Phase I Trial of Induction Histone Deacetylase and Proteasome Inhibition Followed by Surgery in Non–Small-Cell Lung Cancer

Abstract

Despite complete surgical resection survival in early-stage non-small-cell lung cancer (NSCLC) remains poor. On the basis of prior preclinical evaluations, we hypothesized that combined induction proteasome and histone deacetylase inhibitor therapy, followed by tumor resection, is feasible. A phase I clinical trial using a two-staged multiple-agent design of bortezomib and vorinostat as induction therapy followed by consolidative surgery in patients with NSCLC was performed. Standard toxicity and maximum tolerated dose were examined. Pre- and post-treatment tumor gene-expression arrays were performed and analyzed. Pre- and post-treatment fluorodeoxyglucose-positron emission tomography imaging was used to assess tumor metabolism. Finally, serum 20S proteasome levels were analyzed with enzyme-linked immunosorbent assay, and selected intratumoral proteins were assessed by immunohistochemistry. Of the 34-four patients providing written consent to participate in the trial, 21 were enrolled. One patient withdrew early because of disease progression. The maximum tolerated dose was bortezomib 1.3 mg/m and vorinostat 300 mg twice daily. There were grade III dose-limiting toxicities of fatigue and hypophosphatemia, which were self-limited. There was no mortality. Thirty percent of patients (6 of 20) had more than 60% histologic necrosis of their tumor after treatment, with two having 90% or more tumor necrosis. Tumor metabolism, 20S proteasome activity, and specific protein expression did not demonstrate consistent results. Gene-expression arrays comparing pre- and post-therapy NSCLC specimens revealed robust intratumoral changes in specific genes. Induction bortezomib and vorinostat therapy followed by surgery in patients with operable NSCLC is feasible. Correlative gene-expression studies suggest new targets and cell-signaling pathways that may be important in modulating this combined therapy.