Extended Analysis of HIV Infection in Cisgender Men and Transgender Women Who Have Sex with Men Receiving Injectable Cabotegravir for HIV Prevention: HPTN 083.

HPTN 083 demonstrated that injectable cabotegravir (CAB) was superior to oral tenofovir disoproxil fumarate-emtricitabine (TDF-FTC) for HIV prevention in cisgender men and transgender women who have sex with men. We previously analyzed 58 infections in the blinded phase of HPTN 083 (16 in the CAB arm and 42 in the TDF-FTC arm). This report describes 52 additional infections that occurred up to 1 year after study unblinding (18 in the CAB arm and 34 in the TDF-FTC arm). Retrospective testing included HIV testing, viral load testing, quantification of study drug concentrations, and drug resistance testing. The new CAB arm infections included 7 with CAB administration within 6 months of the first HIV-positive visit (2 with on-time injections, 3 with ≥1 delayed injection, and 2 who restarted CAB) and 11 with no recent CAB administration. Three cases had integrase strand transfer inhibitor (INSTI) resistance (2 with on-time injections and 1 who restarted CAB). Among 34 CAB infections analyzed to date, diagnosis delays and INSTI resistance were significantly more common in infections with CAB administration within 6 months of the first HIV-positive visit. This report further characterizes HIV infections in persons receiving CAB preexposure prophylaxis and helps define the impact of CAB on the detection of infection and the emergence of INSTI resistance.

Development and validation of a multiplexed assay for the measurement of long-acting hormonal contraceptives in plasma via liquid chromatography-tandem mass spectrometry.

BACKGROUND: Exogenous progestins are an effective tool for hormonal contraception and family planning. Progestins may be delivered as oral pills, intramuscular or subcutaneous injections, vaginal rings, or intrauterine devices. Drug concentrations may vary based on the route and duration of delivery. Measurement of synthetic steroids in blood plasma can aid in determination of product adherence, evaluation of drug-drug interactions, and investigation of unintended pregnancies. METHODS: Drug-free K2EDTA plasma was spiked with the synthetic steroids etonogestrel (ETO), levonorgestrel (LNG), medroxyprogesterone acetate (MPA), and norethisterone (NET). Plasma was combined with isotopically labeled internal standards, and drugs were extracted via liquid-liquid extraction. Samples were then subjected to liquid chromatographic-tandem mass spectrometric (LC-MS/MS) analysis. The method was validated in accordance with regulatory recommendations. The assay was evaluated in a cohort of remnant plasma samples in individuals using one of the aforementioned progestins. RESULTS: The analytical measuring range for ETO, MPA, and NET was 20-10,000 pg/mL; the primary linearity for LNG was 20-20,000 pg/mL. The method showed acceptable precision and accuracy for all progestins. Stability was established for 72 h with room temperature storage and through 3 freeze-thaw cycles. All analytes were stable in whole blood incubated at room temperature for 25 h, and at 40°C and 100% humidity for 2 h. Ion suppression was observed for all analytes spiked in plasma; average ion suppression was 31.6%, 66.6%, 32.1% and 41.2% for ETO, LNG, MPA, and NET, respectively. However, internal standards showed comparable ion suppression, and relative matrix effects were minimal. ETO, LNG, MPA, and NET could also be quantified accurately in K3EDTA plasma and serum. Progestins were successfully measured in remnant samples from individuals using hormonal contraceptives. CONCLUSIONS: A multiplexed LC-MS/MS assay for the quantification of ETO, LNG, MPA, and NET has been developed and validated. The assay met acceptable performance characteristics and may be used in downstream studies to evaluate progestin pharmacology.

Development and validation of a liquid chromatographic-tandem mass spectrometric assay for the quantification of cabotegravir and rilpivirine from dried blood spots.

BACKGROUND: Dried blood spots (DBS) have been utilized as a blood plasma alternative for therapeutic drug monitoring and pharmacologic analysis. There are analytical and physiochemical considerations in bridging drug concentrations from plasma to DBS. Recently, the long-acting antiretroviral cabotegravir (CAB) has been approved for HIV prevention, and a co-packaged regimen of long-acting CAB and rilpivirine (RPV) has been approved for HIV treatment. Measurement of these drugs in blood collected as DBS may offer increased capacity and flexibility in translational applications. METHODS: Whole blood was spiked with CAB and RPV and spotted on DBS cards. Following extraction and addition of isotopically labeled internal standards, samples were subjected to liquid chromatographic-tandem mass spectrometric (LC-MS/MS) analysis. The method was validated according to regulatory recommendations, and the assay was evaluated in remnant samples from an HIV prevention trial in which paired DBS and plasma samples were collected. RESULTS: DBS CAB and RPV concentrations were linear from 25 to 20,000 ng/mL and 2-2500 ng/mL, respectively. Precision, accuracy, and matrix effect results were acceptable. DBS RPV demonstrated stability under all tested conditions; DBS CAB showed mean biases of - 23.5% when stored at room temperature for 36 days, and - 18.0% at 40 °C and 100% humidity for two days. DBS measurements for CAB and RPV were an average 54.0% and 14.1% lower, respectively, as compared to paired plasma samples. Derived conversion factors of 1.79 and 1.16 were applied to DBS CAB and RPV measurements, respectively, to estimate plasma concentrations. Estimated plasma CAB and RPV concentrations showed mean biases of 2.2% and 0.6%, respectively. In a CAB clinical trial, application of the conversion factor resulted in agreement between estimated plasma CAB concentrations from DBS and plasma CAB concentrations (y = 1.08x - 79.2, r = 0.932; mean bias of -3.2%; 95% CI: -48.2% to 41.9%). CONCLUSIONS: We developed and validated a novel LC-MS/MS assay for the quantification of CAB and RPV from DBS, and identified conversion factors to estimate plasma concentrations from spotted blood.