Adaptimmune Therapeutics plc announced updated data from its Phase 1 ADP-A2AFP trial for patients with liver cancer at ILCA. Topline results from the ADP-A2AFP Phase 1 trial as of the April 5, 2021 data cutoff; Efficacy; Thirteen patients with advanced hepatocellular carcinoma (HCC) received ADP-A2AFP in Cohort 3 and expansion. The best overall responses in Cohort 3 and expansion (per RECIST v1.1) included 1 complete response (reported in 2020), 6 stable disease and 4 progressive disease. 2 patients did not have scan results at the time of data cut-off. The disease control rate for patients with at least one scan was 7/11 (64%) and 2 patients had stable disease lasting beyond 16 weeks. Safety; ADP-A2AFP has an acceptable safety profile with no reports of significant T-cell related hepatotoxicity and no protocol-defined dose limiting toxicities. Adverse events (AEs) reported in 2 or more patients and considered related to T-cell infusion included neutropenia, leukopenia, lymphopenia, pyrexia, anemia, cytokine release syndrome, febrile neutropenia, thrombocytopenia, aspartate aminotransferase increased, and alanine aminotransferase increased. Two patients reported a total of 3 treatment-related serious AEs including cytokine release syndrome (Grade 1), infusion-related reaction (Grade 2), and febrile neutropenia (Grade 3). Conclusions; Antitumor activity, with one complete response, sustained decreases in serum AFP, and best overall response of stable disease observed in 6 patients, indicate that ADP-A2AFP is an active product in HCC. ADP-A2AFP up to doses of 10 billion transduced cells has been associated with an acceptable safety profile. Overview of Trial Design; This is a Phase 1, open-label, dose escalation clinical trial designed to evaluate the safety and anti-tumor activity of ADP-A2AFP in patients with liver cancer (hepatocellular carcinoma) or other AFP-expressing tumors, who are not amenable to transplant, resection, or loco-regional therapy, and who failed or were intolerant to or refused standard-of-care treatment. Dose escalation is complete, and this trial is intended to treat up to 25 patients with doses up to 10 billion transduced cells in the expansion phase.