Abstract 2962: Development of the LCMS bioanalysis for clinical pharmacokinetics of antibody drugs using Fab-selective limited proteolysis (nSMOL)
Authors: Shimada Takashi , Iwamoto Noriko , Saeki Sho , Sasaki Ji-ichiro , Sato Taka-Aki , Hamada Akinobu 
Published: July 2016

Abstract
Monoclonal antibody drugs (mAbs) have become a major therapeutic strategy in cancer care. The approved mAbs have been about 40 items, and a lot of clinical trials have been now performing in the world. For precise cancer therapy, overall pharmacokinetic (PK) information in blood or tumor tissue will become the mainstream indicators for many clinicians. Therefore, versatile and robust analytical technologies for the direct detection of antibody will be important outcome in clinical applications. The bioanalysis of mAbs using LCMS is a significant platform for the selective quantitation or the feasibility of the multiplex assays for combination therapy. For regulated LCMS bioanalysis independent of a variety of mAbs or biological taxonomy sources, we have focused on the two features: antibody structure-indicated analysis, and complementarity-determining region (CDR)-targeting quantitation.
Using the previous LCMS bioanalysis by general proteomic method, the signature proteolytic peptides of the mAb should be quantified from the massive analyte and residual protease because immunoglobulin molecules are second major protein in plasma proteome. The excess peptides will be cause to decrease the selectivity and sensitivity. To address this issues, we have recently reported the novel method for the selective proteolysis on the Fab by limiting protease access to antibodies, which have named nano-surface and molecular-orientation limited (nSMOL) proteolysis. nSMOL chemistry is designed based on the unique features: (1) protease reaction on nanoparticle surface; (2) Fc immobilization onto the resin, such that the Fab is oriented outward to the solution; and (3) Fab-selective limited proteolysis by making use the difference of the protease nanoparticle diameter (200 nm) and the Ab resin pore size (100 nm). nSMOL has made it possible to minimize the sample complexity while the maintaining the sequence specificity in CDR.
We are now performing the bioanalytical validation for several mAbs in accordance with the Guideline on Bioanalytical Method Validation in Pharmaceutical Development. The results of validation study show that nSMOL is possible to cover the clinical dose, and more accurate and sensitive than ELISA and conventional proteomic approaches. For clinical feasibility test, we measured the plasma concentration of Bevacizumab in patients with recurrent non-small cell lung cancer according to nSMOL protocols.
nSMOL proteolysis coupled with LCMS bioanalysis is a novel method for the clinical PK independent of a variety of monoclonal antibodies, and have confirmed the clinical usability by the fully validated bioanalysis. This analytical approach will be applicable for many new mAbs and biosimilar drugs. Furthermore, the clinical trials based on LCMS may be expected to aid acceleration of the development of many biopharmaceuticals.
Citation Format: Takashi Shimada, Noriko Iwamoto, Sho Saeki, Ji-ichiro Sasaki, Taka-Aki Sato, Akinobu Hamada. Development of the LCMS bioanalysis for clinical pharmacokinetics of antibody drugs using Fab-selective limited proteolysis (nSMOL). [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2962.