Development and validation of an assay to analyze atazanavir in human hair via liquid chromatography/tandem mass spectrometry

Simultaneous Determination of 6 Antiretroviral Drugs in Human Hair Using an LC-ESI+-MS/MS Method: Application to Adherence Assessment

BACKGROUND

The determination of antiretroviral drugs in hair is receiving considerable research interest to assess long-term adherence to antiretroviral therapy (ART). Currently in China, lamivudine, zidovudine, nevirapine, efavirenz, ritonavir, and lopinavir are combined as first-line and second-line free therapy regimens and are recommended for people living with HIV (PLWH). Simultaneous determination of the 6 antiretroviral drugs in human hair is important for accurately and widely assessing long-term adherence in Chinese PLWH receiving different ART regimens.

METHODS

Six drugs were extracted from 10-mg hair samples incubated in methanol for 16 hours at 37°C and then analyzed by liquid chromatography with tandem mass spectrometry using a mobile phase of 95% methanol, with an electrospray ionization source in multiple reaction monitoring and positive mode.

RESULTS

The LC-ESI+-MS/MS method exhibited a linear range (R2 > 0.99) within 6-5000, 10-5000, 6-50,000, 12-50,000, 8-5000, and 8-12,500 pg/mg for lamivudine, zidovudine, nevirapine, efavirenz, ritonavir, and lopinavir. For all 6 drugs, the limits of quantification ranged between 6 and 12 pg/mg. The intraday and interday coefficients of variation were within 15%, and the recoveries ranged from 91.1% to 113.7%. Furthermore, the other validation parameters (ie, selectivity, matrix effect, stability, and carryover) met the acceptance criteria stipulated by guidelines of the US Food and Drug Administration and European Medicines Agency. Significant intergroup differences were observed between high-adherence and low-adherence groups, with high intercorrelations in the hair content of the 6 drugs.

CONCLUSIONS

The developed method demonstrated good reliability, to comprehensively and accurately assess adherence in PLWH receiving different ART regimens.

Antiretroviral hair levels, self-reported adherence, and virologic failure in second-line regimen patients in resource-limited settings

OBJECTIVE

To evaluate associations between hair antiretroviral hair concentrations as an objective, cumulative adherence metric, with self-reported adherence and virologic outcomes.

DESIGN

Analysis of cohort A of the ACTG-A5288 study. These patients in resource-limited settings were failing second-line protease inhibitor-based antiretroviral therapy (ART) but were susceptible to at least one nucleoside reverse transcriptase inhibitor (NRTI) and their protease inhibitor, and continued taking their protease inhibitor-based regimen.

METHODS

Antiretroviral hair concentrations in participants taking two NRTIs with boosted atazanavir (n = 69) or lopinavir (n = 112) were analyzed at weeks 12, 24, 36 and 48 using liquid-chromatography--tandem-mass-spectrometry assays. Participants' self-reported percentage of doses taken in the previous month; virologic failure was confirmed HIV-1 RNA at least 1000 copies/ml at week 24 or 48.

RESULTS

From 181 participants with hair samples (61% women, median age: 39 years; CD4+ cell count: 167 cells/μl; HIV-1 RNA: 18 648 copies/ml), 91 (50%) experienced virologic failure at either visit. At 24 weeks, median hair concentrations were 2.95 [interquartile range (IQR) 0.49-4.60] ng/mg for atazanavir, 2.64 (IQR 0.73--7.16) for lopinavir, and 0.44 (IQR 0.11--0.76) for ritonavir. Plasma HIV-1 RNA demonstrated inverse correlations with hair levels (rs -0.46 to -0.74) at weeks 24 and 48. Weaker associations were seen with self-reported adherence (rs -0.03 to -0.24). Decreasing hair concentrations were significantly associated with virologic failure, the hazard ratio (95% CI) for ATV, LPV, and RTV were 0.69 (0.56-0.86), 0.77 (0.68-0.87), and 0.12 (0.06-0.27), respectively.

CONCLUSION

Protease inhibitor hair concentrations showed stronger associations with subsequent virologic outcomes than self-reported adherence in this cohort. Hair adherence measures could identify individuals at risk of second-line treatment failure in need of interventions.

Tenofovir and emtricitabine concentrations in hair are comparable between individuals on tenofovir disoproxil fumarate versus tenofovir alafenamide-based ART

Tenofovir disoproxil fumarate (TDF) in combination with emtricitabine (FTC) is the backbone for both human immunodeficiency virus (HIV) treatment and pre-exposure prophylaxis (PrEP) worldwide. Tenofovir alafenamide (TAF) with FTC is increasingly used in HIV treatment and was recently approved for PrEP among men-who-have-sex-with-men. TDF and TAF are both metabolized into tenofovir (TFV). Antiretrovirals in plasma are taken up into hair over time, with hair levels providing a long-term measure of adherence. Here, we report a simple, robust, highly sensitive, and validated high-performance liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS)-based analytical method for analyzing TFV and FTC from individuals on either TDF/FTC or TAF/FTC in small hair samples. TFV/FTC are extracted from ~5 mg hair and separated on a column using a gradient elution. The lower quantification limits are 0.00200 (TFV) and 0.0200 (FTC) ng/mg hair; the assay is linear up to 0.400 (TFV) and 4.00 (FTC) ng/mg hair. The intra-day and inter-day coefficients of variance (CVs) are 5.39-12.6% and 6.40-13.5% for TFV and 0.571-2.45% and 2.45-5.16% for FTC. TFV concentrations from participants on TDF/FTC-based regimens with undetectable plasma HIV RNA were 0.0525 ± 0.0295 ng/mg, whereas those from individuals on TAF/FTC-based regimens were 0.0426 ± 0.0246 ng/mg. Despite the dose of TFV in TDF being 10 times that of TAF, hair concentrations of TFV were not significantly different for those on TDF versus TAF regimens. Pharmacological enhancers (ritonavir and cobicistat) did not boost TFV concentrations in hair. In summary, we developed and validated a sensitive analytical method to analyze TFV and FTC in hair and found that hair concentrations of TFV were essentially equivalent among those on TDF and TAF.

Approaches to Objectively Measure Antiretroviral Medication Adherence and Drive Adherence Interventions

PURPOSE OF REVIEW

Traditional methods to assess antiretroviral adherence, such as self-report, pill counts, and pharmacy refill data, may be inaccurate in determining actual pill-taking to both antiretroviral therapy (ART) or pre-exposure prophylaxis (PrEP). HIV viral loads serve as surrogates of adherence on ART, but loss of virologic control may occur well after decreases in adherence and viral loads are not relevant to PrEP.

RECENT FINDINGS

Pharmacologic measures of adherence, electronic adherence monitors, and ingestible electronic pills all serve as more objective metrics of adherence, surpassing self-report in predicting outcomes. Pharmacologic metrics can identify either recent adherence or cumulative adherence. Recent dosing measures include antiretroviral levels in plasma or urine, as well as emtricitabine-triphosphate in dried blood spots (DBS) for those on tenofovir-emtricitabine-based therapy. A urine tenofovir test has recently been developed into a point-of-care test for bedside adherence monitoring. Cumulative adherence metrics assess adherence over weeks to months and include measurement of tenofovir-diphosphate in peripheral blood mononuclear cells or DBS, as well as ART levels in hair. Electronic adherence monitors and ingestible electronic pills can track pill bottle openings or medication ingestion, respectively. New and objective approaches in adherence monitoring can be used to detect nonadherence prior to loss of prevention efficacy or virologic control with PrEP or ART, respectively.

Influence of hair treatments on detection of antiretrovirals by mass spectrometry imaging

Analysis of drugs in hair by mass spectrometry imaging (MSI) has great potential as an objective, long-term measure of medication adherence. However, the fidelity of the chemical record in hair may be compromised by any cosmetic hair treatments. Here, we investigate infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) MSI response to multiple antiretrovirals (ARVs) in cosmetically treated hair. Hair strands from patients on different ARV regimens were mechanically treated with dye, bleach, and relaxer. The treatments had little or no effect relative to untreated controls for cobicistat, abacavir, dolutegravir, maraviroc, efavirenz, and darunavir, but all three treatments removed emtricitabine (FTC) to undetectable levels from patient hair strands. We also evaluated hair strands by IR-MALDESI MSI from 8 patients on FTC-based regimens who reported a range of hair treatments at varying recency prior to hair collection. While FTC was undetectable in the treated portion of these hair strands, ARVs coadministered with FTC remained detectable in hair strands after treatment. We conclude that IR-MALDESI MSI can be used when measuring adherence to ARV therapy, provided that ARVs other than FTC are targeted in people using hair treatments.

Development and validation of a UPLC-MS method for determination of atazanavir sulfate by the "analytical quality by design" approach

A UPLC-MS method for the estimation of atazanavir sulfate was developed using the "analytical quality by design" approach. The critical chromatographic quality attributes identified were retention time, theoretical plates and peak tailing. The critical method parameters established were percent of organic modifier, flow rate and injection volume. Optimization performed using Box-Behnken Design (BBD) established 10 % organic modifier, 0.4 mL min-1 flow rate and 6-µL injection volume as the optimum method conditions. Atazanavir sulfate eluted at 5.19 min without any interference. Method validation followed international guidelines. The method has proven linearity in the range of 10-90 µg mL-1. Recovery was between 100.2-101.0 % and precision within the accepted limits (RSD 0.2-0.7 %). LOD and LOQ were 2.68 and 8.14 µg mL-1, resp. Stress testing stability studies showed atazanavir sulfate to degrade under acidic and basic conditions. The suggested technique is simple, rapid and sustainable. It is, therefore, suggested for routine analysis of atazanavir sulfate.

Measuring Adherence to Antiretroviral Therapy via Hair Concentrations in India

BACKGROUND

Objective adherence measures are of increasing interest in antiretroviral treatment (ART) monitoring. Hair ART levels predict virologic suppression, and hair is easy to collect and store. No previous study has examined hair levels in an India-based cohort or laboratory.

METHODS

Small hair samples were collected from HIV-positive participants on either efavirenz (EFV)-based or nevirapine (NVP)-based ART in a South India-based study. Hair samples were split and analyzed for EFV or NVP in the University of California, San Francisco -based Hair Analytical Laboratory and the analytic laboratory of the Division of Nutrition at St. John's Research Institute, Bangalore, India, using liquid chromatography/tandem mass spectrometry. Agreement (using Bland-Altman methods) and rank correlation between the 2 laboratories' hair levels were calculated. Rank correlation between self-reported adherence (SRA) over the previous month using a visual analog scale and hair ART levels was calculated.

RESULTS

Among 75 participants (38 on NVP; 37 on EFV), the correlation between NVP levels generated by the 2 laboratories was 0.66 (P < 0.0001) and between EFV levels was 0.87 (P < 0.0001). Measurements from St. John's Research Institute were usually within 20% of those from the University of California, San Francisco Hair Analytical Laboratory. SRA was essentially uncorrelated with hair antiretroviral levels for either drug (all correlations < 0.04). Hair levels showed variability in adherence although SRA was >85% in all participants.

CONCLUSIONS

Hair ART levels measured by both an India-based laboratory and the standard U.S.-based laboratory showed generally high agreement and correlation, demonstrating local capacity. As in many other cohorts, hair ART levels and SRA were not well-correlated, likely indicating limitations in self-report and the need for objective adherence monitoring in resource-limited settings.

Infrared Matrix-Assisted Laser Desorption Electrospray Ionization Mass Spectrometry Imaging of Human Hair to Characterize Longitudinal Profiles of the Antiretroviral Maraviroc for Adherence Monitoring

Here, we assess infrared matrix assisted laser desorption electrospray ionization (IR-MALDESI) mass spectrometry imaging (MSI) analysis of hair as a clinical tool for monitoring patient adherence to the antiretroviral maraviroc (MVC). A custom MATLAB-based algorithm has been developed to streamline data analysis and generate longitudinal profiles of drug incorporation along the length of hair strands. Hair strands from volunteers enrolled in a directly observed therapy study were analyzed by IR-MALDESI MSI and processed using this tool to characterize the profiles of single doses and a daily dose regimen of MVC. Single dose responses were 1.7 [1.1, 2.5] mm (median [range]) wide along the length of the hair and were detected in 8 out of 12 volunteers. Daily dose profiles capturing 28 days of continuous dosing were approximately 5 times the intensity of single dose profiles and 10.5 [7.0, 13] mm wide, corresponding to 1 month of hair growth. MVC ion abundance was observed in all 12 volunteers for the daily dosing period. Daily dosing profiles were consistent with a model of MVC accumulation in hair based on linear superposition of a single dose response, indicating the potential for prediction of daily drug-taking behavior based on deconvolution of a complex longitudinal profile in hair.

Antiretroviral Concentrations in Hair Strongly Predict Virologic Response in a Large Human Immunodeficiency Virus Treatment-naive Clinical Trial

Concentrations of antiretrovirals in hair are associated with virologic outcomes in cohorts of human immunodeficiency virus (HIV)-positive individuals but have never been examined in a clinical trial. We show for the first time the predictive utility of hair antiretroviral concentrations in a large HIV treatment-naive trial (AIDS Clinical Trials Group protocol A5257).

Development and Validation of an Immunoassay for Tenofovir in Urine as a Real-Time Metric of Antiretroviral Adherence

BACKGROUND

Pharmacologic adherence measures were critical to the interpretation of the tenofovir (TFV)-disoproxil-fumarate/emtricitabine (TDF/FTC) PrEP trials. These measures are being incorporated into PrEP demonstration projects, but currently-available metrics in plasma, cells, hair or urine involve expensive and time-intensive mass-spectrometry (MS)-based methods. No point-of-care method to assess PrEP adherence in real-time has yet been implemented. Antibody-based tests allow for low-cost, easy-to-perform, point-of-care drug detection. In this study, we developed an antibody-based TFV immunoassay and evaluated its test characteristics among individuals taking TDF/FTC.

METHODS

We synthesized possible immunogens based on TFV's molecular structure, injected rabbits with the conjugated derivatives, and bled them monthly for subsequent ELISA-testing for TFV-specific antibodies. We purified an antibody with specific TFV binding and created dose-response curves for ELISA-quantification. We then quantified TFV in urine from human participants not taking TDF/FTC and from individuals taking daily TDF/FTC 300 mg/200 mg for 7 days with a 7-day washout period using ELISA with this TFV-specific antibody. ELISA results were compared with the gold-standard test for TFV detection/quantification using liquid-chromatography-tandem-MS (LC-MS/MS).

FINDINGS

None of the urine samples from 115 participants not taking TDF/FTC showed ELISA- reactivity, indicating 100% specificity (95% CI 97-100%) of the immunoassay. Among participants taking TDF/FTC, 67 of 70 samples positive by LC-MS/MS were positive by the ELISA-immunoassay for an estimated diagnostic sensitivity of 96% (95% CI 88-99%). The precision of the assay was high (coefficient of variationb15%). The rank correlation between ELISA and LC-MS/MS values in the 70 quantitative urine TFV levels positive by LC-MS/MS across a wide range of concentrations among participants on TDF/FTC was high (r = 0.96).

INTERPRETATION

Our antibody-based immunoassay for measuring TFV in urine performed well compared to the gold-standard of LC-MS/MS among individuals taking TDF/FTC. A sensitive and specific immunoassay paves the way for real-time monitoring/feedback on recent adherence to TFV-based regimens, which should optimize interpretation and outcomes during PrEP and ART roll-out.