CROI 2017 Abstract e-Book

Abstract eBook

Poster and Themed Discussion Abstracts

Conclusion: Besides receipt of antenatal PI-based ART, a number of obstetrical risk factors contributed to LBW and PTD for HIV-infected pregnant women in PROMISE. Along with optimization of ART regimens, public health interventions are needed to address modifiable obstetrical risk factors, including education of pregnant women and clinicians on early warning signs and management of pregnancy-associated complications. 778 DO HIV+WOMEN ON PROTEASE INHIBITORS DELIVER PRETERM? FINDINGS FROM A UK STUDY Graziella Favarato , Claire Townsend, Heather Bailey, Claire Thorne, for the UK and Ireland National Study of HIV in Pregnancy and Childhood (NSHPC) Univ Coll London, London, UK Background: HIV-infected women on ritonavir-boosted protease inhibitor (PI/r) based ART regimens in pregnancy may be at higher risk of preterm delivery (PTD, <37weeks gestation) but evidence is inconsistent. Methods: We analyzed national surveillance data on HIV-infected women delivering a live-born singleton in the UK and Ireland between 2007 and 2015, who received antenatal ART. We excluded women who switched ART regimen in pregnancy; for women with repeat pregnancies we retained the most recent one. We compared PTD risk in pregnant women on NNRTI+2NRTI regimens, LPV/r+2NRTI regimens and other-PI/r+2NRTI regimens using multivariable logistic regression models. Analyses were adjusted for calendar year, maternal age, intravenous drug use (IDU) history, ART at conception and first antenatal CD4 count. After excluding women with a history of IDU we explored whether the association between regimen in pregnancy and PTD was modified by first antenatal CD4 count and consequently, stratified analyses by CD4 count (≤350cells/µl vs >350cells/µl). Results: Analyses included 1889 pregnant women on NNRTI+2NRTI, 2368 on LPV/r+2NRTI and 1816 on other PI/r+2NRTI; 10.4% and 3.8% of women delivered at <37weeks and <34weeks respectively. Overall, 3090 (50.9%) women conceived on ART; 105 (1.7%) women had an IDU history. Compared to women on NNRTI regimens women on LPV/r containing regimens were at higher risk of PTD (aOR 1.48, 95%CI 1.16, 1.88) but not those on other PI/r-based regimens (aOR 1.13 95%CI 0.89, 1.43). Increased PTD risk was also associated with first antenatal CD4≤350cells/µL (aOR 1.25 95%CI 1.03, 1.50), IDU history (aOR 1.80 95%CI 1.06, 3.07) and older age (>36years vs <28years) (aOR 1.30 95%CI 1.00, 1.67). After stratifying by first antenatal CD4 count (P interaction=0.0048), increased PTD risk in women on LPV/r compared to women on NNRTI was observed in those with CD4>350cells/µL but not in those with a lower CD4 count (see Table). In women with CD4≤350cells/µl conception on ART increased PTD risk whilst risk decreased with calendar year; no increased PTD risk in women on LPV/r (or other PI/r-based regimens) compared to women on NNRTI was observed. Conclusion: In this national UK study pregnant women on LPV/r-based regimens but not on other PI/r-based regimens were at higher risk of PTD compared to pregnant women on NNRTI-based regimens but the association was only apparent in women with a higher CD4 count.

Poster and Themed Discussion Abstracts

779 TDF/FTC IN PREGNANCY SHOWS NO INCREASE IN ADVERSE INFANT BIRTH OUTCOMES IN US COHORTS

Kathryn Rough 1 , George R. Seage 1 , Paige L. Williams 1 , Sonia Hernandez-Diaz 1 , Yanling Huo 1 , Ellen G. Chadwick 2 , Risa M. Hoffman 3 , Emily Barr 4 , David E. Shapiro 1 , Kunjal Patel 1 1 Harvard Univ, Boston, MA, USA, 2 Ann & Robert H. Lurie Children’s Hosp of Chicago, Chicago, IL, USA, 3 Univ of California Los Angeles, Los Angeles, CA, USA, 4 Children’s Hosp Colorado, Aurora, CO, USA Background: In the PROMISE (Promoting Maternal and Infant Survival Everywhere) trial, infants of women randomized to tenofovir, emtricitabine, lopinivir/ritonavir (TDF/FTC/ LPV/r) had higher risk of very premature birth, very low birth weight, and death compared to those randomized to zidovudine, lamivudine, lopinavir/ritonavir (ZDV/3TC/LPV/r). Methods: Data from two large prospective US-based cohort studies (the Surveillance Monitoring for ART Toxicities cohort and the International Maternal Pediatric Adolescent AIDS Clinical Trial Network P1025 study), were used to compare risk of adverse infant birth outcomes among women exposed to ZDV/3TC/LPV/r, TDF/FTC/LPV/r, and the more frequently used TDF/FTC with atazanavir and ritonavir (ATV/r). Exposure classification was based on first regimen used during pregnancy. We evaluated the risk of preterm birth (<37 weeks), very preterm birth (<34 weeks), low birth weight (<2,500 g), very low birth weight (<1,500 g), adverse event (preterm, low birth weight, fetal loss, or 14-day mortality) and serious adverse event (very preterm, very low birth weight, fetal loss, or 14-day mortality). Risk ratios (RR) with 95% confidence intervals (CI) were estimated using log binomial models. When number of outcomes was sufficient (preterm, low birth weight, adverse event), models were adjusted for confounding. Results: Among 4,646 enrolled infants, 128 (2.8%) had mothers who received TDF/FTC/LPV/r, 539 (11.6%) had mothers who received TDF/FTC/ATV/r, and 954 (20.5%) had mothers who received ZDV/3TC/LPV/r. The overall prevalence of adverse birth outcomes was 18.8% for preterm birth, 4.5% for very preterm birth, 17.3% for low birth weight, and 1.9% for very low birth weight. In crude and adjusted comparisons, there was no statistically significant difference between TDF/FTC/LPV/r and ZDV/3TC/LPV/r for any outcome (Table), although TDF/FTC/ATV/r appeared slightly protective for preterm birth, low birth weight, and any adverse event. Conclusion: Among pregnant women with HIV in the US, use of TDF/FTC/LPV/r was not associated with increased risk of adverse infant birth outcomes when compared to ZDV/3TC/LPV/r or TDF/FTC/ATV/r. Our findings support the use of TDF/FTC/ATV/r during pregnancy, as it appears to carry similar or slightly less risk of preterm birth, low birth weight, and adverse events than ZDV/3TC/LPV/r.

CROI 2017 337