Sequential group trial to determine gastrointestinal site of absorption and systemic exposure of azathioprine

Azathioprine (AZA) is used in the treatment of patients with refractory inflammatory bowel disease; however, its use is limited because of systemic toxicity associated with long-term use. Ileocecal delivery of AZA might be advantageous if local intestinal therapeutic effects could be provided with decreased systemic side effects. Decreased cecal systemic absorption would allow higher dosages of AZA to be administered. A two-phase study was performed to compare the systemic exposure of AZA and 6-mercaptopurine (6-MP) following administration of AZA into the stomach, jejunum, and cecum and to compare the systemic exposure to AZA and 6-MP following administration of three different dosages of AZA into the cecum. In phase I, six healthy male volunteers received three 50 mg sequential doses of AZA via an oral tube directly placed into the stomach, jejunum, and cecum, respectively. In phase II, six healthy male volunteers received three different dosages (50, 300, 600 mg of AZA) into the cecum. Plasma concentrations of AZA and 6-MP at various times were quantified and area under the plasma concentration-time curve (AUC) and mean residence time (MRT) were determined. No significant differences in the AUC of AZA were seen at the different sites. The AUC of 6-MP following administration of AZA into the jejunum (67.0 ± 30.1 ng × hr/ml) was higher compared to the stomach (39.9 ± 38.1 ng/hr/ml) and cecum (29.2 ± 10.9 ng × hr/ml). Jejunal absorption was 68% higher than absorption from the stomach and 129% higher than that of the cecum. Gastric absorption was 27% higher than that of the cecum. Increased dosages given into the cecum resulted in increased AUCs of AZA and 6-MP. The AUCs of AZA following 50, 300, and 600 mg dosages were 16.9 ± 7.4, 52.3 ± 67.2, and 132 ± 151 ng × hr/ml, respectively, and the AUCs of 6-MP were 22.2 ± 14.9, 63.4 ± 50.6, and 104 ± 115 ng × hr/ml, respectively. Systemic exposure to 6-MP is reduced following administration of AZA into the cecum, most likely secondary to reduced absorption of 6-MP from the colon. Higher dosages of AZA presented to the cecum do result in increased systemic absorption, but may still allow more drug to be administered with less toxicity than the same dose received orally

Emerging evidence from a systematic review of safety of pre-exposure prophylaxis for pregnant and postpartum women: where are we now and where are we heading?

IntroductionHIV incidence is high during pregnancy and breastfeeding with HIV acquisition risk more than doubling during pregnancy and the postpartum period compared to when women are not pregnant. The World Health Organization recommends offering pre-exposure prophylaxis (PrEP) to pregnant and postpartum women at substantial risk of HIV infection. However, maternal PrEP national guidelines differ and most countries with high maternal HIV incidence are not offering PrEP. We conducted a systematic review of recent research on PrEP safety in pregnancy to inform national policy and rollout.MethodsWe used a standard Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) approach to conduct a systematic review by searching for completed, ongoing, or planned PrEP in pregnancy projects or studies from clinicaltrials.gov, PubMed and NIH RePORTER from 2014 to March 2019. We performed a systematic review of studies that assess tenofovir disoproxil fumarate (TDF)-based oral PrEP safety in pregnant and breastfeeding HIV-uninfected women.Results and discussionWe identified 14 completed (n = 5) and ongoing/planned (n = 9) studies that evaluate maternal and/or infant outcomes following PrEP exposure during pregnancy or breastfeeding. None of the completed studies found differences in pregnancy or perinatal outcomes associated with PrEP exposure. Nine ongoing studies, to be completed by 2022, will provide data on >6200 additional PrEP-exposed pregnancies and assess perinatal, infant growth and bone health outcomes, expanding by sixfold the data on PrEP safety in pregnancy. Research gaps include limited data on (1) accurately measured PrEP exposure within maternal and infant populations including drug levels needed for maternal protection; (2) uncommon perinatal outcomes (e.g. congenital anomalies); (3) infant outcomes such as bone growth beyond one year following PrEP exposure; (4) outcomes in HIV-uninfected women who use PrEP during pregnancy and/or lactation.ConclusionsExpanding delivery of PrEP is an essential strategy to reduce HIV incidence in pregnancy and breastfeeding women. Early safety studies of PrEP among pregnant women without HIV infection are reassuring and ongoing/planned studies will contribute extensive new data to bolster the safety profile of PrEP use in pregnancy. However, addressing research gaps is essential to expanding PrEP delivery for women in the context of pregnancy

Emerging evidence from a systematic review of safety of pre‐exposure prophylaxis for pregnant and postpartum women: where are we now and where are we heading?

IntroductionHIV incidence is high during pregnancy and breastfeeding with HIV acquisition risk more than doubling during pregnancy and the postpartum period compared to when women are not pregnant. The World Health Organization recommends offering pre-exposure prophylaxis (PrEP) to pregnant and postpartum women at substantial risk of HIV infection. However, maternal PrEP national guidelines differ and most countries with high maternal HIV incidence are not offering PrEP. We conducted a systematic review of recent research on PrEP safety in pregnancy to inform national policy and rollout.MethodsWe used a standard Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) approach to conduct a systematic review by searching for completed, ongoing, or planned PrEP in pregnancy projects or studies from clinicaltrials.gov, PubMed and NIH RePORTER from 2014 to March 2019. We performed a systematic review of studies that assess tenofovir disoproxil fumarate (TDF)-based oral PrEP safety in pregnant and breastfeeding HIV-uninfected women.Results and discussionWe identified 14 completed (n = 5) and ongoing/planned (n = 9) studies that evaluate maternal and/or infant outcomes following PrEP exposure during pregnancy or breastfeeding. None of the completed studies found differences in pregnancy or perinatal outcomes associated with PrEP exposure. Nine ongoing studies, to be completed by 2022, will provide data on >6200 additional PrEP-exposed pregnancies and assess perinatal, infant growth and bone health outcomes, expanding by sixfold the data on PrEP safety in pregnancy. Research gaps include limited data on (1) accurately measured PrEP exposure within maternal and infant populations including drug levels needed for maternal protection; (2) uncommon perinatal outcomes (e.g. congenital anomalies); (3) infant outcomes such as bone growth beyond one year following PrEP exposure; (4) outcomes in HIV-uninfected women who use PrEP during pregnancy and/or lactation.ConclusionsExpanding delivery of PrEP is an essential strategy to reduce HIV incidence in pregnancy and breastfeeding women. Early safety studies of PrEP among pregnant women without HIV infection are reassuring and ongoing/planned studies will contribute extensive new data to bolster the safety profile of PrEP use in pregnancy. However, addressing research gaps is essential to expanding PrEP delivery for women in the context of pregnancy

Defining gaps in pre-exposure prophylaxis delivery for pregnant and post-partum women in high-burden settings using an implementation science framework

Pregnancy is a high-risk period for HIV acquisition in African women, and pregnant women who become acutely infected with HIV account for up to a third of vertical HIV transmission cases in African settings. To protect women and eliminate vertical transmission, WHO recommends offering oral pre-exposure prophylaxis (PrEP) based on tenofovir to HIV-negative pregnant and post-partum women with a substantial risk of HIV acquisition. PrEP implementation for pregnant and post-partum women lags behind implementation for other high-risk populations. Unique considerations for PrEP implementation arise during pregnancy and post partum, including the integration of provider training with clinical delivery and monitoring of PrEP exposure and outcomes within existing maternal health systems, yet scarce implementation data are available to generate evidence in this context