skip navigation

Skip Nav

Clinical Guidelines Portal

Clinical Guidelines Portal

Table of Contents

Recommendations for Use of Antiretroviral Drugs in Pregnant HIV-1-Infected Women for Maternal Health and Interventions to Reduce Perinatal HIV Transmission in the United States

Entry Inhibitors

Enfuvirtide (Fuzeon, T-20)

(Last updated: August 6, 2015; last reviewed: August 6, 2015)

Enfuvirtide is classified as Food and Drug Administration Pregnancy Category B. 

Animal 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.

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 subcutaneously (1.6 times the maximum recommended adult human daily dose on a body surface area basis).

Teratogenicity/Developmental Toxicity
Studies in rats and rabbits have shown no evidence of teratogenicity or effect on reproductive function with enfuvirtide.1

Placental and Breast Milk Passage
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 a body surface area basis). 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 (amino acid and peptide fragments) of enfuvirtide. 

Human Studies in Pregnancy 

Data on the use of enfuvirtide in human pregnancy are limited to case reports of a small number of women treated with the drug.2-8

Placental and Breast Milk Passage
In vitro and in vivo studies suggest that enfuvirtide does not readily cross the human placenta. Published reports of a total of eight peripartum patients and their neonates and data from an ex vivo human placental cotyledon perfusion model demonstrated minimal placental passage of enfuvirtide.2,5,9-11 

Teratogenicity/Developmental Toxicity
In the Antiretroviral Pregnancy Registry and in a national cohort of pregnant women with HIV infection in Italy, insufficient numbers of first-trimester exposures to enfuvirtide in humans have been monitored to be able to make a risk determination.12,13

Excerpt from Table 7a
Generic Name
Trade Name
Formulation  Dosing Recommendations Use in Pregnancy

  • Supplied as lyophilized powder. Each vial contains 108 mg of T20; reconstitute with 1.1 mL of sterile water for injection for SQ delivery of approximately 90 mg/1 mL.
T20 is indicated for advanced HIV disease and must be used in combination with other ARVs to which the patient’s virus is susceptible by resistance testing.

Standard Adult Dose:
  • 90 mg (1 mL) twice daily without regard to meals
PK in Pregnancy:
  • No PK data in human pregnancy.
Dosing in Pregnancy:
  • Insufficient data to make dosing recommendation.
Minimal to low placental transfer to fetus.b

No data on human teratogenicity.

a Individual antiretroviral drug dosages may need to be adjusted in renal or hepatic insufficiency (for details, see Adult Guidelines, Appendix B, Table 7).
b Placental transfer categories—Mean or median cord blood/maternal delivery plasma drug ratio:
   High: >0.6
   Moderate: 0.3–0.6
   Low: <0.3

Key to Abbreviations: ARV = antiretroviral; PK = pharmacokinetic; SQ = subcutaneous; T20 = enfuvirtide


  1. Enfuvirtide (Fuzeon) [package insert]. Food and Drug Administration. 2012. Available at Accessed July 1, 2015.
  2. Brennan-Benson P, Pakianathan M, Rice P, et al. Enfurvitide prevents vertical transmission of multidrug-resistant HIV-1 in pregnancy but does not cross the placenta. AIDS. 2006;20(2):297-299. Available at
  3. Cohan D, Feakins C, Wara D, et al. Perinatal transmission of multidrug-resistant HIV-1 despite viral suppression on an enfuvirtide-based treatment regimen. AIDS. 2005;19(9):989-990. Available at
  4. Meyohas MC, Lacombe K, Carbonne B, Morand-Joubert L, Girard PM. Enfuvirtide prescription at the end of pregnancy to a multi-treated HIV-infected woman with virological breakthrough. AIDS. 2004;18(14):1966-1968. Available at
  5. Weizsaecker K, Kurowski M, Hoffmeister B, Schurmann D, Feiterna-Sperling C. Pharmacokinetic profile in late pregnancy and cord blood concentration of tipranavir and enfuvirtide. Int J STD AIDS. 2011;22(5):294-295. Available at
  6. Furco A, Gosrani B, Nicholas S, et al. Successful use of darunavir, etravirine, enfuvirtide and tenofovir/emtricitabine in pregnant woman with multiclass HIV resistance. AIDS. 2009;23(3):434-435. Available at
  7. Sued O, Lattner J, Gun A, et al. Use of darunavir and enfuvirtide in a pregnant woman. Int J STD AIDS. 2008;19(12):866-867. Available at
  8. Madeddu G, Calia GM, Campus ML, et al. Successful prevention of multidrug resistant HIV mother-to-child transmission with enfuvirtide use in late pregnancy. Int J STD AIDS. 2008;19(9):644-645. Available at
  9. Ceccaldi PF, Ferreira C, Gavard L, Gil S, Peytavin G, Mandelbrot L. Placental transfer of enfuvirtide in the ex vivo human placenta perfusion model. Am J Obstet Gynecol. 2008;198(4):433 e431-432. Available at
  10. Peters PJ, Polle N, Zeh C, et al. Nevirapine-associated hepatotoxicity and rash among HIV-infected pregnant women in Kenya. J Int Assoc Physicians AIDS Care (Chic). 2012;11(2):142-149. Available at
  11. Moisan A, Desmoyer A, Bourgeois-Moine A, et al. Placental transfer of antiretroviral drugs in HIV-infected women: a retrospective study from 2002 to 2009. Abstract 1. Presented at: 11th International Workshop on Clinical Pharmacology of HIV Therapy. 2010. Sorrento, Italy.
  12. Antiretroviral Pregnancy Registry Steering Committee. Antiretroviral Pregnancy Registry international interim report for 1 Jan 1989–31 July 2014. Wilmington, NC: Registry Coordinating Center. 2014. Available at
  13. Floridia M, Mastroiacovo P, Tamburrini E, et al. Birth defects in a national cohort of pregnant women with HIV infection in Italy, 2001–2011. BJOG. 2013;120(12):1466-1475. Available at

Back to Top