Abstract 149P
Background
Immunotherapy has revolutionized the treatment of many cancers including CRC but is unfortunately limited to patients with microsatellite instable (MSI) tumors who only represent 15% of CRC cases. The continued success of immunotherapy in CRC relies on the identification of underlying resistance mechanisms and targeting them with innovative therapies. To address these challenges, we have developed a robust protocol to uniquely generate patient-derived CRC organoids (PDO) that retain tumor architecture and immune microenvironment as a functional patient sample for immunotherapy study.
Methods
To establish PDOs, 2 techniques are used: a matrigel drop method for amplification and cryopreservation of tumor stem cell-derived organoids (tPDO); an air-liquid interface method that we adapted to conserved immune cells to create immunocompetent organoids (iPDO). iPDO are established in culture for 7 days before histological comparison to primary tumors followed by treatment with experimental immunotherapies (7 -14 days). iPDO are then harvested for quantitative immunophenotyping and analysis of secreted factors. Biological and clinical data are combined for response and resistance signature analysis.
Results
The results of our ongoing prospective study include 20 samples of 150 planned inclusions including MSS, MSI, metastatic and nonmetastatic tumors. iPDO creation success rate is 90% (14/18 CRC, 4/4 mCRC) while tPDO is 100% with cryopreservation. Both iPDO and tPDO recapitulate the histological and genetic characteristics of the primary patient tumors. Immunophenotyping by spectral flow cytometry shows retention of major immune cell subsets for at least 30 days in culture that resemble the primary tumor including immunosuppressive cells. Preliminary evaluation of immunotherapy (anti-CD47 +/- Cetuximab, n=4) shows extensive immune microenvironment remodeling in response to treatment.
Conclusions
We have established a unique protocol and biorepository for CRC PDOs. Our iPDOs mimic the patient’s tumor and immune microenvironment ex vivo and provide an innovative functional tool to study MSS patients’ tumor immune microenvironment and their response to immunotherapies.
Clinical trial identification
NCT05955196; Release Date: 2023-01-09.
Legal entity responsible for the study
Institut Paoli-Calmettes.
Funding
Canceropôle Provence-Alpes-Côte d’Azur.
Disclosure
T. Miller: Financial Interests, Personal, Ownership Interest: Paradigm Shift Therapeutics. All other authors have declared no conflicts of interest.