Durability of emtricitabine vs. lamivudine in patients enrolled in a large cohort in Italy starting tenofovir containing combination antiretroviral therapy (cART)
Background: A
difference in the rate of discontinuation of lamivudine (3TC)- and emtricitabine
(FTC)-containing cART has been hypothesized but no randomized comparison exists.
Methods:
We included HIV-infected patients enrolled in 50 participating
Italian clinical centres (Icona Foundation Study) who started 3TC or FTC with
tenofovir+NNRTI or PI/r. Characteristics of patients receiving either 3TC or
FTC were compared using Chi-square and Wilcoxon test. Time to discontinuation
(FTC/3TC component or any drugs/regardless of reason) was compared between the
two groups using Kaplan-Meier (KM) plots and Cox regression.
Results: We
studied a total of 266 patients on 3TC/tenofovir (58% starting from ART-naïve)
and 1007 on FTC/tenofovir (85% ART-naïve). 95% of patients on FTC used the
fixed dose combination (FTC) truvada. Patients receiving FTC were less likely
to be female (25% vs. 35%, p=0.001) co-infected with HCV (14% vs. 27%, p=0.001)
and more likely to be ART-naïve (85% vs. 58%, p=0.001) and have started a PI/r (60%
vs. 34%, p=0.001). The median calendar year of start was 2004 (IQR:2004-2005)
for 3TC vs. 2008 (2007-2009) for FTC (p=0.0001). In ART-naïve patients the KM
estimates of discontinuing 3TC or FTC alone by 24 months were: 3TC:38%, FTC:43%
(p=0.21). Relative hazards (RH) are shown in Table. Similar results were found
when restricting to pre-treated patients
| Discontinuation regardless of the reason (ART-naïve) | Crude RH (95% CI) | p-value | Adjusted* RH (95% CI) | p-value |
| FTC/3TC component FTC vs. 3TC | 1.13 (0.86, 1.50) | 0.39 | 0.64 (0.40, 1.02) | 0.06 |
| Any drug FTC vs. 3TC | 1.40 (1.08, 1.83) | 0.01 | 0.83 (0.54, 1.27) | 0.38 |
*adjusted for age, gender, nationality, mode of HIV transmission, hepatitis co-infection, 3rd drug started, AIDS diagnosis, baseline CD4 count and viral load, year of starting cART; stratified by clinical center
Conclusions:
In our analysis, FTC (predominantly used as FTC of truvada) and the drugs used in combination tended to be discontinued less frequently than 3TC and those in 3TC-combinations, although unmeasured confounding cannot be ruled out.
A. d'Arminio Monforte1, A. Cozzi-Lepri2, M. Puoti3, M. Arlotti4, P. Narciso5, A. Gori6, P. Caramello7, A. Chiodera8, A. De Luca9, A. Antinori5, Icona Foundation
1University of Milan, San Paolo Hospital, Infectious and Tropical Diseases, Milan, Italy, 2University College London, Coordinating Center for Biometric Research Division of Biostatistics, Minneapolis, United States, 3Niguarda Hospital, Infectious Diseases, Milan, Italy, 4Infermi Hospital, Infectious Diseases, Rimini, Italy, 5National Insitute of Infectious Diseases L. Spallanzani, Infectious Diseases, Rome, Italy, 6San Gerardo Hospital, University of Milan-Bicocca, Infectious Diseases, Monza, Italy, 7Amedeo di Savoia Hospital, Infectious Diseases, Turin, Italy, 8Macerata Hospital, Infectious Diseases, Macerata, Italy, 9Università Cattolica del S Cuore, Roma - Azienda Ospedaliera Universitaria Senese, Infectious Diseases, Siena, Italy