Table 1. Oral PrEP drugs for the prevention of HIV infection.

Study, design, country and target population	Product & Dosage Form and dosing strategy	HIV risk reduction (Effectiveness)	Adherence Measure	Adherence Estimates	Type of adherence counseling	Potential barrier to adherence
TDF2 Trial[17], Phase III RCT, Botswana Men and women 18-39 years (n=1219)	TDF-FTC 1 tablet daily	62.2% (95% CI: 21.5- 83.4%)	Self-report Pill count Drug levels	94.4% (3 day recall) 84.1% 80%	Standard ASP	AE’s: nausea, vomiting, dizziness higher in TDF- FTC arm Highly migratory population
iPrEx [21, 23, 25, 50, 51] Phase III RCT, Brazil, Ecuador, Peru, South Africa, Thailand, USA MSM and transgender women ≥18 years (n=2499)	TDF-FTC 1 tablet daily	44% (95% CI: 15- 63%)	Self-report (interview and CASI) Pill count Medication Possession Ratio (MPR) Drug levels (sub- group of patients)	95% 85-95% Drug levels: Hair : 72% TFV , 74% FTC Plasma/PBMC: 54%	Structured ASP (Next-Steps counseling) (from Nov 2009- Feb 2010)	Age < 25 years AE’s: nausea in first 4 weeks of PrEP Social stigma if thought to be HIV positive Unintentional disclosure of sexual orientation
HPTN 052[18], Phase III RCT, Brazil, India, Kenya, Malawi, South Africa Zimbabwe ,Thailand, USA Serodiscordant couples (n=1763 couples)	Pre-specified combination of ARV (3TC , AZT, NVP, EFV, ATV, ddI, d4T, LPV/r, TDF or TDF- FTC) administered to the HIV Infected partner early vs late Tablets - daily or twice daily depending on drug regimen selected	96% (95% CI: 73-99%)	Self-report Pill count	Not reported >95% in 79% early arm >95% in 74% delayed arm	Standard ASP	Pill burden, AE’s- ARV related side effects more frequent in the early treatment than delayed treatment group
FEM PrEP[20, 24] Phase III RCT, Kenya, South Africa, Tanzania Women 18-35 years (n=1951)	TDF-FTC 1 tablet daily	HR: 0.94 (95%CI:0.59- 1.52) Stopped for futility	Self-report Pill count Drug levels (pre- specified analysis in seroconverters)	95% 88% 26% (7/26)- drug detected at beginning of infection window and 7/33 (21%) at end of window, and in 4/27 (15%) at both visits	Standard ASP	Low risk perception
Partners PrEP[12, 24] Phase III, RCT, Kenya, Uganda Heterosexual men, women serodiscordant couples >18years (n=4747 couples)	TDF TDF-FTC 1 tablet daily	TDF: 67% (95% CI: 44- 81%) TDF/FTC: 75% (95% CI: 55- 87%)	Self-report Pill count Drug levels Adherence sub- study: MEMS UPC and in depth interview	Not reported 97% , when adjusted for other factors then 92.1% 82% in random sample92% 99%	Standard ASP - Individualized counseling as required	AE’s- nausea and diarrhea Off study product during pregnancy and breastfeeding
MTN 003 (VOICE)[13, 14] Phase IIb RCT, South Africa, Uganda, Zimbabwe Women 18-45 years (n=5029)	TDF TDF-FTC 1 tablet daily	TDF: HR 1.49 (95% CI: 0.97-2.29) TDF-FTC: HR 1.04 (95% CI: 0.73-1.49)	Self- report (interview and ACASI) Pill count Drug levels in plasma (case-cohort subset)	TDF-FTC: 91% TDF: 90% TDF-FTC: 92% TDF: 87% TDF: 28% TDF-FTC: 29%	Structured ASP (VASP)	Daily use of product Young and unmarried Low risk perception
Pilot safety, acceptability, and adherence [19] Phase I//II RCT, Kenya MSM, FSW, 18-49 years (n=72)	TDF-FTC 1 tablet daily or Intermittent dosing: 1 tablet Mon and Fri plus post-coital dose (not exceeding one dose a day)	N/A	Self-report: post- coital dose MEMS Drug levels: plasma, PBMC	100% (using timeline- follow back self-report and sexual activity data) Daily dosing: 83%, Intermittent dosing: 68% Post-coital: 26% Analysis pending	Standard individualized ASP	Difficulty in remembering to take intermittent doses Perception of risk Alcohol use prior to sex Disclosure of PrEP use to partner Transactional sex-may not have product accessible for post coital dose
Bangkok Tenofovir Study [15, 16] Phase III RCT Bangkok IDU, men and women 20-60 years (n=2413)	TDF 1 tablet daily	48.9% (95%CI: 9.6-72.2)	Pill count and patient medication diary Self –report (non- DOT) DOT- TDF adherence card Drug levels	83.8% 100% 94.8% 70% reduction in risk if levels detectable	Structured ASP (individualized)	Side-effects: nausea Incarceration

RCT= randomised controlled trial, AE’s = adverse events, ,CI= confidence interval, MSM= men who have sex with men, CASI=computer assisted self-interview, ASP= adherence support programme, MEMS-medication event monitoring system, UPC- unannounced home visit pill counts, ACASI= audio computer assisted self-interview , FSW= female sex workers, IDU= injection drug users, DOT= directly observed treatment , VASP= VOICE Adherence Strengthening Program. 3T= lamivudine , AZT=zidovudine, NVP=nevirapine, EFV= efavirenz,, ATV= atazanavir, ddI= didanosine, d4T= stavudine, LPV/r = lopinavir/ritonavir, TDF= tenofovir disoproxil fumarate or TDF-FTC = tenofovir disporoxil fumarate-emtricitabine. Unless otherwise stated all RCTs are placebo-controlled