The PUMA (Point-of-Care Urine Monitoring of Adherence) study is an open-label, 12-month, randomized controlled trial in healthy adult women receiving oral PrEP (TDF/FTC). The women receiving PrEP will be randomized (1:1) to the standard of care (n=50) versus POC urine assay testing (n=50) performed with real-time adherence feedback. Figure 2 describes the study design and the randomization process. Upon randomization, study visits will occur at 3, 6, 9, and 12 months after PrEP initiation.

The study was filed for ethical approval with the Kenya Medical Research Institute Center for Clinical Research Scientific Committee Meeting (KEMRI/SERU/CCR/0123) and the University of California, San Francisco, Institutional Review Board. All participants will be screened for eligibility and asked to provide written informed consent before study participation. Patients can withdraw from the study at any time or will be withdrawn if HIV antibody testing is positive or if incident HIV infection is detected.

A total of 100 women will be recruited, with 50 randomized to the intervention arm and 50 to the standard of care arm (Figure 2). Eligible participants will be women who are HIV-negative, not in a serodiscordant relationship, have an estimated creatinine clearance >60 mL/min, are ≥18 years old, are receiving PrEP, and are returning for a follow-up visit three months after PrEP initiation (which is the second follow-up visit under Kenyan guidelines, with the first occurring at one month after initiation) [28]. We anticipate that randomizing women at their second PrEP follow-up visit, which occurs at three months after PrEP initiation, will help minimize attrition during the study. All people must be able and willing to provide informed consent to participate in the study.

The clinical study is being conducted at the Thika Clinic, which is located in an urban center about 40 kilometers outside of Nairobi, Kenya. The clinic is a center of excellence for PrEP delivery in Kenya.

The Thika Clinic has established local recruitment and screening methods that operationalize protocol-specified requirements for eligibility determination in a manner that is tailored to and most efficient for the local setting and target population. Recruitment strategies will include partnering with existing voluntary counseling and testing centers, outreach workers, community organizations (eg, churches), and community mobilization around women’s voluntary counseling and testing promotion. Recruitment materials will educate women about PrEP. Screening and enrollment may occur on the same day or may be split across days, depending on the preference of the potential participant.

A member of the study team will approach individuals receiving PrEP. They will describe the study and ask for voluntary participation. Under the 2016 Kenya PrEP guidelines, all people initiating PrEP undergo a clinical assessment to ask about symptoms of acute HIV infection and receive rapid HIV and creatinine testing. Those who want to participate voluntarily will be taken to a private area of the clinic to be asked several demographic and clinical questions.

After obtaining written informed consent, participants will be randomized (1:1) to receive either POC urine TFV testing with same-day counseling or standard-of-care self-reported adherence monitoring (Figure 2). The study statistician will generate an allocation sequence with random numbers using SAS 9.4 (SAS Institute Inc, Cary, North Carolina, United States). Sequentially numbered, sealed, opaque envelopes containing a study arm allocation and participant identification number will be opened once an eligible, consenting participant is enrolled.

The study will follow all aspects of Kenya’s PrEP guidelines [28] except that those randomized to the intervention arm will receive POC adherence testing by a urine TFV assay (Figure 3). Once written consent is obtained, a member of the study team will collect demographic and health questions related to age, birthdate, income, employment history, prior HIV testing, medical conditions, and current symptoms. They will also obtain each participant’s phone number, address, and relevant contact information. After obtaining baseline demographic and clinical data, the study group assignment of the participant will be determined by a random process. A research nurse will then meet the participant in the same clinical exam room and administer a brief clinical questionnaire. The nurse will coordinate the necessary blood draws for the participant so that each participant will only have one blood draw for each clinical visit.

People who qualify for and initiate PrEP in Kenya according to the 2016 Kenyan PrEP guidelines [28] are subsequently seen in one month, in three months, and then every three months for repeat HIV testing. Patients on PrEP undergo continued risk assessment and adherence counseling for daily PrEP under the standard of care. PrEP delivery includes measurement of renal function (estimated creatinine clearance >60 mL/min to start PrEP and periodic monitoring over time, aligned to the visit schedule of the study), standard clinical assessment to avoid the continuation of PrEP during acute HIV infection, and adherence counseling. Participants in both arms will be counseled on PrEP and provided with three months of PrEP medication after the one-month visit, according to Kenyan national guidelines.

At study baseline and months 3, 6, 9, and 12 after enrollment, the study team will collect urine, plasma, whole blood from dried blood spots, and hair samples. Table 1 provides a summary of clinical visits and testing in both study arms. At each study visit, we will offer counseling for participants for HIV testing (pre- and posttesting), HIV infection risk reduction best practices, condom promotion and provision, adherence to PrEP medication, as well as other HIV prevention strategies. Participants in the standard-of-care arm will be directed to the regular clinical waiting area to be seen and evaluated by the study team every three months until study end (Month 12). The study team will prescribe PrEP and additional medications, as well as provide adherence counseling, as appropriate. Kenyan guidelines recommend conducting rapid testing for HIV before dispensing PrEP at each visit. If any participants have a positive rapid test by an oral or blood-based test, confirmatory testing will then be performed, and participants will receive standard HIV care, including initiation of antiretroviral therapy. All participants will receive HIV counseling, condoms, risk reduction counseling, and syndromic management of sexually transmitted infections according to local guidelines.

Participants in the intervention arm will receive the same treatment as participants in the standard-of-care arm, and also quarterly testing for TFV by a rapid urine diagnostic test. The results of the test will be provided to the participant and will be used to inform enhanced adherence counseling for those who do not demonstrate adequate PrEP adherence. An image of the POC urine adherence assay is shown in Figure 4.

Subsequently, clinic-based POC testing for urine TFV will occur at quarterly visits during the 12-month study period. Counseling messages to the women in the intervention arm will be delivered by the study team, which includes staff with extensive experience in counseling and behavioral interventions. The messages to provide feedback on adherence will be adapted from the HPTN082 (HIV Prevention Trials Network 082) study and other studies that have provided PrEP pharmacologic feedback [29]. The counseling messages for this trial will first be piloted in a small group of women on PrEP at Thika for refinement before actual implementation.

Participants enrolled in this study will be followed for a total of 12-months from the date of enrollment. The three primary outcomes for this study will be: (1) feasibility of the intervention; (2) acceptability of POC urine tenofovir testing among women receiving PrEP; and (3) preliminary impact on adherence as assessed by a long-term metric of adherence (eg, hair levels).

This study was funded by the National Institutes of Health in September 2018 (R01AI143340) and approved by the Kenya Medical Research Institute Institutional Review Board in August 2019. The study is projected to start in June 2020, with data collection from June 2020 to January 2022, data analysis commencing January 2022, and publication expected by June 2022.

A point-of-care test to analyze tenofovir concentrations in urine has recently been developed, and this protocol paper describes the design of the first pilot clinical trial incorporating POC adherence testing and feedback for participants on PrEP. Given the critical contribution of adherence to the preventative efficacy of PrEP, novel interventions to improve long-term PrEP adherence will bolster the ability of this powerful preventative strategy to stem the tide of the HIV pandemic. Self-reported adherence to PrEP is limited by social desirability bias, and no surrogate of PrEP adherence (such as HIV viral loads in those living with HIV) exists. The field has, therefore, increasingly relied on pharmacologic metrics to objectively verify PrEP adherence, but the current methods to measure drug levels are expensive and laboratory-based. The development of a novel antibody-based POC test to monitor PrEP adherence in real-time could be transformative in how we document and intervene against poor PrEP adherence, but this trial will test that concept for the first time.

Prior studies have revealed that real-time monitoring and feedback on adherence could be motivating. In the VOICE study, a placebo-controlled randomized trial testing PrEP in African women, at least 50% of women on the active drug had undetectable TFV in all plasma tested. However, participants over-reported adherence, even at the last study visit where accurate reporting would not affect study participation [5]. Further qualitative work to understand nonadherence in the VOICE study was performed through the Microbicides Trials Network–003D study, which recruited participants with pharmacokinetic (PK) data consistent with low (0% of plasma samples having detectable TFV), inconsistent, or high adherence for retrospective disclosure of plasma TFV results and subsequent capture of reactions [21]. Women with low adherence first expressed surprise at the PK results, then acknowledged they were true and revealed reasons for non-drug-taking during in-depth interviews. Women in all three categories stated that real-time monitoring and feedback would improve adherence and that they would be more honest if presented with objective adherence metrics.

In the iPrEx (Iniciativa Profilaxis Pre-Exposición) open-label extension (OLE) study, a demonstration project of PrEP among men-who-have-sex-with-men and transgender women, drug level testing was performed in plasma and dried blood spots [22]. The results of plasma drug levels over prior weeks were shared with individuals at a later visit, which was reported as highly acceptable [23]. Those with detectable drug in their plasma appreciated receiving validation of adherence, and those without drug detection were not surprised. An in-depth qualitative analysis from iPrEx OLE confirmed the acceptability of drug level feedback and, for those who were not adherent, the motivating effect of receiving such feedback on subsequent adherence. The results of these interviews led authors to conclude that: (1) drug level feedback should be provided as quickly as possible, so new methods should be sought to provide rapid feedback; and (2) drug level feedback will encourage frank adherence discussion and should be provided in the context of adherence counseling.

Urine is a suitable matrix for POC testing for PrEP adherence since urine collection is noninvasive, preferred among youth over blood sampling, and TFV levels in urine correlate with TDF adherence [34-36]. Urine levels reflect plasma levels, which may be particularly useful when daily PrEP adherence is necessary [37]. Plasma and urine PrEP drug levels reflect only short-term exposure, and thus monitoring via these matrices may be susceptible to “white coat adherence,” where adherence improves transiently before a visit. Despite this theoretical concern, this phenomenon has rarely been observed in PrEP delivery [31].

At the study’s end, we will have conducted a field test of a novel immunoassay to quantitate TFV in urine as the first POC low-cost adherence metric available for participants on PrEP. The assay will launch a novel modality for adherence intervention. Moreover, the assay could be combined with digital technologies to support PrEP adherence, which are of burgeoning interest in the PrEP adherence intervention field [38,39], especially among youth [40]. Finally, the study findings will inform a larger-scale PrEP trial assessing the impact of real-time adherence monitoring/feedback via the assay. We expect this new TFV POC assay, the metabolite of both TDF and tenofovir alafenamide, to have widespread utility in both HIV prevention and treatment globally. The pilot trial proposed here will examine the acceptability, feasibility, and impact of this novel TFV adherence assay in urine for the first time. Improving adherence to both PrEP and ART will help reduce and prevent HIV transmission in the efforts to end the HIV/AIDS epidemic.