Bone and Renal Health in Infants With or Without Breastmilk Exposure to Tenofovir-Based Maternal Antiretroviral Treatment in the PROMISE Randomized Trial

Background: We assessed bone and kidney outcomes in infants randomized postdelivery as mother-infant pairs within the IMPAACT PROMISE trial to maternal tenofovir disoproxil fumarate-based antiretroviral treatment (mART) or infant nevirapine prophylaxis (iNVP) to prevent breastfeeding HIV transmission.

Methods: Infants were coenrolled in the P1084s substudy on randomization day and followed through Week 74. Lumbar spine bone mineral content (LS-BMC) was assessed at entry (6-21 age days) and Week 26 by dual-energy x-ray absorptiometry. Creatinine clearance (CrCl) was calculated at entry; Weeks 10, 26, and 74. Student t tests compared mean LS-BMC and CrCl at Week 26 and mean change from entry between arms.

Results: Of 400 enrolled infants, the mean (SD; n) for entry LS-BMC was 1.68 g (0.35; n = 363) and CrCl was 64.2 mL/min/1.73 m 2 (24.6; n = 357). At Week 26, 98% of infants were breastfeeding and 96% on their assigned HIV prevention strategy. The mean (SD) Week 26 LS-BMC was 2.64 g (0.48) for mART and 2.77 g (0.44) for iNVP; mean difference (95% confidence interval [CI]) -0.13 g (-0.22 to -0.04), P = 0.007, n = 375/398 (94%). Mean absolute (-0.14 g [-0.23 to -0.06]) and percent (-10.88% [-18.53 to -3.23]) increase in LS-BMC from entry was smaller for mART than iNVP. At Week 26, the mean (SD) CrCl was 130.0 mL/min/1.73 m 2 (34.9) for mART vs. 126.1 mL/min/1.73 m 2 (30.0) for iNVP; mean difference (95% CI) 3.8 (-3.0 to 10.7), P = 0.27, n = 349/398 (88%).

Conclusion: Week 26 mean LS-BMC was lower in infants in the mART group compared with the iNVP group. However, this difference (∼0.23 g) was less than one-half SD, considered potentially clinically relevant. No infant renal safety concerns were observed.