title: Candidates for inclusion in a universal antiretroviral regimen: are lamivudine and emtricitabine interchangeable?
abstract: OBJECTIVE
  Lamivudine (3TC) and emtricitabine (FTC) are the most widely used antiretroviral medications worldwide and are considered by the WHO to be interchangeable. This article reviews evidence supporting interchangeability of 3TC and FTC and considerations for future use.
  
  
  RESULTS
  Three randomized trials have directly compared the safety and efficacy of 3TC and FTC against identical backbone regimens. Each of these trials reported a nonsignificant difference in virological suppression, and when results were pooled the overall difference was nonsignificant (relative risk 1.03, 95% confidence interval 0.96-1.10). These findings of equivalence are further supported by indirect evidence from nine randomized trials comparing 3TC and FTC against a similar backbone regimen of two different nucleoside reverse transcriptase inhibitors (relative risk of virological suppression 0.99, 95% confidence interval 0.96-1.01). Data from observational studies is mixed. Overall, reported differences between 3TC and FTC in observational studies are often associated with differences in the baseline characteristics of the treatment groups, notably with respect to immunological and virological status, comorbidity, substance misuse, and pill burden.
  
  
  CONCLUSIONS
  The totality of evidence to date, from pharmacological data to observational studies to direct and indirect comparisons in randomized trials, suggests that 3TC and FTC can be considered to be therapeutically interchangeable and that if there are any differences, these are likely to be very small and not of major clinical importance.
authors.affiliation: aDepartment of HIV and Global Hepatitis Programme, World Health Organization, Geneva, Switzerland bDivision of Pharmacology, Discipline of Pharmaceutical Sciences, University of KwaZulu-Natal, Durban, South Africa.
authors.forename: Nathan
authors.initials: N
authors.lastname: Ford
authors.forename: Marco
authors.initials: M
authors.lastname: Vitoria
authors.forename: Meg
authors.initials: M
authors.lastname: Doherty
authors.forename: Andy
authors.initials: A
authors.lastname: Gray
mesh_terms: D019380:Anti-HIV Agents / Q000627:therapeutic use*; D003841:Deoxycytidine; D000068679:Emtricitabine / Q000627:therapeutic use*; D015658:HIV Infections / Q000188:drug therapy*; D015497:HIV-1; D006801:Humans; D019259:Lamivudine / Q000627:therapeutic use*; D018894:Reverse Transcriptase Inhibitors / Q000627:therapeutic use*; D016896:Treatment Outcome
chemical_list: D019380:Anti-HIV Agents; D018894:Reverse Transcriptase Inhibitors; D003841:Deoxycytidine; D019259:Lamivudine; D000068679:Emtricitabine