Tenofovir (Viread)

Published October 02, 2001; Updated February 2013
Susa Coffey, MD
http://hivinsite.ucsf.edu/InSite?page=ar-01-07
Selected Reference
10. Landman  R, Descamps  D, Peytavin  G, Trylesinski  A, Katlama  C, Girard  PM, Bonnet  B, Yeni  P, Bentata  M, Michelet  C, Benalycherif  A, Brun Vezinet  F, Miller  MD, Flandre  P; TONUS (IMEA 021) Study Group.
Early virologic failure and rescue therapy of tenofovir, abacavir, and lamivudine for initial treatment of HIV-1 infection: TONUS study. HIV Clin Trials. 2005 Nov-Dec;6(6):291-301
[PubMed ID: 16452063]
Abstract:
BACKGROUND: To assess the efficacy and safety of the triple NRTI combination of abacavir (ABC), lamivudine (3TC), and tenofovir (TDF) in a once-daily regimen. METHOD: 38 HIV-naive patients (pts) were treated in a prospective open-arm study over 48 weeks (W48). Virological failure was defined as never achieving plasma HIV-1 RNA < 400 copies/mL or rebound of > or = 0.7 log10. RESULTS: 12/36 (33%) pts had virologic failure at W24 and 10 additional pts had HIV RNA > 50 copies/mL at W12 or W24. There was a significant association between baseline viral load (VL) and virologic failure in 0%, 29%, and 64% pts with baseline VL levels < 4, 4-5, and > 5 log10 copies/mL, respectively (p = .014). 76% of pts developed K65R and M184V/I mutations by W24, and 19% developed M184V/I alone. At W4, 86% of pts had adequate plasma Cmin for the 3 drugs. 14 pts with K65R and M184V/I were given a rescue therapy with a successful outcome (< 50 copies/mL; median follow-up 48 weeks). CONCLUSION: Convergent genetic pathway to resistance, in conjunction with lower antiretroviral potency, may explain the high rate of selection K65R and M184V mutations. These mutations did not appear to have a negative effect on rescue therapy with a variety of regimens.