Phase II trial of a GM-CSF-producing and CD40L-expressing cell line combined with allogeneic tumor antigen as a novel vaccine for metastatic lung adenocarcinoma.

Abstract

2559 Background: We created a vaccine in which irradiated allogeneic lung adenocarcinoma cells are combined with a bystander K562 cell line transfected with hCD40L and hGM-CSF. By recruiting and activating dendritic cells, we hypothesized the vaccine would induce tumor regression in metastatic lung adenocarcinoma. Methods: Intradermal vaccine was given every 14 days x3, followed by monthly x3. Cyclophosphamide (300 mg/m2 IV) was administered before 1st and 4th vaccines to deplete regulatory T-cells. All-trans retinoic acid was given (150/mg/m2/day) after 1st and 4th vaccines to enhance dendritic differentiation. Peripheral blood mononuclear cells (PBMCs) were collected at baseline and after each vaccination. T-cell activation profiles were analyzed by ELISpot assay and tested by generalized Wilcoxon for correlation to survival. Results: 24 participants were accrued at a single center from 10/2006 to 6/2008, with median age 64 and median of 3 previous lines of chemotherapy prior to entry. 20 were former smokers and 4 had brain metastases. A total of 101 vaccines were administered. Common toxicities of any grade were joint pain (79%) and fatigue (75%). Significant adverse events included a grade 3 hypotension and a grade 3 acute respiratory distress. No confirmed complete or partial radiologic responses were observed. Median overall survival (OS) was 8.0 mo (95% CI 3.5 – 12.5) and median time-to-progression was 2.4 mo (95% CI 0.3 – 4.6). Presence of HLA-A2 conferred reduced risk of progression (HR 0.37, 95% CI 0.14 -0.89, p=0.02) and trend to improved OS (HR 0.59, p = 0.06). Of 14 participants with evaluable PBMCs, 5 demonstrated sustained tumor peptide-specific T-cell activation after vaccination. Ex vivo peptide immune response correlated with improved OS compared to non-responders (23 vs. 7 mo, HR 0.48, p = 0.04). Conclusions: Vaccine administration was feasible and tolerable in a heavily pretreated population of metastatic lung cancer. These data suggest the vaccine has clinical activity in the subset with peptide-induced T-cell immune responses and warrants further investigation. A randomized trial of the vaccine is currently in development.