Emtricitabine-Triphosphate in Dried Blood Spots as a Marker of Recent Dosing

摘要: New objective measures of antiretroviral adherence are needed. We determined if emtricitabine triphosphate (FTC-TP) in dried blood spots (DBS) can be used as a marker recent dosing with tenofovir disoproxil fumarate-emtricitabine (TDF-FTC). The half-life FTC-TP was estimated DBS samples obtained from an intensive pharmacokinetic (PK) study coformulated TDF-FTC HIV-negative and HIV-infected participants. concordance quantifiable (TFV)/FTC plasma evaluated by utilizing paired plasma-DBS participants enrolled 2 large preexposure prophylaxis (PrEP) open-label trials. time to nondetectability after directly observed therapy variable TDF-FTC. mean (95% confidence interval [CI]) terminal the PK 35 (23 47) h. A total 143/163 (88%) 0 48 h post-TDF-FTC dose had DBS, compared 2/93 (2%) 0/87 (0%) >48 >96 postdose. In 746 445 PrEP trials, when both TFV/FTC were below limit quantification, well 98.9% samples, either TFV or FTC quantifiable, 90.5% samples. is short relative that TFV-diphosphate (TFV-DP), making it surrogate for TFV-FTC detection plasma. quantified simultaneously TFV-DP, which quantifies cumulative (The clinical trials discussed this article have been registered at ClinicalTrials.gov under identifiers {"type":"clinical-trial","attrs":{"text":"NCT01040091","term_id":"NCT01040091"}}NCT01040091, {"type":"clinical-trial","attrs":{"text":"NCT02022657","term_id":"NCT02022657"}}NCT02022657, {"type":"clinical-trial","attrs":{"text":"NCT00458393","term_id":"NCT00458393"}}NCT00458393, {"type":"clinical-trial","attrs":{"text":"NCT01772823","term_id":"NCT01772823"}}NCT01772823, {"type":"clinical-trial","attrs":{"text":"NCT02012621","term_id":"NCT02012621"}}NCT02012621.)