Evaluating PK, Tolerability, and Safety of Rifapentine and Isoniazid in Pregnant and Postpartum Women

A Phase I/II Trial of the Pharmacokinetics, Tolerability, and Safety of Once-Weekly Rifapentine and Isoniazid in HIV-1-infected and HIV-1-uninfected Pregnant and Postpartum Women With Latent Tuberculosis Infection

The purpose of this study was to evaluate the pharmacokinetics (PK), tolerability, and safety of once-weekly doses of rifapentine (RPT) and isoniazid (INH) in HIV-1-infected and HIV-1-uninfected pregnant and postpartum women with latent tuberculosis (TB).

TB is a major cause of illness and death in women of reproductive age. Pregnant and postpartum women with latent TB are at higher risk of developing active TB. This study evaluated the pharmacokinetics, tolerability, and safety of 12 once-weekly doses of RPT and INH in HIV-1-infected and HIV-1-uninfected pregnant and postpartum women with latent TB.

This study enrolled HIV-1-infected and HIV-1-uninfected pregnant women with latent TB and their infants into two cohorts based on gestation. Cohort 1 participants were enrolled in their second trimester (greater than or equal to 14 to less than 28 weeks), and Cohort 2 participants were enrolled in their third trimester (greater than or equal to 28 to less than or equal to 34 weeks). All participants received 12 directly observed once-weekly doses of RPT, INH, and pyridoxine (vitamin B6) at study entry and at 11 weekly follow-up visits. Study researchers would perform an interim analysis to assess the PK of RPT during the study, and a dose adjustment could have been recommended based on this analysis.

Study visits occurred at days 0-3, once a week through week 11, and once a month until 24 weeks after delivery. Visits would include physical examinations, obstetrical exams, and blood collection. Infants were followed monthly until 24 weeks after birth.

Inclusion Criteria:

• Age greater than or equal to 18 years, or minimum age of consent according to locally applicable laws or regulations at screening, verified per site standard operating procedures (SOPs); and able and willing to provide written informed consent for study at screening

• At screening, evidence by ultrasound of a viable singleton pregnancy with an estimated gestational age at enrollment of greater than or equal to 14 weeks through less than or equal to 34 weeks as per screening ultrasound (see protocol for more information)

• Had at least one of the following risk factors for TB:

  • Per participant report, the participant was a household contact (see NOTE below) of a known active pulmonary TB patient
  • Per medical records, confirmation of HIV-1 infection (see protocol for more information) and a single positive tuberculin skin test (TST) or interferon gamma release assay (IGRA) at any time in the past. If not available in medical record, perform at screening.

NOTE: A household contact was defined as a person who currently lives or lived in the same dwelling unit and shares or shared the same housekeeping arrangements and who reported exposure within the past two years to an adult index case with pulmonary TB. Shared housekeeping arrangements were defined as sleeping under the same roof as the index TB case for at least seven consecutive days during the one month prior to the index case TB diagnosis.

• Documentation of HIV-1 infection status, or confirmation of HIV-1 infection status (if unknown or undocumented). Confirmation of HIV-1 infection was defined as positive results from two samples (described in the protocol) collected at different time points. All samples tested must be whole blood, serum, or plasma. As this study was being conducted under an IND, all test methods should be FDA-approved, if available. If FDA-approved methods were not available, test methods should be verified according to Good Clinical Laboratory Practice (GCLP) and approved by the IMPAACT Laboratory Center. More information on this criterion was available in the protocol.

• If HIV-1-infected, documented current prescription of efavirenz (EFV) + 2 nucleoside reverse transcriptase inhibitor (NRTI) regimen and reported taking regimen for at least two weeks prior to enrollment (regimens containing protease, integrase, or entry inhibitors were not permitted)

• Documented laboratory values obtained within 14 days prior to enrollment:

  • Hemoglobin greater than or equal to 7.5 g/dL
  • White blood cell count greater than or equal to 1500 cells/mm^3
  • Alanine transaminase (ALT) less than 2.5 times the upper limit of normal (ULN)
  • Total bilirubin less than 1.6 times the ULN
  • Absolute neutrophil count (ANC) greater than or equal to 750 cells/mm^3
  • Platelet count greater than or equal to 100,000/mm^3

• Per participant report at screening, intent to remain in the current geographical area of residence for the duration of the study

• Per participant report at screening, able to swallow whole tablets

• Per participant report, intention to keep the pregnancy

• Per participant report, willingness to permit infant to participate in the study

Exclusion Criteria:

• Evidence of confirmed or probable active TB disease per World Health Organization (WHO) symptom screen and confirmation by Gene Xpert, shielded chest x-ray, or sputum sample
• Participant report of personal history of INH- or rifampin-resistant, multi-drug resistant (MDR), or extensively drug-resistant (XDR) TB
• Participant report of personal history of active TB in the past 2 years
• Participant report of previous treatment for latent tuberculosis infection (LTBI)
• Household contact (as defined above) with known active MDR or XDR TB disease
• Known major fetal abnormality as detected on ultrasound
• Known allergy/sensitivity or any hypersensitivity to components of study drugs or their formulation
• Known history of liver cirrhosis at any time prior to study entry
• Per participant report and/or medical records, evidence of acute clinical hepatitis, such as a combination of abdominal pain, jaundice, dark urine, and/or light stools within 90 days prior to entry
• Participant report and/or medical records of peripheral neuropathy Grade 2 or higher within 90 days prior to entry
• Current use or history of active drug or alcohol use or dependence that, in the opinion of the site investigator, would interfere with adherence to study requirements
• Participant report and/or clinical evidence of porphyria
• Any other condition that, in the opinion of the investigator of record (IoR)/designee, would preclude informed consent, make study participation unsafe, complicate interpretation of study outcome data, or otherwise interfere with achieving the study objectives, including taking the study medication
• Planned or current participation in an interventional drug study
• Current use of any prohibited or precautionary medications (see protocol for more information), including didanosine (DDI) or stavudine (D4T)