Updates were made to the Perinatal Guideline on January 22, 2013, January 29, 2013 and April 3, 2013. For an explanation of the updates, please see the correction notice.
(Last updated:7/31/2012; last reviewed:7/31/2012)
Enfuvirtide (Fuzeon, T-20) is classified as Food and Drug Administration (FDA) Pregnancy Category B.
Animal carcinogenicity studies
Enfuvirtide was neither mutagenic nor clastogenic in a series of in vitro and animal in vivo screening tests. Long-term animal carcinogenicity studies of enfuvirtide have not been conducted.
Reproduction/fertility animal studies
Reproductive toxicity has been evaluated in rats and rabbits. Enfuvirtide produced no adverse effects on fertility of male or female rats at doses up to 30 mg/kg/day administered SQ (1.6 times the maximum recommended adult human daily dose on an m2 body surface area basis).
Teratogenicity/developmental toxicity animal studies
Studies in rats and rabbits revealed no evidence of harm to the fetus from enfuvirtide administered in doses up to 27 times and 3.2 times, respectively, the adult human daily dose on an m2 basis.
Placental and breast milk passage
Studies of radiolabeled enfuvirtide administered to lactating rats indicated radioactivity in the milk; however, it is not known if this reflected radiolabeled enfuvirtide or metabolites (such as amino acid and peptide fragments) of enfuvirtide. It is not known if enfuvirtide crosses the human placenta or is excreted in human milk. A published case report of two peripartum pregnant patients and their neonates and data from an ex vivo human placental cotyledon perfusion model suggest that enfuvirtide does not cross the placenta.1,2
Human studies in pregnancy
Very limited data exist on the use of enfuvirtide in pregnant women.1,3-5 There is a single case report detecting no placental transfer of drug based on cord blood measurements.5