Development of a patient-derived organotypic spheroids (PDOTS) platform for prediction of clinical responses to immuno-oncology drugs

ABSTRACT As many new immuno-oncology (IO) therapies for cancer are developed, oncologists will be faced with the challenge of choosing from hundreds of drugs with thousands of potential combinations to treat their patients. Xsphera Biosciences Inc. (XB) believes one solution to this challenge lies in a novel combination of a tumor processing method that produces patient-derived organotypic tumor spheroids (PDOTS) and a microfluidic device that preserves the tumor microenvironment of a patient’s tumor. XB aims to develop the PDOTS platform to 1) provide oncologists with data-driven treatment options for their patients and 2) provide biopharmaceutical companies with data that will de-risk IND initiation by reliably predicting patient clinical responses to IO and chemotherapeutic drugs. One of the key actions needed is a systematic evaluation and optimization of the different classes of immunotherapeutic drugs in the platform. These classes include, but are not limited to, tumor cell-targeted IgG1 antibodies (tumor-targeted Abs), checkpoint inhibitors, gene therapy, and cell therapy including chimeric antigen receptor T-cell therapy (CAR-T). This project aims to establish the parameters to test tumor-targeted Ab therapeutics in the Xsphera platform and, using cetuximab in colorectal cancer (CRC), confirm that the efficacy of cetuximab aligns with the historical clinical experience. Specific Aim 1 will characterize the effects of cetuximab on CRC PDOTS in the Xsphera platform and determine if the ex vivo responses in RAS wild type (RASwt) and RAS mutant tumors (RASmut) are consistent with those reported in the clinic. Cetuximab is indicated for RASwt but has shown no efficacy in tumors with RASmut.The immune activation in the PDOTS induced by cetuximab will be characterized, and the cytokine and gene expression profiles for immune activation and apoptosis will be measured and correlated with cytotoxicity data. Specific Aim 2 will characterize the kinetics of Ab-mediated immune activation to establish the optimal time to monitor cytotoxicity and immune activation signals. Using the dose of cetuximab that induced the highest level of cytotoxicity, the kinetics of Ab mediated cytotoxicity and immune modulation will be characterized during the first 3 days after Ab treatment. The timepoint with the highest cytotoxicity and immune modulatory signals and the lowest variability between replicates and between patients will support standardization on the timepoint for cetuximab treatment. Specific Aim 2 will further characterize the immune involvement by mAb neutralization of known immune effector mechanisms, including NK cells, CTL cells and the complement cascade. Results of Phase I will confirm whether clinically approved cetuximab is effective in the platform by quantifying cytotoxicity and characterizing immune activation and whether it aligns with historical clinical response data and for being restricted to RASwt.NARRATIVE As many new oncology therapies for cancer are developed, oncologists will be faced with the challenge of choosing from hundreds of drugs with thousands of potential combinations to treat their patients. To address this challenge, Xsphera Biosciences Inc. aims to develop a platform to reliably predict patient clinical responses to immuno-oncology, targeted, and chemotherapeutic drugs to guide treatment decisions for individual patients. In the proposed project, the Xsphera platform will be validated and optimized to enable the platform to move closer towards commercialization in clinical settings as well as in the assessment and development of preclinical experimental therapeutics.