Preclinical activity and manufacturing feasibility of genetically modified PDCD-1 knockout (KO) tumor-infiltrating lymphocyte (TIL) cell therapy (AACR 2022)
Background: Adoptive cell therapy with autologous TIL has demonstrated an objective response rate (ORR) of 36% in the post-immune checkpoint inhibitor (ICI) setting in patients (pts) with advanced/unresectable melanoma (Sarnaik JCO 2021), while in ICI-naïve pts who received early-line combination of TIL and pembrolizumab, the ORR was 60%, with a 30% CR rate (O’Malley SITC 2021). Although effective, anti-PD-1 therapy is limited by poor penetration into the tumor, internalization, and endocytic clearance, in contrast with TIL, which overcome this inherent limitation... Anti-tumor activity of PD-1 KO TIL was superior to mock TIL suggesting that endogenous PD-1 inhibition may confer a functional advantage to the TIL over an antibody combination. PD-1 KO TIL clinical manufacturing was feasible and the TIL product quality attributes and phenotype were acceptable; importantly, lack of complete PD-1 KO may spare other PD-1-dependent in vivo cellular functions. Together, these data support clinical investigation of IOV-4001, an autologous PD-1 KO TIL cell therapy.