CClinicalTrials.gg
CompletedNCT04318210TDF2-OLEUpdated May 13, 2022Results posted

Open Label Extension (OLE) of the TDF2 Study, Botswana

An interventional study of Tenofovir Disoproxil Fumarate 300 mg + Emtricitabine 200 mg in HIV Infections, sponsored by Centers for Disease Control and Prevention. Completed. Open to participants aged 18 Years to 64 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2022-05-13.

Sponsored by Centers for Disease Control and Prevention · Not applicable, Interventional, and Prevention

From the registry’s dates

  • Registered 7 years 5 months after the study started (first participant enrolled Oct 2012, registered Mar 2020).
Phase
Not applicable
Study type
Interventional
Enrollment
229
Allocation
Not applicable
Ages
18 Years to 64 Years
Sex
All
01

Study summary

This study is an open label and is an extension to the TDF2 study in which the investigators offered daily oral tenofovir/emtricitabine (TDF/FTC) for a maximum of 12 months to HIV uninfected former participants of the TDF2 study.

Read the detailed description

This open label phase builds on a unique opportunity provided by the end of the randomized phase of the TDF 2 study. The randomized study provided a well-characterized cohort of persons who received standard prevention interventions, including monthly testing, counseling, and condoms. The primary intervention that will change in the open label phase is the provision of information about the demonstrated efficacy and safety of PrEP including counseling about how PrEP is not 100% effective, provision of open label rather than blinded study medication, and a shortened visit schedule designed to more closely approximate what would be feasible in an implementation program. This open label phase will therefore serve as an opportunity to gather additional information relevant to the delivery and uptake of daily oral PrEP that may help inform eventual more wide scale PrEP implementation in Botswana.The OLE also leverages unique opportunities to address important questions about how information about PrEP safety and efficacy might affect risk behavior. The randomized trial showed that condom use (81.9% in the TDF/FTC group and 79.7% in the placebo group, p = 0.21) and the number of participants with more than one sexual partner in the previous month (14.2% in the TDF/FTC group and 14.1% in the placebo group, p = 0.86) between the two groups was similar. The underlying premise of this OLE is that information about PrEP efficacy and the knowledge of taking active drug rather than placebo might alter perception of HIV risk. This extension seeks to determine whether this trend will occur in the cohort after individuals receive information and counseling about the partial protective efficacy of PrEP and to identify risk factors for changes in risk behavior. The randomized trial revealed that reported drug adherence between the two arms was almost identical at 84.1% in the TDF/FTC group and 83.7% in the placebo arm (p = 0.79). The investigators have designed this open label phase in order to determine 1) if the knowledge of receiving active drug and the receipt of information about PrEP safety and partial efficacy at the onset of the open label phase could have substantial effects on pill use and 2) to identify individual factors associated with this impact. In addition, the open label extension will provide more information about the long term safety of Truvada.

02

Conditions studied

  • HIV Infections

Keywords

  • HIV incidence
  • HIV prevention
  • Tenofovir
  • Emtricitabine
  • Botswana
  • HIV seronegativity
  • PrEP
03

In context

Infections

6,687 studies on the registry are indexed under Infections; 807 are open to participants now.

This study's enrollment of 229 is above the median of 120 across 4,200 interventional studies indexed under Infections.

Browse Infections studies →

Lead sponsor

Centers for Disease Control and Prevention is the lead sponsor of 273 studies on the registry; 2 are open to participants now.

Of its 11 completed or terminated interventional studies of FDA-regulated products, 8 (73%) have results posted.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years to 64 Years
Sexes eligible
All
Accepts healthy volunteers
Yes

Inclusion criteria

  • Former TDF 2 participants
  • Willing and able to provide informed written consent for participation
  • If female, willing to use effective contraception during the trial (oral or injectable hormonal contraception, an intrauterine device [IUD], or who have had surgical interventions such as bilateral tubal ligation or hysterectomy)
  • Laboratory values as follows within 30 days prior to enrollment:
  • HIV uninfected by dual, parallel, rapid whole blood testing and HIV EIA
  • Serum phosphorus ≥ 2.2 mg/dL
  • Calculated creatinine clearance ≥ 60 mL/min

Exclusion criteria

Exclusion Criteria:

  • Positive urine pregnancy test (females)
  • Breastfeeding (females)
  • History of significant renal or bone disease
  • Any other clinical condition or prior therapy that, in the opinion of the physician would make the subject unsuitable for the OLE or unable to comply with the dosing requirements
05

Study design

Phase
Not applicable
Primary purpose
Prevention
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrollment
229 participants (actual)

Study arms

  • Experimental
    TDF-FTC as PrEP

    Eligible HIV-uninfected participants were offered 12 months of oral Tenofovir Disoproxil Fumarate 300 mg + Emtricitabine 200 mg (TDF-FTC) once daily in the form of a single tablet regardless of their original study assignment in randomized phase.

    Drug: Tenofovir Disoproxil Fumarate 300 mg + Emtricitabine 200 mg

Interventions

  • DrugTenofovir Disoproxil Fumarate 300 mg + Emtricitabine 200 mg

    Also known as: Truvada

06

What researchers measure

Primary outcomes

  1. Self-reported Drug Adherence Over the Past 3 Days

    A 30-day supply of TDF/FTC was dispensed at each monthly visit, for up to 12 months. Participants were asked monthly about their drug adherence and were asked to recall their time of dosing over the past 3 days. Question: "Please think back to \[yesterday, 2 days ago, 3 days ago\]. What time did you take Truvada? Was it in the morning, afternoon, evening, or you weren't able to take the pill that day?"

    Time frame: Up to 12 Months

  2. Number of Sex Partners

    Number of sex partners was assessed at baseline and each scheduled monthly visit, for up to 12 months. Responses to the following question refers to the number of partners reported in the past 30 days: "In the past 30 days, with how many partners have you had sexual intercourse?"

    Time frame: Up to 12 months

  3. Number of Sex Acts by Condom Usage

    Number of sex acts by condom usage was assessed at baseline and each scheduled monthly visit, for up to 12 months. Responses to the following question refers to the number of sex acts with up to 3 partners. "In the past 30 days, how many times did you have sex with \['this partner'\]? When I ask about the number of times you had sex, please count each sexual act. For example, if you had 2 rounds of sexual intercourse with your partner on a single evening, count that as two times you had sex. Please remember that this only refers to vaginal and anal sex. It does not refer to oral sex." To assess condom use by sex act, the following question was asked to assess the number of sex acts with condoms and without condoms with up to 3 partners: "Of the ___ sex acts, how many times did you not use condoms the entire time?"

    Time frame: Up to 12 months

  4. Extracellular Tenofovir (TFV) for Recent Drug Exposure

    Dried blood spots were collected at each monthly study visit to characterize drug adherence by measuring extracellular tenofovir (TFV) for recent drug exposure (\~24 hours). Of 229 participants, 196 participants had monthly DBSs available for analysis. A sampling algorithm was designed to make inference to TFV and TFV-DP levels at all 12 months. For the TFV extracellular analysis, participants were randomly assigned to one of three sampling schedules, with equal probability: (a) months 1, 2, 5, 8, and 11; (b) months 1, 3, 6, 9, and 12; and (c) months 1, 4, 7, 10, and 12. These 196 participants contributed a total of 777 monthly DBSs for the TFV extracellular analysis. Extracellular TFV detectability was defined as having a mean TFV level (of up to four measurements) equal to or greater than 5 ng/mL.

    Time frame: Up to 12 months

  5. Intracellular Tenofovir-diphosphate (TFV-DP)

    Dried blood spots were collected at each monthly study visit to characterize drug adherence by measuring intracellular tenofovir-diphosphate (TFV-DP) for long-term drug exposure (\~7 days). The 196 participants who had monthly DBSs available were stratified by site, gender, and the 3 patterns previously assigned for the TFV extracellular analysis (2×2×3 = 12 strata). Then 60 participants were selected, 5 from each of the 12 strata, to balance by site, gender, and the above 3 patterns were maintained. In turn, the monthly DBSs indicated by the assigned pattern were analyzed. These 60 participants contributed a total of 237 monthly DBSs for the TFV-DP intracellular analysis. The observed TFV-DP levels in our study population were categorized as follows (units of drug in fmol/mL): 0 doses per week (\<912); 1 dose taken per week (≥912 and \<1824); 2 doses taken per week (≥1824 and \<2688); 3 doses taken per week (≥2688 and \<3600); 4 doses taken per week (≥3600 and \<4464); 5 to 7 doses taken

    Time frame: Up to 12 months

Secondary outcomes

  1. HIV Seroconversion

    Study visits were scheduled every month until completion of the study and during monthly study visits, HIV testing was performed, for up to 12 months. During monthly visits, routine HIV testing was performed with two HIV rapid tests. If HIV-infection was suspected, HIV antigen-antibody (Ag/Ab) combination enzyme immunoassay (EIA) (Bio-Rad, GS HIV Combo Ag/Ab EIA) testing was performed, and RNA viral load was measured.

    Time frame: Up to 12 Months

  2. Serious Adverse Events

    Study visits were scheduled every month until study completion. Participants were instructed to return to the clinic for evaluation in event of illness. Participants reported any adverse effects (AEs) at monthly or interim visits and were determined as serious adverse events (SAE) when at least possibly related to study drug. DAIDS Table for Grading Severity of Adult Adverse Experiences for Vaccine \& Prevention Research Programs was used for grading. Definitions: Grade 3-'probably related'-strong temporal relationship to study product that cannot be explained by participant's clinical state or other factors and a causal relationship is biologically plausible. Grade 4-'definitely related'-distinct temporal relationship to administration of the study product that cannot be explained by the participant's clinical state or other factors or AE occurs on re-challenge or the AE is a known reaction to the product or chemical group or can be predicted by the product's pharmacology.

    Time frame: Up to 12 Months

07

Results

Posted May 13, 2022

Participant flow

Participant flow — Overall Study
MilestoneTDF-FTC as PrEP
Started229
Completed153
Not completed76

Outcome measures

PrimarySelf-reported Drug Adherence Over the Past 3 Days

A 30-day supply of TDF/FTC was dispensed at each monthly visit, for up to 12 months. Participants were asked monthly about their drug adherence and were asked to recall their time of dosing over the past 3 days. Question: "Please think back to \[yesterday, 2 days ago, 3 days ago\]. What time did you take Truvada? Was it in the morning, afternoon, evening, or you weren't able to take the pill that day?"

Time frame:
Up to 12 Months
Reported as:
Count of participants · Participants
Self-reported Drug Adherence Over the Past 3 Days
ParticipantsTDF-FTC as PrEP
Took daily dosage in past 3 days199
Took 2 doses in past 3 days9
Took 1 doses in past 3 days2
No doses taken in past 3 days19
PrimaryNumber of Sex Partners

Number of sex partners was assessed at baseline and each scheduled monthly visit, for up to 12 months. Responses to the following question refers to the number of partners reported in the past 30 days: "In the past 30 days, with how many partners have you had sexual intercourse?"

Time frame:
Up to 12 months
Reported as:
Mean · sexual partners
Number of Sex Partners
sexual partnersTDF-FTC as PrEP
Number of sex partners among women, overall0.87 ± 0.53
Number of sex partners among men, overall1.03 ± 0.74
PrimaryNumber of Sex Acts by Condom Usage

Number of sex acts by condom usage was assessed at baseline and each scheduled monthly visit, for up to 12 months. Responses to the following question refers to the number of sex acts with up to 3 partners. "In the past 30 days, how many times did you have sex with \['this partner'\]? When I ask about the number of times you had sex, please count each sexual act. For example, if you had 2 rounds of sexual intercourse with your partner on a single evening, count that as two times you had sex. Please remember that this only refers to vaginal and anal sex. It does not refer to oral sex." To assess condom use by sex act, the following question was asked to assess the number of sex acts with condoms and without condoms with up to 3 partners: "Of the ___ sex acts, how many times did you not use condoms the entire time?"

Time frame:
Up to 12 months
Reported as:
Mean · sex acts
Number of Sex Acts by Condom Usage
sex actsTDF-FTC as PrEP
Number of sex acts among women4.01 ± 5.26
Number of sex acts among men5.95 ± 6.67
Number of condomless sex acts among women1.28 ± 3.72
Number of condomless sex acts among men1.70 ± 4.34
Number of sex acts involving a condom among women2.72 ± 3.70
Number of sex acts involving a condom among men4.24 ± 5.19
PrimaryExtracellular Tenofovir (TFV) for Recent Drug Exposure

Dried blood spots were collected at each monthly study visit to characterize drug adherence by measuring extracellular tenofovir (TFV) for recent drug exposure (\~24 hours). Of 229 participants, 196 participants had monthly DBSs available for analysis. A sampling algorithm was designed to make inference to TFV and TFV-DP levels at all 12 months. For the TFV extracellular analysis, participants were randomly assigned to one of three sampling schedules, with equal probability: (a) months 1, 2, 5, 8, and 11; (b) months 1, 3, 6, 9, and 12; and (c) months 1, 4, 7, 10, and 12. These 196 participants contributed a total of 777 monthly DBSs for the TFV extracellular analysis. Extracellular TFV detectability was defined as having a mean TFV level (of up to four measurements) equal to or greater than 5 ng/mL.

Time frame:
Up to 12 months
Reported as:
Number · number of DBS samples
Extracellular Tenofovir (TFV) for Recent Drug Exposure
number of DBS samplesTDF-FTC as PrEP
Detectable TFV713
No detectable TFV64
PrimaryIntracellular Tenofovir-diphosphate (TFV-DP)

Dried blood spots were collected at each monthly study visit to characterize drug adherence by measuring intracellular tenofovir-diphosphate (TFV-DP) for long-term drug exposure (\~7 days). The 196 participants who had monthly DBSs available were stratified by site, gender, and the 3 patterns previously assigned for the TFV extracellular analysis (2×2×3 = 12 strata). Then 60 participants were selected, 5 from each of the 12 strata, to balance by site, gender, and the above 3 patterns were maintained. In turn, the monthly DBSs indicated by the assigned pattern were analyzed. These 60 participants contributed a total of 237 monthly DBSs for the TFV-DP intracellular analysis. The observed TFV-DP levels in our study population were categorized as follows (units of drug in fmol/mL): 0 doses per week (\<912); 1 dose taken per week (≥912 and \<1824); 2 doses taken per week (≥1824 and \<2688); 3 doses taken per week (≥2688 and \<3600); 4 doses taken per week (≥3600 and \<4464); 5 to 7 doses taken

Time frame:
Up to 12 months
Reported as:
Number · number of DBS samples
Intracellular Tenofovir-diphosphate (TFV-DP)
number of DBS samplesTDF-FTC as PrEP
7 doses per week141
6 doses per week29
5 doses per week20
4 doses per week6
3 doses per week12
2 doses per week4
1 dose per week5
0 doses per week19
SecondaryHIV Seroconversion

Study visits were scheduled every month until completion of the study and during monthly study visits, HIV testing was performed, for up to 12 months. During monthly visits, routine HIV testing was performed with two HIV rapid tests. If HIV-infection was suspected, HIV antigen-antibody (Ag/Ab) combination enzyme immunoassay (EIA) (Bio-Rad, GS HIV Combo Ag/Ab EIA) testing was performed, and RNA viral load was measured.

Time frame:
Up to 12 Months
Reported as:
Count of participants · Participants
HIV Seroconversion
ParticipantsTDF-FTC as PrEP
HIV Seroconversion0
SecondarySerious Adverse Events

Study visits were scheduled every month until study completion. Participants were instructed to return to the clinic for evaluation in event of illness. Participants reported any adverse effects (AEs) at monthly or interim visits and were determined as serious adverse events (SAE) when at least possibly related to study drug. DAIDS Table for Grading Severity of Adult Adverse Experiences for Vaccine \& Prevention Research Programs was used for grading. Definitions: Grade 3-'probably related'-strong temporal relationship to study product that cannot be explained by participant's clinical state or other factors and a causal relationship is biologically plausible. Grade 4-'definitely related'-distinct temporal relationship to administration of the study product that cannot be explained by the participant's clinical state or other factors or AE occurs on re-challenge or the AE is a known reaction to the product or chemical group or can be predicted by the product's pharmacology.

Time frame:
Up to 12 Months
Reported as:
Number · participants
Serious Adverse Events
participantsTDF-FTC as PrEP
Hyperamylasemia, Grade 32
Hypophosphatemia, Grade 35
Hypercreatininemia, Grade 11

Adverse events

Collected over Adverse event data was collected over the period of 12 months.. Non-serious events are listed at a 5% frequency threshold.

Adverse event summary by group
GroupDeathsSeriousOther
TDF-FTC as PrEP—8/229 (3.5%)169/229 (73.8%)
Most frequent serious events
Most frequent serious events
EventTDF-FTC as PrEP
HypophosphatemiaBlood and lymphatic system disorders5/229
HyperamylasemiaBlood and lymphatic system disorders2/229
Elevated creatinineRenal and urinary disorders1/229
Most frequent other events
Most frequent other events
EventTDF-FTC as PrEP
HyperamylasemiaBlood and lymphatic system disorders126/229
HypophosphatemiaBlood and lymphatic system disorders58/229
TransaminitisGastrointestinal disorders22/229
HeadacheGeneral disorders21/229
HyperbilirubinemiaBlood and lymphatic system disorders17/229
DizzinessNervous system disorders17/229
HypocalcemiaBlood and lymphatic system disorders15/229
NauseaGastrointestinal disorders14/229
VomitingGastrointestinal disorders13/229
Pain, abdominalGastrointestinal disorders11/229

Baseline characteristics

Age, Categorical
Age, Categorical(Participants)TDF-FTC as PrEP
<=18 years0
Between 18 and 65 years229
>=65 years0
Age, Continuous
Age, Continuous(years)TDF-FTC as PrEP
Median30 (28 to 33)
Sex: Female, Male
Sex: Female, Male(Participants)TDF-FTC as PrEP
Female102
Male127
Race/Ethnicity, Customized
Race/Ethnicity, Customized(Participants)TDF-FTC as PrEP
Black229
Region of Enrollment
Region of Enrollment(participants)TDF-FTC as PrEP
Botswana229
Enrollment Site
Enrollment Site(Participants)TDF-FTC as PrEP
Gaborone132
Francistown97
Education Level
Education Level(Participants)TDF-FTC as PrEP
Primary or less4
Secondary141
Post-secondary84
Marital Status
Marital Status(Participants)TDF-FTC as PrEP
Single163
Married18
Cohabitating37
Separated/Widowed11

4 further baseline measures are reported on the registry.

08

Study locations

No study locations are listed for this record.

09

References and documents

Individual participant data

Plan to share: No — Data cannot be shared publicly without permission from the country of Botswana but may be available upon request.

No publications or documents are linked to this record.

10

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on May 13, 2022, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
11

Registry details

Key details

Study ID
NCT04318210
Lead sponsor
Centers for Disease Control and Prevention
Collaborators
Botswana Ministry of Health
Responsible party
Sponsor
First posted
Mar 23, 2020
Start date
Oct 2012
Primary completion
Jul 2014
Completion
Jul 2014
Results posted
May 13, 2022
Last update
May 13, 2022

Study contacts

Allan Taylor, MD, MPH
principal investigator · Centers for Disease Control and Prevention

Oversight

Data monitoring committee
No
View the source record on ClinicalTrials.gov ↗

Not currently enrolling

This study is completed, as verified in May 2022. You cannot join it, but the record below documents what was studied.

Follow this study

Get an email when the registry record changes — status, dates, results — or when someone posts here.

Sign in to follow

Discussion

Questions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.

Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.

Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.

Start the discussion