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Objectives: We measured the intracellular concentrations of tenofovir-diphosphate (TFV-DP) and emtricitabine-triphosphate (FTC-TP) in dried blood spots (DBS) for pre-exposure prophylaxis (PrEP) adherence using sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS)., Methods: A total of 191 DBS were obtained from 85 participants who were receiving tenofovir disoproxil fumarate (TDF; 300 mg) and emtricitabine (FTC; 200 mg) as PrEP at the Sexual Health Clinic, National Center for Global Health and Medicine, Tokyo, Japan. DBS punch (3 mm) added to 25 μL of 50% methanol and 400 μL of internal standard solution was used for solid phase extraction. Chromatographic separation was achieved on an Atlantis Premier BEH C18 AX Column (50 mm × 2.1 mm i.d.; particle size 1.7 μm) using gradient elution (flow rate: 0.6 mL/min); injection volume: 7 μL and run time: 5.5 min. Calibration curves for the two drugs were linear in the range 0.05-12.5 ng/punch., Results: We determined the intracellular TFV-DP and FTC-TP concentrations in 191 DBS obtained from 85 patients administered with TDF and FTC as PrEP. The analytical performance data (calibration curve and QC samples) for all the analytical runs met the acceptance criteria. Intracellular concentrations of TFV-DP and FTC-TP in the DBS remained stable for at least 24 h after oral administration., Conclusions: A multiplex LC-MS/MS method was successfully developed for DBS, which can be useful for monitoring the levels of TFV-DP and FTC-TP in individuals receiving PrEP., (Copyright © 2024 Japanese Society of Chemotherapy, Japanese Association for Infectious Diseases, and Japanese Society for Infection Prevention and Control. Published by Elsevier Ltd. All rights reserved.)

Background and Aims: Men who have sex with men (MSM) are vulnerable to contracting HBV as a sexually transmitted infection. We evaluated the incidence of HBV infection (HBI) and the prophylactic effect of tenofovir-based pre-exposure prophylaxis (PrEP) on HBI in an MSM cohort., Methods and Results: MSM who were older than 16 years were enrolled from January 2018 and followed up until June 2021 and tested for HIV, bacterial sexually transmitted infections, and HBsAg/ HBsAb and HBcAb every 3 months based on inclusion criteria, including HBsAg, HBcAb, HBsAb, and HIV negativity at enrollment. HBI was defined as seroconversion of HBsAg or HBcAb status. The log-rank test was used to evaluate the prophylactic effect of PrEP against HBI. As a substudy, individuals excluded from the main study due to HBs Ab positivity were evaluated for HBI incidence. Among 1577 MSM, 786 participants (546 PrEP nonusers, 131 daily PrEP users, and 109 event-driven PrEP users) met the criteria and were included. The annual incidence of HBV among PrEP nonusers (3.8%, 21 infections, with 559.5 person-years) was significantly higher ( p = 0.018, log-rank test) than that among daily PrEP users [0.77%, 1 infection (admitted nonadherence), with 129.3 person-years] and event-driven PrEP users (no infection with 93.8 person-years). Although the incidence of HBI and HIV infection decreased with PrEP use, the incidence of other sexually transmitted infections was higher in both daily and event-driven PrEP users. The annual incidence of HBV among HBsAb-positive and HBcAb-negative PrEP nonusers was 1.8% (3 infections, with 167.5 person-years)., Conclusions: Tenofovir-based PrEP prevented HBI among MSM in a real-world setting., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc.)

Background: While global efforts have been made to prevent transmission of HIV, the epidemic persists. Men who have sex with men (MSM) are at high risk of infection. Despite evidence of its cost-effectiveness in other jurisdictions, pre-exposure prophylaxis (PrEP) for MSM is neither approved nor reimbursed in Japan., Method: The cost-effectiveness analysis compared the use of once daily PrEP versus no PrEP among MSM over a 30-year time horizon from a national healthcare perspective. Epidemiological estimates for each of the 47 prefectures informed the model. Costs included HIV/AIDS treatment, HIV and testing for sexually transmitted infections, monitoring tests and consults, and hospitalization costs. Analyses included health and cost outcomes, as well as the incremental cost-effectiveness ratio (ICER) reported as the cost per quality-adjusted life year (QALY) for all of Japan and each prefecture. Sensitivity analyses were performed., Findings: The estimated proportion of HIV infections prevented with the use of PrEP ranged from 48% to 69% across Japan, over the time horizon. Cost savings due to lower monitoring costs and general medical costs were observed. Assuming 100% coverage, for Japan overall, daily use of PrEP costs less and was more effective; daily use of PrEP was cost-effective at a willingness to pay threshold of ¥5,000,000 per QALY in 32 of the 47 prefectures. Sensitivity analyses found that the ICER was most sensitive to the cost of PrEP., Interpretation: Compared to no PrEP use, once daily PrEP is a cost-effective strategy in Japanese MSM, reducing the clinical and economic burden associated with HIV.

Background: Pre-exposure prophylaxis (PrEP) with tenofovir/emtricitabine (TDF/FTC) has been recommended worldwide. We evaluated the safety and efficacy of daily PrEP with TDF/FTC in Tokyo., Methods: This single-center, single-arm study was performed with 124 men who have sex with men (MSM) between January 2017 and March 2021. MSM who entered into an MSM cohort from January 2017 through March 2018 and had a pre-PrEP observational period of 1 year were eligible and recruited to the study between April 2018 and March 2019 and followed for 2 years. The primary outcome was the incidence of HIV infection (per 100 person-years). Secondary outcomes were the incidence of sexually transmitted infections and adverse events, and the rate of retention and adherence to PrEP., Results: There were 309 MSM registered in the cohort (mean age, 36.6 years); 124 fulfilled the criteria and were included in the study. The remaining patients were continuously followed. There was a significant decrease in incidental HIV infection among PrEP users (0 infections, 235.5 person-years) compared to non-PrEP users (11 infections [3.4%/year], 318.9 person-years; p = 0.01). The average adherence rate was consistently greater than 95%, and the retention rate at two years was approximately 80%., Conclusions: The present study showed a high prophylactic effect against HIV infection, retention, and adherence to PrEP. PrEP is feasible and highly recommended in Japan., Trial Registration: UMIN Clinical Trials Registry (UMIN000031040, www.umin.ac.jp), Japan Registry of Clinical Trials (jRCTs031180134)., (Copyright © 2022 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)