Safety and Tolerability of Letetresgene Autoleucel (Lete-cel; GSK3377794): Pilot Studies in Patients With Advanced Non-Small Cell Lung Cancer.

Purpose: To evaluate safety, tolerability, and anti-tumor response of lete-cel, genetically modified autologous T-cells expressing a T-cell receptor specific for NY-ESO-1/LAGE-1a shared epitope, alone or in combination with pembrolizumab, in human leukocyte antigen HLA-A*02-positive (HLA-A*02:01-, HLA-A*02:05-, and/or HLA-A*02:06-) patients with New York esophageal squamous cell carcinoma 1 (NY-ESO-1)- and/or LAGE-1a-positive non-small cell lung cancer (NSCLC).

Experimental design: Study 208749 was a single-arm study of lete-cel alone. Study 208471 was a multi-arm study of lete-cel alone or in combination with pembrolizumab in patients with advanced or recurrent NSCLC.

Results: Over 2500 patients were screened for target expression. In the multi-arm study, 738 (45%) of 1638 tested patients were HLA-A*02-positive. NY-ESO-1 and LAGE-1a testing was positive in 12% (62/525) and 4% (15/348) of tested patients, respectively. Forty-one patients positive for HLA-A*02 and antigen expression were screened in the single-arm study. Overall, 43 patients underwent leukapheresis and 18 received lete-cel across studies. Lete-cel demonstrated a manageable safety profile. No fatal treatment-related serious adverse events (AEs) were reported in either study. Cytopenias and cytokine release syndrome were the most common treatment-emergent AEs. Combining pembrolizumab with lete-cel did not appear to increase toxicity over lete-cel alone. Limited anti-tumor activity was observed; one of 18 patients had a durable response persisting for 18 months. Pharmacokinetic data showed similar T-cell expansion in all patients.

Conclusions: Extensive HLA-A*02 and antigen expression testing was performed to identify potential participants. Lete-cel was generally well tolerated and had no unexpected AEs. Anti-tumor activity was observed in a limited number of patients.