Phase I trial of ADP-A2AFP TCR T-cell therapy in patients with advanced hepatocellular or gastric hepatoid carcinoma.

[BACKGROUND & AIMS] Patients with advanced hepatocellular carcinoma (HCC) generally experience poor outcomes despite current therapies, necessitating the development of alternative treatments. ADP-A2AFP is an investigational autologous T-cell therapy with an affinity-enhanced T-cell receptor (TCR) targeting alpha-fetoprotein (AFP).

[METHODS] We describe a phase I, open-label, first-in-human clinical trial of ADP-A2AFP (NCT03132792) in human leukocyte antigen-eligible participants with AFP-expressing HCC (or other tumor) not amenable to transplant/resection who progressed on, were intolerant to, or refused prior systemic therapy. Participants received lymphodepletion chemotherapy (cyclophosphamide 500 mg/m/day for 3 days and fludarabine 20 mg/m/day for 3 days, or cyclophosphamide 600 mg/m/day for 3 days and fludarabine 30 mg/m/day for 4 days) followed by ADP-A2AFP intravenous infusion. Safety evaluation was the primary objective; response per RECIST v1.1 was the key secondary endpoint.

[RESULTS] Twenty-one participants, 20 with advanced HCC and one with gastric hepatoid carcinoma received ≥1 ADP-A2AFP infusion. All participants experienced ≥1 grade 3 or higher adverse event; 52.4% experienced ≥1 grade 3 or higher event considered related to ADP-A2AFP treatment. Six participants experienced cytokine release syndrome (grade 1-2: n = 5; grade 4: n = 1). Best overall responses were complete response (n = 1), partial response (n = 1), and stable disease (n = 12); overall response rate was 9.5%. Eight patients had a stable disease duration of ≥16 weeks. Infiltration of ADP-A2AFP TCR and CD8+ T cells was seen in AFP-positive areas of post-treatment tumor samples. A relationship was demonstrated between increased ADP-A2AFP dose and serum AFP reduction in responders.

[CONCLUSIONS] Lymphodepletion chemotherapy followed by ADP-A2AFP TCR T-cell therapy showed a manageable safety profile and preliminary indications of antitumor activity in these previously treated patients.

[IMPACT AND IMPLICATIONS] Adoptive T-cell therapy could be a much-needed additional treatment strategy for advanced hepatocellular carcinoma. Clinicians and researchers interested in the development of adoptive T-cell therapies for advanced solid tumors will be interested to learn that in this phase I trial, ADP-A2AFP T-cell receptor T-cell therapy was associated with an acceptable benefit-to-risk profile and encouraging antitumor activity, illustrating the treatment potential of adoptive T-cell therapy for advanced hepatocellular carcinoma.

[GOV NUMBER] NCT03132792; first posted 2017-04-08.