Immunotherapy with lymphocytes derived from banked tumor tissue in two refractory NSCLC patients with leptomeningeal metastases: a report of two cases.

Background: Cancer patients relapsing with leptomeningeal metastases (LM) but without extracranial lesions are usually unsuitable for cellular immunotherapy with tumor-infiltrating lymphocytes (TILs) owing to lack of tumor tissue. TILs generated from heavily pretreated patients, especially those with non-melanoma cancer often have anergic effects and are less toxic to tumors, limiting the antitumor efficacy of lymphocyte-based therapy. Whether using autologous tumor tissue banked in advance addresses the dilemma has not been explored. Case Description: We present two cases of non-small cell lung cancer (NSCLC) who relapsed with LM but without extracranial lesions for whom TIL therapy is otherwise unsuitable. Using autologous tumor tissue banked in advance when they initially underwent tumor resection, we successfully generated therapeutic TILs of which the enhancer of zeste homolog 2 (EZH2) activity was further inhibited in regulatory T cells (Tregs). One case received autologous TILs prepared from a cryopreserved pathological complete response lesion and achieved a complete remission of LM that was ongoing till the preparation of this manuscript. The other case was treated with autologous TILs derived from a cryopreserved treatment-naïve tumor tissue and only achieved a transient response manifested by short-term decrease of circulating tumor deoxyribonucleic acid and serum carcinoembryonic antigen. Conclusions: TILs generated from treatment-responsive lesions and underwent inhibition of EZH2 activity in Tregs have high antitumor efficacy and the banking in advance of treatment-responsive tumor tissue potentially provides a safe and effective adoptive cell therapy (ACT) with TILs for refractory NSCLC patients with LM for whom TIL therapy is otherwise unsuitable.