Drug‐Tolerant, Chemiluminescent Lateral Flow Immunoassay Platform for the Determination of Neutralizing Anti‐Drug Antibodies

Abstract Administration of mAb therapeutics often elicits the production of neutralizing anti‐drug antibodies (nADA) in patients. Current nADA assays are drug‐sensitive and detect only free nADA, thereby overlooking drug‐bound antibodies and reducing sensitivity. An extra preparatory step of acid dissociation is often applied to resolve the immunocomplexes and subsequently detect the resultant free nADA separately. This tedious sample preparation limits them to lab settings and exposes the antibodies to harsh conditions. Here, a modified lateral flow assay platform, namely sequential binding flow immunoassay (SBFIA) is presented for nADA determination that circumvents the drug's interference through a distinctive approach. Drawing inspiration from chromatography, sequential binding events (competitive and direct) are exploited to eliminate drugs’ interference, enabling sensitive detection of drug‐bound nADA. The platform is optimized using Infliximab (IFX) as a drug and neutralizing anti‐Infliximab antibodies (nαIFX) as a model analyte. After optimization, a minimum concentration of 103 ng mL ⁻¹ nαIFX is detected. The assay shows remarkable drug tolerance and specificity to nαIFX. Based on its point‐of‐care (POC) advantages while avoiding harsh, acidic sample pretreatment, the assay can assist physicians in rapid and accurate decision‐making. By tweaking the bioreceptors, the configuration can adapt well to other biologics and respective nADA.