Adoptive Transfer of Autologous Invariant Natural Killer T Cells as Immunotherapy for Advanced Hepatocellular Carcinoma: A Phase I Clinical Trial

Lessons learned Administration of autologous invariant natural killer T (iNKT) cells was safe and well-tolerated in patients with hepatocellular carcinoma (Barcelona Clinic Liver Cancer stage B/C). Expanded iNKT cells produced T-helper 1-like responses with possible antitumor activity. No severe adverse events were observed in any of the enrolled patients, including one patient who received 1010 in vitro-expanded autologous iNKT cells as a single infusion. Background Invariant natural killer T cells co-express T-cell antigen receptor and natural killer (NK) cell receptors. Invariant natural killer T (iNKT) cells exhibit antitumor activity, but their numbers and functions are impaired in patients with hepatocellular carcinoma (HCC). The adoptive transfer of iNKT cells might treat advanced HCC. Methods This phase I study (NCT03175679) enrolled 10 patients with HCC (Barcelona Clinic Liver Cancer [BCLC] stage B/C) at Beijing YouAn Hospital (April 2017 to May 2018). iNKT cells isolated from peripheral blood mononuclear cells (PBMCs) were expanded and alpha-galactosylceramide (α-GalCer)-pulsed. Dosage escalated from 3 × 107 to 6 × 107 to 9 × 107 cells/m2 (3+3 design). An exploratory dose trial (1 × 1010 cells/m2 ) was conducted in one patient. Results Expanded iNKT cells produced greater quantities of T-helper 1 (Th1) cytokines (e.g., interferon-gamma, perforin, and granzyme B) but less interleukin-4 than nonexpanded iNKT cells. Circulating numbers of iNKT cells and activated NK cells were increased after iNKT cell infusion. Most treatment-related adverse events were grade 1-2, and three grade 3 adverse events were reported; all resolved without treatment. Four patients were progression-free at 5.5, 6, 7, and 11 months after therapy, and one patient was alive and without tumor recurrence at the last follow-up. Five patients died at 1.5 to 11 months after treatment. Conclusion Autologous iNKT cell treatment is safe and well-tolerated. Expanded iNKT cells produce Th1-like responses with possible antitumor activity. The antitumor effects of iNKT cell infusion in patients with advanced HCC merit further investigation.