Rapid, Cost-Effective Peptide/Nucleic Acid-Based Platform for Therapeutic Antibody Monitoring in Clinical Samples.

We demonstrate here a homogeneous assay, named NanoHybrid, for monoclonal antibody quantification directly in serum samples in a single-step format. NanoHybrid is composed of both synthetic peptide nucleic acids (PNAs) and nucleic acid strands conjugated to recognition elements and optical labels and is designed to allow fast fluorescence quantification of a therapeutic antibody. More specifically, we have characterized our analytical assay for the detection of trastuzumab (Herceptin), a monoclonal antibody (mAb) drug used for breast cancer treatment and for tumors overexpressing the HER2/neu protein. We show here that NanoHybrid is capable of performing fast drug quantification directly in blood serum. The results obtained with a pool of samples from breast cancer patients under trastuzumab treatment are compared with CE-IVD ELISA (enzyme-linked immunosorbent assay) showing a good agreement (Cohen's K = 0.729). Due to the modular nature of the NanoHybrid platform, this technology can be programmed to potentially detect and quantify any antibody for which a high-affinity recognition element has been characterized. We envision the application of NanoHybrid in a point-of-care (POC) drug monitoring system based on disposable kits for therapeutic drug management.