Evaluation of a novel drug depletion device for removal of biological drugs from human serum

Abstract: Biological drugs such as tumor necrosis factor (TNFα) blockers are very successful and effective in therapy of chronic inflammatory disease. These blockers bind TNFα and inhibit its pro-inflammatory function. But unfortunately, biological drugs are immunogenic and prolonged treatment triggers the formation of anti-drug antibodies and neutralizing antibodies (NAbs). This reaction is associated with reduced clinical response and adverse effects. Therefore, it is of interest to detect the neutralization early during drug development and therapy. The iLite cell based assays has low tolerance for residual drug. NAbs can only be detected if they are higher in quantity than the drug. This means the assay underestimates the NAb concentration. Removing the drug specifically from the sample and release the NAbs from the complex would allow an earlier detection. In this project, newly developed gold nanoparticles coated with TNFα were tested as a drug depletion device. The nanoparticles were evaluated for their effectiveness in removing the biological drug infliximab (a TNFα-blocker) from a phosphate buffer model solution. Subsequently, the iLite cell based reporter gene assay was used for infliximab quantification or neutralizing antibody determination. Initial incompatibilities of the gold nanoparticles solution and the cell based assay were encountered, as the nanoparticle buffer solution distorted the assay signal. Consequently, the nanoparticles were optimized and the first step in depleting a simple model infliximab solution was successful. No infliximab was detectable after depletion. A subsequent depletion of infliximab from an infliximab-NAb complex model solution succeeded as well, but has potential to be improved. Future experiments have to be performed on infliximab-NAb complex spiked serum, on actual patient samples and for other TNFα-blockers.