Phase I Clinical Trial of Systemically Administered <em>TUSC2(FUS1)-</em>Nanoparticles Mediating Functional Gene Transfer in Humans

<div><h3>Background</h3><p>Tumor suppressor gene <em>TUSC2/FUS1 (TUSC2)</em> is frequently inactivated early in lung cancer development. <em>TUSC2</em> mediates apoptosis in cancer cells but not normal cells by upregulation of the intrinsic apoptotic pathway. No drug strategies currently exist targeting loss-of–function genetic abnormalities. We report the first in-human systemic gene therapy clinical trial of tumor suppressor gene <em>TUSC2</em>.</p> <h3>Methods</h3><p>Patients with recurrent and/or metastatic lung cancer previously treated with platinum-based chemotherapy were treated with escalating doses of intravenous <em>N</em>-[1-(2,3-dioleoyloxy)propyl]-<em>N</em>,<em>N</em>,<em>N</em>-trimethylammonium chloride (DOTAP):cholesterol nanoparticles encapsulating a <em>TUSC2</em> expression plasmid (DOTAP:chol-<em>TUSC2</em>) every 3 weeks.</p> <h3>Results</h3><p>Thirty-one patients were treated at 6 dose levels (range 0.01 to 0.09 milligrams per kilogram). The MTD was determined to be 0.06 mg/kg. Five patients achieved stable disease (2.6–10.8 months, including 2 minor responses). One patient had a metabolic response on positron emission tomography (PET) imaging. RT-PCR analysis detected <em>TUSC2</em> plasmid expression in 7 of 8 post-treatment tumor specimens but not in pretreatment specimens and peripheral blood lymphocyte controls. Proximity ligation assay, performed on paired biopsies from 3 patients, demonstrated low background TUSC2 protein staining in pretreatment tissues compared with intense (10–25 fold increase) TUSC2 protein staining in post-treatment tissues. RT-PCR gene expression profiling analysis of apoptotic pathway genes in two patients with high post-treatment levels of TUSC2 mRNA and protein showed significant post-treatment changes in the intrinsic apoptotic pathway. Twenty-nine genes of the 82 tested in the apoptosis array were identified by Igenuity Pathway Analysis to be significantly altered post-treatment in both patients (Pearson correlation coefficient 0.519; p<0.01).</p> <h3>Conclusions</h3><p>DOTAP:chol-<em>TUSC2</em> can be safely administered intravenously in lung cancer patients and results in uptake of the gene by human primary and metastatic tumors, transgene and gene product expression, specific alterations in <em>TUSC2</em>-regulated pathways, and anti-tumor effects (to our knowledge for the first time for systemic DOTAP:cholesterol nanoparticle gene therapy).</p> <h3>Trial Registration</h3><p>ClinicalTrials.gov <a href="http://www.clinicaltrials.gov/ct2/show/NCT00059605">NCT00059605</a></p>