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Durability of emtricitabine vs. lamivudine in patients enrolled in a large cohort in Italy starting tenofovir containing combination antiretroviral therapy (cART)
Abstract Content:
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
[FTC]
*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.
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.