Evaluating the Safety of Immediate Versus Deferred Isoniazid Preventive Therapy Among HIV-Infected Pregnant Women

TB disease is the most common HIV-related opportunistic infection and is a leading cause of death among HIV-infected persons in low-income settings. When TB occurs during or soon after pregnancy, it can cause complications for the mother as well as infant TB or death. Infant TB is very difficult to diagnose, and up to half of infant TB cases are caused by maternal TB. It has been shown that treatment for active TB is safe and effective during pregnancy and that IPT is safe and effective in preventing TB infection in HIV-infected adults. However, the safety of IPT in HIV-infected pregnant women is not known, especially in regard to its combination with highly active retroviral therapy (HAART). This study evaluated the safety of immediate (antepartum, or before delivery) versus deferred (postpartum, or after delivery) IPT among HIV-infected pregnant women in high TB incidence settings.

HIV-infected pregnant women were randomly assigned (1:1) to one of two arms: Arm A (immediate/antepartum INH) and Arm B (deferred/postpartum INH group). Women in both arms received oral prenatal multivitamins and pyridoxine (vitamin B6) once daily from study entry through Week 40 postpartum.

Study visits for women occurred at screening, entry, every 4 weeks until labor and delivery, at labor and delivery, and every 4 weeks after delivery until 48 weeks postpartum. Visits consisted of giving a medical history and undergoing a physical exam and blood collection; all visits through the delivery visit also included an obstetrical exam. Presence of HIV infection was documented at screening and a tuberculin skin test (TST) was administered at the delivery visit and at the Week 44 postpartum visit. Study visits for infants occurred at birth and at several time points through Week 48. These visits included a medical history, physical exam, and blood collection. Intensive pharmacokinetic (PK) samples, that is, samples taken at many different time points within a 24-hour test period, were collected from a small subset of women, one test period at antepartum and one at postpartum. Sparse PK samples, that is, samples taken at fewer time points within the test period, were collected on all women, once each at antepartum and postpartum.

Inclusion criteria

• Documented HIV-1 infection, defined as positive results from two samples collected at different time points. All samples tested must be whole blood, serum, or plasma. More information on this criterion can be found in the protocol.
• Documented HIV treatment, according to World Health Organization (WHO) guidelines, for prevention of mother-to-child transmission (PMTCT) and standard of care for HIV infection
• Pregnant females age 18 years or older
• Pregnant females between greater than or equal to 13 and less than 18 who are able and willing to provide signed informed consent under local law or pregnant females unable to consent under local law whose parents/legal guardians provide consent or "minimum age of consent according to locally applicable laws or regulations"
• Pregnancy gestational age confirmed by best available method at site to be greater than or equal to 14 weeks through less than or equal to 34 weeks (34 weeks, 6 days)
• Weight greater than or equal to 35 kg at screening
• The following laboratory values obtained within 30 days prior to study entry:

• Absolute neutrophil count (ANC) greater than or equal to 750 cells/mm^3
• Hemoglobin greater than or equal to 7.5 g/dL
• Platelet count greater than or equal to 50,000/mm^3
• Aspartate aminotransferase (AST)/serum glutamic oxaloacetic transaminase (SGOT), alkaline phosphatase (ALT)/serum glutamic pyruvic transaminase (SGPT), and total bilirubin less than or equal to 1.25 times the upper limit of normal (ULN). (Note: If participant is taking atazanavir, direct bilirubin may be used to determine eligibility.)
• Intent to remain in current geographical area of residence for the duration of the study

Exclusion criteria

• Any woman with a positive TB symptom screen per WHO guidelines, including any one or more of the following: any cough, fever, self-reported weight loss, or night sweats. Note: If a potential participant is found to be negative for TB upon further testing, the participant may be rescreened for the study.
• Any positive acid-fast bacillus (AFB) smear, Xpert, or any other rapid TB screening test or culture from any site within the past 12 weeks, or chest radiograph (x-ray) with findings suggestive of active TB, or clinician suspects active TB
• Known exposure to AFB smear-positive active TB case within past 12 weeks prior to study entry
• Reported INH exposure (more than 30 days) in the past year prior to study entry
• Receipt of any TB or atypical mycobacteria therapy for more than 30 days in the past year
• Evidence of acute hepatitis, such as jaundice, dark urine (not concentrated urine), and/or acholic stools sustained for more than 3 days within 90 days prior to entry. More information on this criterion can be found in the protocol.
• Grade 1 or higher peripheral neuropathy. More information on this criterion can be found in the protocol.
• History of acute systemic adverse reaction or allergy to INH
• Known current heavy alcohol use (more than 2 drinks per week) or alcohol exposure that, in the investigator's opinion, would compromise participation and the outcome of this study
• Presence of new AIDS-defining opportunistic infection that has been treated less than 30 days prior to study entry
• Receipt of an investigational agent or chemotherapy for active malignancy within 30 days prior to study entry
• Any clinically significant diseases (other than HIV infection) or clinically significant findings during the screening medical history or physical examination that, in the investigator's opinion, would compromise participation and the outcome of this study