BOSTON — Results from the a substudy of mothers and infants enrolled in the IMPAACT PROMISE trial showed that tenofovir use by mothers was not associated with a loss of bone mineral content in infants.

A previous study reported 12% lower newborn mean bone mineral content after maternal tenofovir disoproxil fumarate (TDF) use.

“The good news is that [these results] give some reassurance that tenofovir was not having a major adverse impact on infant bones,” George Siberry, MD, MPH, with the US Office of Global AIDS Coordinator said at CROI 2016. “Tenofovir is part of first-line regimens for pregnant and nonpregnant women throughout the world so this is very good news.”


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P1084s is a nested, comparative substudy of IMPAACT PROMISE. IMPAACT PROMISE is a three-arm trial:  

  • Arm 1: zidovudine[ZDV] (+ single-dose nevirapine+ TDF/emtricitabine[FTC] tail);
  • Arm 2: ZDV/lamivudine/lopinavir-ritonavir[LPVr];
  • Arm 3: TDF/FTC/LPVr

Women with HIV and their infants in the substudy were randomly assigned to a maternal tenofovir-containing regimen or a no maternal tenofovir-containing regimen during pregnancy or breastfeeding for prevention of mother-to-child transmission.

In the study, 425 infants underwent whole-body and lumbar spine dual-energy X-ray absorptiometry (DXA) BMC measurements by age 28 days at 8 African sites. The primary objective was pairwise comparison between arms 2 and 3.

“We saw that was there was no difference in the bone mineral content between the infants whose mothers were assigned to take tenofovir during pregnancy and those whose mothers were assigned to take the other triple ARV regimen,” Dr Siberry said. “We did however see that the bone mineral content in those infants was lower in both triple ARV arms compared to the infants whose mothers were assigned to the AZT alone.”

Pairwise comparisons showed no significant differences in lumbar spine BMC between arm 2 (1.64g) and arm 3 (1.72g). Similarly, there was no significant difference between arm 2 (65.1g) and arm 3 (63.3g) for whole body BMC.

Researchers noted that results for lumbar spine BMC and whole body BMC for both groups was significant lower than arm 1. However, Dr Siberry said the benefits of triple ARV treatment for both the patient and for prevention of mother to child transmission “outweigh the concerns we see, potentially, in lower bone mineral content.”

Reference

1. Siberry G, Tierney C, Stranix-Chibanda L, et al. 36. Impact of Maternal Tenofovir Use on HIV-Exposed Newborn Bone Mineral. Presented at: CROI 2016. Feb. 22-25, 2016. Boston.