Immunization of NSCLC patients with antigen-pulsed immature autologous dendritic cells

Only a handful of NSCLC patients have been included in dendritic cell (DC) vaccine clinical trials. We had previously reported a series of 16 individuals with stages IA-IIIB NSCLC who received autologous DC vaccines matured with dendritic cell/T cell-derived maturation factor (DCTCMF). Here we report the results of a continuation study with similar inclusion criteria, immunization protocol, and analysis, using an immature DC vaccine. Of the 14 participants, 7 had undergone surgical resection (stage I/II), with or without adjuvant therapy, and 7 with unresectable stage III had been treated with chemo-radiation alone. Autologous DCs were pulsed with apoptotic bodies derived from an allogeneic NSCLC cell line that over-expresses Her2/neu, CEA, WT1, Mage2, and survivin. DCs were not exposed to any maturation stimulus. Individuals received two intradermal vaccines (average 8.1 × 10⁷ DC per immunization) 1 month apart. Immune responses were measured by IFN-γ ELISPOT, comparing relative number of antigen-reactive T-cells from pre-vaccine to timepoints post-immunization. Immunologic responses were seen in 4/7 stage III unresectable, and 6/7 stage I/II surgically resected patients, including 3/3 resected patients who had also received adjuvant chemo-radiation. There were no related adverse events. One of seven surgically resected patients recurred and 4/7 stage III patients progressed. Three of five patients with progressive disease showed no immunologic response. Data indicate that immature DC pulsed with apoptotic tumour cells have similar biologic activity to a DCTCMF-matured DC preparation delivered in a similar clinical protocol. Therapeutic efficacy is unknown and clinical outcomes are anecdotal.