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Purpose: The initial goal of this study was to test the immunologic and clinical effects of a new cancer vaccine consisting of dendritic cells (DC) transduced with the full-length wild-type p53 gene delivered via an adenoviral vector in patients with extensive stage small cell lung cancer. Experimental Design: Twenty-nine patients with extensive stage small cell lung cancer were vaccinated repeatedly at 2-week intervals. Most of the patients received three immunizations. p53-specific responses were evaluated, and phenotype and function of Tcells, DCs, and immature myeloid cells were analyzed and correlated with antigen-specific immune responses. Objective clinical response to vaccination as well as subsequent chemotherapy was evaluated.Results: p53-specificTcell responses to vaccination were observed in 57.1% of patients. Immunologic responses to vaccination were positively associated with a moderate increase in the titer of antiadenovirus antibodies, and negatively with an accumulation of immature myeloid cells. One patient showed a clinical response to vaccination whereas most of the patients had disease progression. However, we observed a high rate of objective clinical responses to chemotherapy (61.9%) that immediately followed vaccination. Clinical response to subsequent chemotherapy was closely associated with induction of immunologic response to vaccination. Conclusions: This study provides clinical support for an emerging paradigm in cancer immunotherapy, wherein optimal use of vaccination might be more effective, not as a separate modality, but in direct combination with chemotherapy.

BACKGROUND Allogeneic hematopoietic stem-cell transplantation for X-linked severe combined immunodeficiency (SCID-X1) often fails to reconstitute immunity associated with T cells, B cells, and natural killer (NK) cells when matched sibling donors are unavailable unless high-dose chemotherapy is given. In previous studies, autologous gene therapy with γ-retroviral vectors failed to reconstitute B-cell and NK-cell immunity and was complicated by vector-related leukemia. METHODS We performed a dual-center, phase 1–2 safety and efficacy study of a lentiviral vector to transfer IL2RG complementary DNA to bone marrow stem cells after low-exposure, targeted busulfan conditioning in eight infants with newly diagnosed SCID-X1. RESULTS Eight infants with SCID-X1 were followed for a median of 16.4 months. Bone marrow harvest, busulfan conditioning, and cell infusion had no unexpected side effects. In seven infants, the numbers of CD3+, CD4+, and naive CD4+ T cells and NK cells normalized by 3 to 4 months after infusion and were accompanied by vector marking in T cells, B cells, NK cells, myeloid cells, and bone marrow progenitors. The eighth infant had an insufficient T-cell count initially, but T cells developed in this infant after a boost of gene-corrected cells without busulfan conditioning. Previous infections cleared in all infants, and all continued to grow normally. IgM levels normalized in seven of the eight infants, of whom four discontinued intravenous immune globulin supplementation; three of these four in-fants had a response to vaccines. Vector insertion-site analysis was performed in seven infants and showed polyclonal patterns without clonal dominance in all seven. CONCLUSIONS Lentiviral vector gene therapy combined with low-exposure, targeted busulfan conditioning in infants with newly diagnosed SCID-X1 had low-grade acute toxic effects and resulted in multilineage engraftment of transduced cells, reconstitution of functional T cells and B cells, and normalization of NK-cell counts during a median follow-up of 16 months. (Funded by the American Lebanese Syrian Associated Charities and others; LVXSCID-ND ClinicalTrials.gov number, .)