Long-term safety of infants from mothers with chronic hepatitis B treated with tenofovir disoproxil in China.

OBJECTIVE: The physical and neuromental development of infants remains uncertain after fetal exposure to tenofovir disoproxil fumarate (TDF) for the prevention of mother-to-child transmission of HBV. We aimed to investigate the safety of TDF therapy during the third trimester of pregnancy. DESIGN: Infants from a previous randomised controlled trial were recruited for our long-term follow-up (LTFU) study. Mothers with chronic hepatitis B were randomised to receive TDF therapy or no treatment during the third trimester. Infants' physical growth or malformation, bone mineral density (BMD) and neurodevelopment, as assessed using Bayley-III assessment, were examined at 192 weeks of age. RESULTS: Of 180 eligible infants, 176/180 (98%) were enrolled and 145/176 (82%) completed the LTFU (control group: 75; TDF-treated group: 70). In the TDF-treated group, the mean duration of fetal exposure to TDF was 8.57±0.53 weeks. Congenital malformation rates were similar between the two groups at week 192. The mean body weight of boys in the control and TDF-treated groups was significantly higher (19.84±3.46 kg vs. 18.47±2.34 kg; p=0.03) and within the normal range (18.48±2.35 kg vs. 17.80±2.50 kg; p=0.07), respectively, when compared with the national standard. Other prespecified outcomes (head circumference, height, BMD, and cognitive, motor, social-emotional, and adaptive behaviour measurements) were all comparable between the groups. CONCLUSION: Infants with fetal exposure to TDF had normal physical growth, BMD and neurodevelopment at week 192. Our findings provide evidence on the long-term safety of infants after fetal exposure to maternal TDF therapy for preventing hepatitis B transmission. TRIAL REGISTRATION NUMBER: NCT01488526.