Real‐world study of tenofovir disoproxil fumarate to prevent hepatitis B transmission in mothers with high viral load

Summary Background Data on tenofovir disoproxil fumarate (TDF) therapy for preventing vertical transmission of hepatitis B virus (HBV) in the real‐world setting are limited. Aim To investigate TDF for preventing vertical transmission of HBV in real‐world practice. Methods Hepatitis B e‐antigen (HBeAg)‐positive mothers with HBV‐DNA >6 log 10 IU/mL to receive TDF between gestational weeks 24‐33 and delivery were prospectively enrolled and followed until post‐partum week 28. All infants received immunoprophylaxis. Primary endpoints were safety of TDF use and mother‐to‐child transmission rates. Secondary outcomes were maternal HBV‐DNA level suppression (<200 000 IU/mL) at delivery and HBeAg and hepatitis B surface antigen (HBsAg) serologic changes during the study. Results Among 147 mothers enrolled, 143 started TDF and 143/144 infants completed the study. At delivery, 93.7% (134/143) of the mothers achieved HBV‐DNA<200 000 IU/L. On‐treatment, alanine aminotransferase (ALT) flares were observed in 8.4% (12/143) of mothers. After TDF cessation, ALT increased in 7.7% (11/143) of the mothers and 2.8% (4/143) achieved HBeAg negativity, but none had HBsAg loss. At birth, HBsAg was detected in 13.9% (20/144) of newborns and none at post‐partum week 28. Vertical transmission rates among infants were 0.7% (1/144, intention‐to‐treat) and 0% (per‐protocol). No infants had birth defects. No serious adverse effects were reported in either mothers or infants. Breastfeeding did not increase the HBV infection rate among infants although mothers had viral rebound after TDF cessation. Conclusions TDF for highly viraemic mothers was well tolerated and reduced vertical transmission of HBV in a real‐world setting. There were no safety concerns during the postpartum 28‐week follow‐up. Registry number: Chinese Clinical Trial Registration No. ChiCTR‐OIC‐17010869