A Novel Neutralization Antibody Assay Method to Overcome Drug Interference with Better Compatibility with Acid-Sensitive Neutralizing Antibodies.

Immunogenicity testing to detect and characterize anti-drug antibody (ADA) is required for almost all biotherapeutics. Monoclonal antibody biotherapeutics usually have long half-lives and for high-dose indications such as oncology, high level of drug will be present in the testing samples and interfere with ADA and/or neutralization antibody (NAb) measurement. To overcome this drug interference, acid-dissociation-based sample pre-treatment such as Bead-Extraction and Acid Dissociation (BEAD) has been successfully applied. The main concern for these acid-dissociation-based methods, however, is that harsh acid treatment could denature positive control Abs as well as NAb species in testing samples. In addition, high amount of biotinylated drug is needed in order to have effective competition with high level of drug in the samples, which in turn requires expensive magnetic beads. And the whole process of magnetic beads handling is tedious if doing manually and often causes trouble during assay transfer. Here, we describe a novel method which we named as Precipitation, Acid Dissociation and Biotin-drug as Assay Drug (PABAD). This novel method will need only one step of acid dissociation, with much milder and shorter acid treatment to maximally preserve NAb activity. In addition, only a fraction of biotinylated-drug is needed and there is no need to use additional streptavidin (SA)-plate or SA-magnetic beads for extraction. Compared to a BEAD-based assay, PABAD demonstrates significantly improved recovery of acid-sensitive NAb positive controls (PCs) and similar recovery of acid-resistant NAb PCs.

Water-soluble and biocompatible sono/photosensitizer nanoparticles for enhanced cancer therapy.

AIMS: Most sono/photosensitizers of cancer sonodynamic/photodynamic therapy (SDT/PDT), such as hypocrellin SL052, are water-insoluble, therefore restricting their clinical applications. In this article, we present a water-soluble nanocarrier to load the SDT/PDT sensitizer SL052 with improved pharmacokinetics and therapeutic efficacy. MATERIALS & METHODS: Nanoclusters of polyvinylpyrrolidones with SL052 formed water-soluble nanoparticles (SL052-NPs) while retaining the chemical structure of SL052. RESULTS: The experimental results show that SL052-NPs improve the drug's physicochemical properties and significantly enhance the efficacy of SL052 in terms of pharmacokinetics and cancer killing. Water-soluble SL052-NPs can be used to deliver the drug to deep cancer tissues. A potential benefit of SL052-NPs is that polyvinylpyrrolidones can help SL052 evade the reticuloendothelial system, thereby increasing circulation half-life and improving drug biodistribution. CONCLUSION: SL052-NPs greatly improved the physicochemical properties of SL052 without modifying its chemical structure, allowing for deep-site cancer drug delivery, imaging for diagnosis, and ultrasound or photocontrolled localized cancer therapy.