Pilot and feasibility trial evaluating immuno-gene therapy of malignant mesothelioma using intrapleural delivery of adenovirus-IFNa combined with chemotherapy

Purpose: "In situ vaccination" using immunogene therapy has the ability to induce polyclonal antitumor responses directed by the patient's immune system. Experimental Design: Patients with unresectable malignant pleural mesothelioma (MPM) received two intrapleural doses of a replication-defective adenoviral vector containing the human IFNα2b gene (Ad.IFN) concomitant with a 14-day course of celecoxib followed by chemotherapy. Primary outcomes were safety, toxicity, and objective response rate; secondary outcomes included progression-free and overall survival. Biocorrelates on blood and tumor were measured. Results: Forty subjects were treated: 18 received first-line pemetrexed-based chemotherapy, 22 received second-line chemotherapy with pemetrexed (n = 7) or gemcitabine (n = 15). Treatment was generally well tolerated. The overall response rate was 25%, and the disease control rate was 88%. Median overall survival (MOS) for all patients with epithelial histology was 21 months versus 7 months for patients with nonepithelial histology. MOS in the first-line cohort was 12.5 months, whereas MOS for the second-line cohort was 21.5 months, with 32% of patients alive at 2 years. No biologic parameters were found to correlate with response, including numbers of activated blood T cells or NK cells, regulatory T cells in blood, peak levels of IFNα in blood or pleural fluid, induction of antitumor antibodies, nor an immune-gene signature in pretreatment biopsies. Conclusions: The combination of intrapleural Ad.IFN, celecoxib, and chemotherapy proved safe in patients with MPM. OS rate was significantly higher than historical controls in the second-line group. Results of this study support proceeding with a multicenter randomized clinical trial of chemoimmunogene therapy versus standard chemotherapy alone.