title: FEM-PrEP: adherence patterns and factors associated with adherence to a daily oral study product for pre-exposure prophylaxis.
abstract: BACKGROUND
  Several clinical trials have demonstrated the safety and effectiveness of oral tenofovir disoproxil fumarate (TDF), with or without emtricitabine (FTC), as pre-exposure prophylaxis (PrEP) for reducing the risk of HIV acquisition. Adherence to the study product was insufficient to demonstrate the effectiveness of FTC/TDF in 2 PrEP clinical trials conducted among women (FEM-PrEP and the Vaginal and Oral Interventions to Control the Epidemic study), but further analyses of adherence in these studies may inform PrEP demonstration projects and future HIV prevention clinical trials.
  
  
  METHODS
  We randomly selected a subcohort of 150 participants randomized to FTC/TDF in 3 FEM-PrEP sites (Bondo, Kenya; Bloemfontein, South Africa; and Pretoria, South Africa) to examine adherence levels over time and to assess factors associated with adherence, based on plasma tenofovir and intracellular tenofovir diphosphate drug concentrations in specimens collected at 4-week visit intervals.
  
  
  RESULTS
  We observed drug concentrations consistent with good adherence in 28.5% of all visit intervals when drug was available to use, but only 12% of participants achieved good adherence throughout their study participation. In multivariate analysis, the Bloemfontein site [odds ratio (OR): 2.43; 95% confidence interval (CI): 1.32 to 4.48] and liking the pill color (OR: 2.93; 95% CI: 1.18 to 7.27) were positively associated with good adherence, whereas using oral contraceptive pills at enrollment was negatively associated with good adherence (OR: 0.37; 95% CI: 0.18 to 0.74).
  
  
  CONCLUSIONS
  Most participants did not regularly adhere to the study product throughout their trial participation, although a small minority did. Few factors associated with good adherence to the study product were identified in FEM-PrEP.
authors.affiliation: Departments of *Social and Behavioral Health Sciences, †Clinical Sciences, and ‡Quantitative Sciences, FHI 360, Durham, NC; §Setshaba Research Centre, Soshanguve, South Africa; ‖Impact Research and Development Organization, Kisumu, Kenya; ¶Josha Research, Bloemfontein, South Africa; #Kilimanjaro Christian Medical Center, Moshi, Tanzania; and **Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC (Van Damme is now with the Bill & Melinda Gates Foundation, Seattle, WA).
authors.forename: Amy L
authors.initials: AL
authors.lastname: Corneli
authors.forename: Jennifer
authors.initials: J
authors.lastname: Deese
authors.forename: Meng
authors.initials: M
authors.lastname: Wang
authors.forename: Doug
authors.initials: D
authors.lastname: Taylor
authors.forename: Khatija
authors.initials: K
authors.lastname: Ahmed
authors.forename: Kawango
authors.initials: K
authors.lastname: Agot
authors.forename: Johan
authors.initials: J
authors.lastname: Lombaard
authors.forename: Rachel
authors.initials: R
authors.lastname: Manongi
authors.forename: Saidi
authors.initials: S
authors.lastname: Kapiga
authors.forename: Angela
authors.initials: A
authors.lastname: Kashuba
authors.forename: Lut
authors.initials: L
authors.lastname: Van Damme
mesh_terms: D000225:Adenine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood / Q000627:therapeutic use; D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D019380:Anti-HIV Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D003841:Deoxycytidine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000627:therapeutic use; D000068679:Emtricitabine; D005260:Female; D015658:HIV Infections / Q000517:prevention & control*; D006801:Humans; D016015:Logistic Models; D008297:Male; D015999:Multivariate Analysis; D063065:Organophosphonates / Q000008:administration & dosage / Q000097:blood / Q000627:therapeutic use*; D012307:Risk Factors; D000068698:Tenofovir; D055815:Young Adult; D016903:Drug Monitoring
chemical_list: D019380:Anti-HIV Agents; D063065:Organophosphonates; D003841:Deoxycytidine; D000068698:Tenofovir; D000068679:Emtricitabine; D000225:Adenine