Claudin18.2-targeted chimeric antigen receptor T cell-therapy for patients with gastrointestinal cancers: Final results of CT041-CG4006 phase 1 trial.

2501 Background: Autologous anti-claudin18.2 (CLDN18.2) CAR T cell, satricabtagene autoleucel (satri-cel)/CT041, was investigated in gastrointestinal cancers in clinical trials. The interim results of CT041-CG4006 trial (NCT03874897) were published in June 2022 [1]. Herein, we present the final results of this trial. Methods: This single-arm, open-label, phase 1 trial evaluated the safety and efficacy of CT041 in patients (pts) with CLDN18.2-positive advanced gastrointestinal (GI) cancers. The trial consisted of a dose-escalation (250×106, 375×106, 500×106 or 1000×106cells) using modified ‘3+3’ design and dose expansion of CT041 in 4 cohorts (Cohort 1: CT041 in pretreated pts with advanced GI cancers, Cohort 2: CT041 plus anti-PD-1 therapy in pretreated pts with advanced GI cancers, Cohort 3: CT041 sequential treatment following first-line therapy in gastric cancer (GC) and Cohort 4: CT041 in pts with prior failure to anti-CLDN18.2 antibody). The primary endpoint was safety; secondary endpoints were efficacy using RECIST v1.1, pharmacokinetics, and immunogenicity. Results: From 26 March 2019 to 26 January 2024, a total of 98 pts received CT041 infusion, including GC (n=73), pancreatic cancer (n=10), biliary tract cancer (n=4), intestinal cancer (n=8) and other tumors (n=3). A total of 89 pts were dosed with 250×106, 6 pts with 375×106, and 3 pts with 500×106 cells, with a median follow-up of 29.7 (range: 1.2, 35.5) months. 250×106 was selected for the dose-expansion stage based on the dose-escalation results. The most commonly reported treatment-emergent adverse events of grade 3 or higher were hematologic toxicity related to lymphodepletion. No dose-limiting toxicities, treatment-related deaths, or immune effector cell-associated neurotoxicity syndrome were reported. Cytokine release syndrome occurred in 96.9% of pts, all classified as grade 1-2. Gastric mucosal injuries were identified in 8 (8.2%) pts, including 7 cases of grade 1-2 and 1 case of grade 3 gastritis erosive which recovered. For all pts (N=98), the ORR and DCR reached 37.8% and 75.5%, respectively. The median PFS and median OS were 4.4 (95% CI: 4.0, 6.0) months and 8.4 (95% CI: 7.0, 10.0) months for all pts. Among efficacy evaluable GC pts who received CT041 monotherapy, the ORR and DCR in those with measurable disease (n=47) reached 57.4% and 83.0%, respectively, and the median PFS and median OS in all efficacy evaluable GC pts (n=55) were 5.8 (95% CI: 4.2, 8.4) months and 9.7 (95% CI: 7.1, 14.4) months, respectively. Conclusions: Satri-cel/CT041 demonstrated a promising safety profile and highly encouraging efficacy in heavily pretreated patients with CLDN18.2-positive advanced GI cancers. Clinical trial information: NCT03874897 .