HIV, Pregnancy, and Isoniazid Preventive Therapy

Evidence for Implementation: Management of TB in HIV and Pregnancy

PURPOSE OF REVIEW

Pregnant people living with HIV (PLWH) are at especially high risk for progression from latent tuberculosis infection (LTBI) to active tuberculosis (TB) disease. Among pregnant PLWH, concurrent TB increases the risk of complications such as preeclampsia, intrauterine fetal-growth restriction, low birth weight, preterm-delivery, perinatal transmission of HIV, and admission to the neonatal intensive care unit. The grave impact of superimposed TB disease on maternal morbidity and mortality among PLWH necessitates clear guidelines for concomitant therapy and an understanding of the pharmacokinetics (PK) and potential drug-drug interactions (DDIs) between antitubercular (anti-TB) agents and antiretroviral therapy (ART) in pregnancy.

RECENT FINDINGS

This review discusses the currently available evidence on the use of anti-TB agents in pregnant PLWH on ART. Pharmacokinetic and safety studies of anti-TB agents during pregnancy and postpartum are limited, and available data on second-line and newer anti-TB agents used in pregnancy suggest that several research gaps exist. DDIs between ART and anti-TB agents can decrease plasma concentration of ART, with the potential for perinatal transmission of HIV. Current recommendations for the treatment of LTBI, drug-susceptible TB, and multidrug-resistant TB (MDR-TB) are derived from observational studies and case reports in pregnant PLWH. While the use of isoniazid, rifamycins, and ethambutol in pregnancy and their DDIs with various ARTs are well-characterized, there is limited data on the use of pyrazinamide and several new and second-line antitubercular drugs in pregnant PLWH. Further research into treatment outcomes, PK, and safety data for anti-TB agent use during pregnancy and postpartum is urgently needed.

Stages of pregnancy and HIV affect diagnosis of tuberculosis infection and Mycobacterium tuberculosis (MTB)-induced immune response: Findings from PRACHITi, a cohort study in Pune, India

BACKGROUND

Accurate tuberculosis infection (TBI) tests are critical for pregnant women, especially those with HIV, who have a high risk of TB disease.

METHODS

We enrolled interferon gamma release assay (IGRA)+ pregnant women with and without HIV in a longitudinal study, followed up at delivery and 6 months postpartum. Tuberculin skin test (TST) and IGRA were compared by HIV status at each timepoint.

RESULTS

Of 165 enrolled IGRA+ pregnant women: 35 (21%) had HIV and were on antiretroviral therapy with median CD4 of 476 (IQR 399-586). Compared to antepartum, significantly fewer women remained IGRA+ at delivery [HIV+ n=21/35 (62%, p=0.009); HIV- n=100/130 (77%, p=0.002)] and postpartum [HIV+ n=30/35 (87%, p=0.03); HIV- n=116/130 (89%, p=0.01)]. IGRA/TST discordance was high in pregnant women (HIV+: 51%; HIV-: 25%). Median IFN-γ was lowest for all women at delivery; significantly lower in women with HIV at all timepoints compared to women without HIV. TB incidence was 50/ 1000 person-years and 18/1000 person-years among women with and without HIV respectively.

CONCLUSIONS

Pregnancy affects TBI test results and reduces IFN-γ response to M. tuberculosis stimulation. Despite adequate CD4 counts, women with HIV express less IFN-γ than women without HIV, which may explain the high TB incidence in postpartum women with HIV.

Tuberculosis in pregnancy

Tuberculosis (TB) in pregnancy is not only a matter of the past; it is also a current problem. These days, TB appears through mass migration and tourism in countries where it was believed that this condition is eradicated. Adequate knowledge about the medical history of patients, risk factors, diagnosis and treatment of tuberculosis should be part of the armamentarium of each physician involved in clinical practice. TB is mainly found in urban and socially deprived areas. Due to the length of the treatment, there is an increased risk of drug resistance in partially treated patients. Strong knowledge about the history, risk factors, diagnosis and treatment of TB should be part of the armamentarium of each physician. Many practitioners are reluctant to request a chest X-ray in pregnancy due to the fear of harming the fetus. Bypassing a diagnosis can have a devastating effect on the mother and fetus, as well as their family and medical staff. This article discusses the matters of diagnosis and treatment of asymptomatic infection and active TB in pregnancy.

Clinical Pharmacokinetics and Pharmacodynamics of Anti-Tubercular Drugs in Pregnancy

The objectives of this qualitative review were to critically evaluate and summarize the currently available data on the use of anti-tuberculosis (TB) drugs during pregnancy, with a focus on treatment outcomes, safety, and pharmacokinetics. This qualitative, narrative review was based on literature searches in Medline, Pubmed, Embase, and Google Scholar (from their inception to 13 August 2020). Our search identified 22 papers related to treatment outcomes and 14 papers related to pharmacokinetic exposures and fetal distributions. While it is challenging to study this patient population, current evidence supports treatment of drug-susceptible TB, multidrug-resistant TB and latent TB infections. However, decisions regarding initiating, continuing, or discontinuing anti-tubercular medications while pregnant should be individualized and discussed with a specialist. Similarly, the pharmacokinetic data of anti-TB agents were mainly derived from small scale, observational studies many of which lacked high quality controls. Based on these data, it does not appear that pregnancy has an extensive impact on the pharmacokinetics of the majority of first-line and second-line agents, although caution (discussed in the review) should be exercised in data interpretation. Fetal drug exposure can also be significant and should be considered when selecting an anti-TB agent for longer term treatment. Overall, it is generally difficult to predict pregnancy-associated pharmacokinetic changes based only on drug's physiochemical characteristics.