reverse transcriptase inhibitors (NRTIs) 3TC and FTC are equally effective,
results of a meta-analysis and systematic review published in PLOS ONE show. Pooled results from
twelve randomised studies showed that the drugs were equivalent, with
near-identical rates of viral suppression for the drugs. The risk of
treatment failure was also the same for both antiretrovirals.
review of published and unpublished data from randomized trials found no
significant differences in the efficacy of lamivudine [3TC] and emtricitabine
[FTC]”, comment the authors. They suggest their findings are “consistent with
the very similar chemical structure of these two nucleoside analogues”.
international HIV treatment guidelines consider 3TC (lamivudine, Epivir, also in the combination pill Kivexa) and FTC (emtricitabine, Emtriva,
also in Truvada, Eviplera and Atripla) to have similar clinical
efficacy. The drugs form a core component of the NRTI 'backbone' of
antiretroviral combinations for people starting treatment for the first time (treatment naive) and people changing treatment (treatment experienced). However, some research has suggested that regimens including 3TC lack
the virological potency of combinations containing FTC. This means that there
is ongoing uncertainty about the clinical equivalence of the two drugs.
An international team
of investigators therefore conducted a systematic review and meta-analysis of
randomised studies to assess and compare the effectiveness of the drugs.
identified randomised and quasi-randomised studies in which 3TC and FTC were
used for the treatment of either treatment-naive or treatment-experienced
patients. They only included studies if they allowed direct comparison between
3TC and FTC. Therefore, the other drugs in the regimens taken by people
treated with 3TC or FTC had to be identical or comparable. Studies where
patients took abacavir (Ziagen, also
in Kivexa) and tenofovir (Viread, also in Truvada, Eviplera and Atripla) were
included but only if the study population did not start therapy with a viral
load above 100,000 copies/ml. This is because of evidence suggesting inferior
virological outcomes among people taking abacavir who have a viral load above
this level at the start of therapy.
A total of twelve
randomised studies with 15 different randomised comparisons met the inclusion
criteria and were included in the authors’ analyses. These studies provided
data on 2251 people taking 3TC and 2662 people taking FTC. The
studies were published between 2002 and 2013. Three studies directly compared
3TC with FTC.
rates were comparable in all twelve studies. The three studies that provided a
direct comparison between 3TC and FTC showed a non-significant difference in
the chances of treatment success (RR = 1.03; 95% CI, 0.96-1.10; p = 0.3).
Overall, the odds
of treatment success were identical (RR = 1.00; 95% CI, 0.97-10.2). Outcomes
did not differ by sub-group.
The risk of
treatment failure was also comparable for the two drugs (RR = 1.08; 95% CI,
0.94-1.22). Once again, the risk of failure did not differ in sub-group
Two of the three
studies with identical backbone regimens provided data on the rate of
side-effects. One of the studies showed there was no difference between 3TC and
FTC in the frequency of moderate and serious adverse events. In the other, 4%
of people taking FTC discontinued treatment but there were no
discontinuations among people taking 3TC.
findings provide supportive evidence for recommendations of current
international and national treatment guidelines to treat emtricitabine and
lamivudine as interchangeable,” the authors conclude. They believe their
results will provide “reassurance to countries that, for reasons of
affordability or availability have opted for lamivudine as part of first-line