Is ((2-(6-Amino-9H-purin-9-yl)ethoxy)methyl)phosphonic acid Safe in Breastfeeding

I am a breastfeeding mother and i want to know if it is safe to use ((2-(6-Amino-9H-purin-9-yl)ethoxy)methyl)phosphonic acid? Is ((2-(6-Amino-9H-purin-9-yl)ethoxy)methyl)phosphonic acid safe for nursing mother and child? Does ((2-(6-Amino-9H-purin-9-yl)ethoxy)methyl)phosphonic acid extracts into breast milk? Does ((2-(6-Amino-9H-purin-9-yl)ethoxy)methyl)phosphonic acid has any long term or short term side effects on infants? Can ((2-(6-Amino-9H-purin-9-yl)ethoxy)methyl)phosphonic acid influence milk supply or can ((2-(6-Amino-9H-purin-9-yl)ethoxy)methyl)phosphonic acid decrease milk supply in lactating mothers?

((2-(6-Amino-9H-purin-9-yl)ethoxy)methyl)phosphonic acid has not been studied in nursing mothers being treated for hepatitis B infection. An alternate drug may be preferred, especially while nursing a newborn or preterm infant. No differences exist in infection rates between breastfed and formula-fed infants born to hepatitis B-infected women, as long as the infant receives hepatitis B immune globulin and hepatitis B vaccine at birth. Mothers with hepatitis B are encouraged to breastfeed their infants after their infants receive these preventative measures.[1][2]