Purpose: Human Vα24 natural killer T (NKT) cells bearing an invariant Vα24JαQ antigen receptor, the counterpart of murine Vα14 NKT cells, are activated by a specific ligand, α-galactosylceramide (αGalCer, KRN7000), in a CD1d-dependent manner. I.v. administration of αGalCer-pulsed dendritic cells (DC) induces significant activation and expansion of Vα14 NKT cells in the lung and resulting potent antitumor activities in mouse tumor metastatic models. We did a phase I dose escalation study with αGalCer-pulsed DCs in lung cancer patients.

Experimental Design: Patients with advanced non–small cell lung cancer or recurrent lung cancer received i.v. injections of αGalCer-pulsed DCs (level 1: 5 × 10⁷/m²; level 2: 2.5 × 10⁸/m²; and level 3: 1 × 10⁹/m²) to test the safety, feasibility, and clinical response. Immunomonitoring was also done in all completed cases.

Results: Eleven patients were enrolled in this study. No severe adverse events were observed during this study in any patient. After the first and second injection of αGalCer-pulsed DCs, dramatic increase in peripheral blood Vα24 NKT cells was observed in one case and significant responses were seen in two cases receiving the level 3 dose. No patient was found to meet the criteria for partial or complete responses, whereas two cases in the level 3 group remained unchanged for more than a year with good quality of life.

Conclusions: In this clinical trial, αGalCer-pulsed DC administration was well tolerated and could be safely done even in patients with advanced disease.