Preclinical development of tumor-infiltrating lymphocyte therapy for metastatic colorectal cancer.

95Background: Immunotherapy has become an effective cancer therapy, particularly in the case of checkpoint blockade and adoptive T- cell therapy(ACT). ACT exploits the presence of tumor-infiltrating lymphocytes(TIL) by exponentially expanding their numbers ex vivo and re-infusing them into the patient in an autologous setting. With the effectiveness of TIL therapy already well established in multiple phase II studies in melanoma, there is a push to translate it to other cancers in need of improved therapies. Colorectal cancer (CRC) is a cancer where the presence of TIL has been strongly correlated with increased survival. Metastatic CRC (mCRC) has a poor outcome with median overall survival of less than 3 years. At present anti-PD1 therapy is only active in the small subset of mCRC patients (4%) that are MSI-high. We sought to evaluate the ability to generate and characterize TIL from patients with mCRC to provide a rationale for future TIL therapy in this disease. Methods: To assess the feasibility of u...