Studies of daily emtricitabine-tenofovir disoproxil fumarate (FTC-TDF) for HIV preexposure prophylaxis (PrEP) in men who have sex with men (MSM) modeled intracellular tenofovir-diphosphate (TFV-DP) in dried blood spots (DBS) to assess adherence and corresponding PrEP outcomes. We conducted a prospective, randomized, crossover pharmacokinetic study of TFV-DP in DBS during 33%, 67%, or 100% of daily dosing under directly observed therapy (DOT). Participants were assigned to two 12-week dosing regimens, separated by a 12-week washout. Forty-eight adults (25 women) from Denver and San Francisco were included. TFV-DP exhibited a median half-life of 17 days, reaching steady state in 8 weeks. TFV-DP was dose proportional with mean (SD) steady-state concentrations of 530 (159), 997 (267), and 1,605 (405) fmol/punch for the 33%, 67%, and 100% arms, respectively. Prior work in MSM demonstrated clinically meaningful TFV-DP thresholds of 350, 700, and 1,250 fmol/punch, which were estimated 25th percentiles for 2, 4, and 7 doses/week. In the present study, corresponding TFV-DP was within 3% of the prior estimates, and subgroups by site, race, and sex were within 14% of prior estimates, although males had 17.6% (95% confidence intervals [CIs], 6.5, 27.4%) lower TFV-DP than females. The thresholds of 350, 700, and 1,250 fmol/punch were achieved by 75% of men taking ≥1.2, 3.2, and 6 doses/week and 75% of women taking ≥0.6, 2.0, and 5.3 doses/week, indicating that lower dosing reached these thresholds for both sexes. In conclusion, TFV-DP arising from DOT was similar to previous estimates and is useful for interpreting PrEP adherence and study outcomes. (This study has been registered at ClinicalTrials.gov under identifier NCT02022657.).

TFV-DP in DBS is strongly associated with virologic suppression in PLWH on TDF-based therapy and is associated with certain participant characteristics. Further research is required to evaluate this drug adherence and exposure measure in clinical practice.

ObjectivesDetermine the safety, feasibility and initial efficacy of a multicomponent telerehabilitation programme for COVID-19 survivors.DesignPilot randomised feasibility study.SettingIn-home telerehabilitation.Participants44 participants (21 female, mean age 52 years) discharged home following hospitalisation with COVID-19 (with and without intensive care unit (ICU) stay).InterventionsParticipants were block randomised 2:1 to receive 12 individual biobehaviourally informed, app-facilitated, multicomponent telerehabilitation sessions with a licenced physical therapist (n=29) or to a control group (n=15) consisting of education on exercise and COVID-19 recovery trajectory, physical activity and vitals monitoring, and weekly check-ins with study staff. Interventions were 100% remote and occurred over 12 weeks.Primary and secondary outcome measuresThe primary outcome was feasibility, including safety and session adherence. Secondary outcomes included preliminary efficacy outcomes including tests of function and balance; patient-reported outcome measures; a cognitive assessment; and average daily step count. The 30 s chair stand test was the main secondary (efficacy) outcome.ResultsNo adverse events (AEs) occurred during testing or in telerehabilitation sessions; 38% (11/29) of the intervention group compared with 60% (9/15) of the control group experienced an AE (p=0.21), most of which were minor, over the course of the 12-week study. 27 of 29 participants (93%; 95% CI 77% to 99%) receiving the intervention attended ≥75% of sessions. Both groups demonstrated clinically meaningful improvement in secondary outcomes with no statistically significant differences between groups.ConclusionFully remote telerehabilitation was safe, feasible, had high adherence for COVID-19 recovery, and may apply to other medically complex patients including those with barriers to access care. This pilot study was designed to evaluate feasibility; further efficacy evaluation is needed.Trial registration numberNCT04663945.

BackgroundTenofovir diphosphate (TFV-DP) in dried blood spots (DBS) is associated with viral suppression in persons living with HIV (PLWH) taking tenofovir disoproxil fumarate (TDF). However, its value as a predictor of future viremia remained unknown.MethodsBlood for plasma viral load (VL) and TFV-DP in DBS were collected (up to 3 visits within 48 weeks) in PLWH on TDF. TFV-DP cut points were selected using logistic prediction models maximizing the area under the receiver operation characteristic curve, and estimated adjusted odds ratio (aOR) of future viremia (≥20 copies/mL) were compared to the highest TFV-DP category.ResultsAmong all 451 participants in the analysis, aOR of future viremia for participants with TFV-DP <800 and 800 to <1650 fmol/punch were 4.7 (95% CI, 2.6–8.7; P < .0001) and 2.1 (95% CI, 1.3–3.3; P = .002) versus ≥1650 fmol/punch, respectively. These remained significant for participants who were virologically suppressed at the time of the study visit (4.2; 95% CI, 1.5–12.0; P = .007 and 2.2; 95% CI, 1.2–4.0; P = .01).ConclusionsTFV-DP in DBS predicts future viremia in PLWH on TDF, even in those who are virologically suppressed. This highlights the utility of this biomarker to inform about adherence beyond VL.Clinical Trials Registration. NCT02012621.