle Teilnehmerdaten (IPD)

Planen Sie, individuelle Teilnehmerdaten (IPD) zu teilen?

UNENTSCHIEDEN

Arzneimittel- und Geräteinformationen, Studienunterlagen

Studiert ein von der US-amerikanischen FDA reguliertes Arzneimittelprodukt

Nein

Studiert ein von der US-amerikanischen FDA reguliertes Geräteprodukt

Nein

Diese Informationen wurden ohne Änderungen direkt von der Website clinicaltrials.gov abgerufen. Wenn Sie Ihre Studiendaten ändern, entfernen oder aktualisieren möchten, wenden Sie sich bitte an register@clinicaltrials.gov. Sobald eine Änderung auf clinicaltrials.gov implementiert wird, wird diese automatisch auch auf unserer Website aktualisiert .

Abonnieren