Lateral Flow Assay for Tenofovir Diphosphate Detection

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Solution Overview

Problem

Current methods for monitoring pre-exposure prophylaxis (PrEP) adherence are invasive, time-consuming, and do not provide timely or accurate results, making it difficult to assess adherence effectively in clinical settings.

Innovation Solution

Development of new antibodies against tenofovir derivatives for use in lateral flow immunodiagnostic assays to detect tenofovir diphosphate in patient samples, allowing for non-invasive, rapid, and quantitative assessment of PrEP adherence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If plasma, dried blood spot, or hair analysis tests are used to monitor PrEP adherence, then adherence information can be obtained, but the collection procedures are invasive and may not be acceptable to patients

Engineering Contradiction:

Improveadherence information accuracyVSAvoidpatient acceptance

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent extracts the measurement target from invasive biological matrices (plasma, dried blood spots, hair) to non-invasive urine samples. This extraction allows adherence monitoring without requiring blood draws or hair plucking, thereby maintaining measurement precision while dramatically improving patient acceptance and ease of sample collection

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces urine as an intermediary matrix that correlates with tenofovir adherence but is non-invasive to collect. Urine serves as a mediator between the need for accurate pharmacokinetic monitoring and patient comfort, allowing indirect but reliable adherence assessment without direct blood or tissue sampling

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If plasma, dried blood spot, or hair analysis tests are used to monitor PrEP adherence, then adherence information can be obtained, but there are delays in reporting that prevent implementation of timely interventions

Engineering Contradiction:

Improveadherence information accuracyVSAvoidreporting delay

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent employs a point-of-care lateral flow assay that provides immediate visual results at the time of sample collection, eliminating the need for centralized laboratory processing. This preliminary action delivers adherence information contemporaneously, enabling real-time clinical decision-making and immediate intervention when non-adherence is detected

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The lateral flow assay is designed to be self-contained and self-reading, requiring no external laboratory equipment or personnel for result interpretation. The test strip automatically generates visible results that can be interpreted by the patient or provider immediately, eliminating delays associated with sample transport, laboratory processing, and result reporting

Inventive Principle:

Principle #25Self-service

3Ease of operation

If self-reported adherence and pharmacy refill data are used, then adherence assessment is simple, but these methods do not correlate well with actual PrEP adherence

Engineering Contradiction:

Improveadherence assessment simplicityVSAvoidadherence accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent replaces subjective self-reporting mechanisms with objective biochemical detection. Instead of relying on patient memory or honesty, the lateral flow assay directly detects tenofovir metabolites in urine, substituting mechanical/questionnaire-based assessment with instrument-based pharmacokinetic measurement that provides accurate adherence data while remaining simple to perform

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables point-of-care testing for PrEP adherence, providing contemporaneous feedback to improve adherence and differentiate between non-adherence and resistance, while ensuring the authenticity of tenofovir in the system.

Implementation Method 1

contacting the fluid sample with a phosphatase to convert tenofovir diphosphate in the fluid sample, if present in the fluid sample, to tenofovir

Methodology Applied

Scientific EffectEnzyme catalysis: Enzyme

Implementation Method 2

allowing the labeled first reagent to bind tenofovir, if present in the fluid sample, to form a labeled first reagent-tenofovir complex

Methodology Applied

Scientific EffectAntibody-antigen binding:

Implementation Method 3

allowing the fluid sample to flow laterally along the sample pad to a conjugated label pad that is in fluid communication with the sample pad

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Data Source

PatentUS20240133877A1Products and methods for monitoring adherence to nucleoside reverse transcriptase inhibitor therapy

Publication Date: 2024.04.25 ORASURE TECHNOLOGIES INC

AI summary

The invention provides novel compounds, reagents, systems, and methods for detecting a metabolite related to a NRTI in a biological sample and use thereof in monitoring adherence to pre-exposure prophylaxis or anti-retroviral treatment. Such reagents comprise NRTI derivatives, analogs, NRTI derivatives conjugates, along with antibodies directed to same, which are useful for antibody-based methods, such as a lateral flow immunoassay and other point of care devices.