Is VX-770 Safe in Breastfeeding

I am a breastfeeding mother and i want to know if it is safe to use VX-770? Is VX-770 safe for nursing mother and child? Does VX-770 extracts into breast milk? Does VX-770 has any long term or short term side effects on infants? Can VX-770 influence milk supply or can VX-770 decrease milk supply in lactating mothers?

Information from one maternal-infant pair with VX-770 and lumacaftor indicates that maternal VX-770 therapy produce low levels in milk. The breastfed infant had transient elevations in bilirubin and liver enzymes during maternal therapy that could not definitively be attributed to the drugs in breastmilk. Effect of small amounts of VX-770 in infants and small children is unknown. Until more data are available, monitoring of infant bilirubin and liver enzymes is recommended during breastfeeding with maternal lumacaftor and VX-770 therapy.

A woman with cystic fibrosis was treated with lumacaftor and VX-770 during pregnancy and postpartum. Her infant was fully breastfed until day 29 postpartum when elevated direct and indirect bilirubin, aspartate aminotransferase (AST), and alkaline phosphatase were found to be elevated. All values had been normal on days 1 and 14. The fraction of breastmilk the infant received was reduced to 25% and all values were normal on day 37. The fraction of breastfeeding was increased to 50% and then to 100%. On day 135, the infant's direct bilirubin was elevated during concurrent maternal levofloxacin and trimethoprim-sulfamethoxazole therapy. The fraction of breastfeeding was decreased to 75% and the direct bilirubin was normal on day 154. The authors noted that the abnormal test results could not definitively be attributed to lumacaftor and VX-770 therapy.[1]