A Highly Sensitive and Specific Rapid Lateral Flow Assay for the HIV Integrase Strand Transfer Inhibitors Bictegravir, Cabotegravir, and Dolutegravir
Xierong Wei, Ae S. Youngpairoj, Richard Haaland, Chuong Dinh, Hetal K. Patel, Jose J. Perez, Kristin Brown, Thomas H. Vanderford, Jeffrey A. JohnsonBackground
Second‐generation HIV‐1 integrase strand transfer inhibitors (INSTIs)—bictegravir (BIC), cabotegravir (CAB), and dolutegravir (DTG)—are leading components of highly potent antiretroviral therapy, and CAB is also used for long‐acting chemoprevention. Rapid detection of clinically relevant INSTI concentrations could support point‐of‐care assessment and real‐time clinical decision‐making. We developed a lateral flow assay (LFA) that detects BIC, CAB, and DTG in whole blood and plasma and evaluated its performance against predefined concentration thresholds and high‐performance liquid chromatography‐tandem mass spectrometry (LC‐MS/MS).
Methods
A single LFA cassette design was developed using a monoclonal antibody to distinguish BIC, CAB, and DTG concentrations below trough, at minimal‐to‐moderate trough, and at ideal concentrations. LFA results were read visually at 20 min and were compared with LC‐MS/MS–quantified INSTI concentrations for 124 clinical plasma specimens.
Results
For 24 plasma samples from US participants receiving treatment involving one of the three INSTIs, the LFA interpretations matched all LC‐MS/MS results except for one DTG specimen, which was interpreted by LFA as 1.0–1.6 μg/mL but measured 2.1 μg/mL by LC‐MS/MS. Among 100 plasma remnants from routine national surveillance in Eswatini, the LFA correctly interpreted DTG concentrations in 95 specimens. Four specimens had DTG LC‐MS/MS concentrations slightly above the LFA‐determined range, differing by ≤ 0.1 μg/mL, and one specimen measured at 1.20 μg/mL by LC‐MS/MS was interpreted as ≥ 1.6 μg/mL by LFA. In total, 6 of 124 specimens (4.8%) had LFA‐interpreted INSTI concentrations that varied slightly from the LC‐MS/MS results, with no statistically significant difference in overall performance by Wilcoxon signed‐rank test ( W = 8.00, p = 0.94, one‐tailed).
Conclusions
The LFA design successfully provided clinically useful interpretations of BIC, CAB, and DTG concentrations with minor discrepancies in < 5% of samples. Importantly, all low‐concentration samples of < 1 μg/mL were correctly interpreted by LFA. The assay shows promise as a point‐of‐care tool for assessing clinically relevant INSTI concentrations.