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Completed

NCT Number: NCT05705427

The COMBAT HBV Feasibility Trial

This is a double-blind, randomized placebo-controlled trial (RCT) of a prophylaxis-for-all approach to prevention of mother-to-child transmission (PMTCT) of hepatitis B virus (HBV) in the Democratic Republic of Congo (DRC). HBV-infected pregnant women will be randomized to either receive tenofovir or placebo beginning at 28-32 weeks' gestation and continuing through 4 weeks' postpartum. Women will be followed every 4-6 weeks throughout the prenatal and postpartum period to evaluate for side effects related to the medication. Infants will receive a birth-dose of HBV vaccine, ideally within 24 hours. Participants will be followed longitudinally through 6 months' postpartum.

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Key information

Conditions

Hepatitis B Blood-Borne Infections Communicable Diseases DNA Virus Infections Digestive System Diseases Hepadnaviridae Infections Hepatitis Hepatitis, Viral, Human Infections Liver Diseases Vertical Transmission of Infectious Disease Virus Diseases

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 4

Primary location

Université Protestant au Congo

Kinshasa, Democratic Republic of the Congo

About this study

The overall study design is a randomized, double-blind, placebo-controlled trial among two groups of mother-infant dyads: women who receive TDF vs placebo in late pregnancy and the postpartum period (beginning at 28-32 weeks' gestation and continuing through 4 weeks' postpartum). While official World Health Organization (WHO) recommendations are to continue TDF at least through delivery, a range from delivery through 12 weeks' postpartum is possible; the investigators will continue therapy through 4 weeks' postpartum in this study. This feasibility trial will evaluate the acceptability, safety and preliminary effectiveness of a TDF-for-all approach to prevent MTCT of HBV in low-resource settings. HBsAg-positive pregnant women will be enrolled at 28-32 weeks' gestation, and will present for regular medication checks, with a study closeout visit at 24 weeks' postpartum. Study activities at monthly medication checks will include medication refills, assessment of adherence (via pill counts and verbal surveys), and evaluation for side effects. All infants will receive a birth-dose of HBV vaccine within 24 hours of life. MTCT of HBV will be defined as the proportion of infants with positive HBsAg testing at 6 months. This pilot study will provide preliminary data for sample size calculations, including safety and effectiveness data, to prepare for larger RCTs to determine the effectiveness of a tenofovir-for-all approach, as well as the added benefit of tenofovir over birth-dose vaccination.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Pregnant women ≥18 years of age who present for routine prenatal care between 28-32 weeks' gestation and who test HBV-positive by point-of-care hepatitis B surface antigen test. Women must intend to seek maternity and postpartum care exclusively at one of the Kinshasa-based study maternity centers.
  • Infants born to enrolled women will be included in the study

Exclusion criteria

  • Individuals with abnormal creatinine by point-of-care testing
  • Any woman who plans to move outside of Kinshasa Province during the study period.
  • Any HIV-positive individual, determined by routine point-of-care screening at antenatal care visits

Treatment and study plan

Tenofovir Disoproxil Fumarate 300 MG

Drug

Pregnant women in the experimental arm will receive TDF daily beginning in the 3rd trimester of pregnancy and continuing through 1 month postpartum.

Other names: Viread

Hepatitis B monovalent vaccine

Biological

All infants born to women in the study will receive a birth-dose hepatitis B vaccine.

Other names: Hepatitis B birth-dose vaccine, Engerix-B

Placebo

Drug

Pregnant women in the placebo arm will receive a placebo pill daily beginning in the 3rd trimester of pregnancy and continuing through 1 month postpartum.

Primary outcomes

  1. Safety (Pregnant Women): Number of Pregnant Women With Adverse Effects Related to Study Medications

    Time frame: Up to study close-out visit, or up to 12 months

    Safety of TDF prophylaxis in pregnant women, defined as a composite of adverse events (# mild adverse events [AEs], # moderate-to-severe AEs), presence of side effects and alanine aminotransferase elevations ≥ 5x upper limit of normal

  2. Safety (Infants): Number of Infants with Adverse Effects Related to Study Medications

    Time frame: At delivery

    Safety of maternal TDF for infants, defined as a composite of: Birth weight (grams), mid-upper arm circumference (centimeters), gestational age at delivery (weeks and days), delivery mode (vaginal vs C-section), APGAR scores (0-10), # of adverse events

  3. Feasibility (Recruitment): Number of Eligible Participants Who Were Enrolled in the Study

    Time frame: Up to study close-out visit, or up to 12 months

    Recruitment is indicative of the number of pregnant women who are screened versus those actually enrolled in the study.

  4. Feasibility (Refusal): Number of Eligible Participants Who Refused to Enroll in the Study

    Time frame: Up to study close-out visit, or up to 12 months

    Refusal will be defined as the number of individuals who refuse enrollment upon initial recruitment.

  5. Feasibility (Withdrawal): Number of Enrolled Participants Who Withdraw from the Study

    Time frame: Up to study close-out visit, or up to 12 months

    Withdrawal is indicative of the number of enrolled participants who choose not to continue study activities after having been enrolled.

  6. Feasibility (Retention): Number of Enrolled Participants Who Remain in the Study Through 6 Months Postpartum

    Time frame: Up to study close-out visit, or up to 12 months

    Retention is defined as the number of participants who remain in the study through the 6-month postpartum visit.

  7. Feasibility (Maintenance): Proportion of Study Visits Completed Per Participant

    Time frame: Up to study close-out visit (12 months)

    Adherence to study visits and procedures, defined as proportion of the actual number of visits attended divided by the expected study visits (8) and multiplied by 100.

  8. Acceptability (Lab Testing): Number of Mothers With Lab Testing Acceptability Scores >80%

    Time frame: Upon study close-out visit, or up to 12 months

    Number of mothers who report the process of undergoing lab draws as "acceptable" in the exit survey. Range 0-100%, with 0% being unacceptable and 100% being acceptable.

  9. Acceptability (Medication): Number of Mothers With Medication Acceptability Scores >80%

    Time frame: Upon study close-out visit, or up to 12 months

    Number of mothers who report the process of taking the study medication as "acceptable" in the exit survey. Range 0-100%, with 0% being unacceptable and 100% being acceptable.

  10. Preliminary Effectiveness: Number of Infants With HBV Positivity by Rapid Diagnostic Testing at 6 Months of Life to Indicate Mother-to-Child Transmission of HBV

    Time frame: Measured at 6 months after birth

    Mother-to-child transmission of HBV is defined as HBsAg positivity in the infant at 6 months of life.

Secondary outcomes

  1. Sensitivity of the Hepatitis B Core-Related Antigen Test

    Time frame: Measured at Enrollment

    Sensitivity will be defined as the number of true positive tests divided by the sum of the true positives and false negatives.

  2. Specificity of the Hepatitis B Core-Related Antigen Test

    Time frame: Measured at Enrollment

    Specificity will be defined as the number of true negative tests divided by the sum of the true negatives and the false positives.

Sponsors and collaborators

Lead sponsor

University of North Carolina, Chapel Hill

Other

Collaborators

  • Abbott
  • Albert Einstein College of Medicine
  • Doris Duke Charitable Foundation
  • Université Protestant au Congo

Registry information

Official study title

Simplifying Hepatitis B Care in Pregnancy by Combining Birth-dose Vaccine and Tenofovir: The COMBAT HBV Feasibility Trial

Acronym: COMBAT-HBV

Important dates

Study start
2023
Primary completion
2025
Study completion
2025
First posted
Jan 30, 2023
Registry last updated
Feb 19, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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