We report a phase I/II clinical trial in prostate cancer (PCa) using direct intraprostatic injection of a replication defective adenovirus vector (CTL102) encoding bacterial nitroreductase (NTR) in conjunction with systemic prodrug CB1954. One group of patients with localized PCa scheduled for radical prostatectomy received virus alone, prior to surgery, in a dose escalation to establish safety, tolerability, and NTR expression. A second group with local failure following primary treatment received virus plus prodrug to establish safety and tolerability. Based on acceptable safety data and indications of prostate-specific antigen (PSA) responses, an extended cohort received virus at a single dose level plus prodrug. The vector was well tolerated with minimal side effects, had a short half-life in the circulation, and stimulated a robust antibody response. Immunohistochemistry of resected prostate demonstrated NTR staining in tumor and glandular epithelium at all dose levels [5 x 10(10)-1 x 10(12) virus particles (vp)]. A total of 19 patients received virus plus prodrug and 14 of these had a repeat treatment; minimal toxicity was observed and there was preliminary evidence of change in PSA kinetics, with an increase in the time to 10% PSA progression in 6 out of 18 patients at 6 months.

There is a growing recognition that current preclinical models do not reflect the tumor microenvironment in cellular, biological, and biophysical content and this may have a profound effect on drug efficacy testing, especially in the era of molecular-targeted agents. Here, we describe a method to directly embed low-passage patient tumor-derived tissue into basement membrane extract, ensuring a low proportion of cell death to anoikis and growth complementation by coculture with patient-derived cancer-associated fibroblasts (CAF). A range of solid tumors proved amenable to growth and pharmacologic testing in this 3D assay. A study of 30 early-stage non-small cell lung cancer (NSCLC) specimens revealed high levels of de novo resistance to a large range of standard-of-care agents, while histone deacetylase (HDAC) inhibitors and their combination with antineoplastic drugs displayed high levels of efficacy. Increased resistance was seen in the presence of patient-derived CAFs for many agents, highlighting the utility of the assay for tumor microenvironment-educated drug testing. Standard-of-care agents showed similar responses in the 3D ex vivo and patient-matched in vivo models validating the 3D-Tumor Growth Assay (3D-TGA) as a high-throughput screen for close-to-patient tumors using significantly reduced animal numbers. Mol Cancer Ther; 15(4); 753-63. Ó2016 AACR.

The complex interplay of the tumour microenvironment (TME) and its role in disease progression and response to therapy is poorly understood. The majority of studies to date focus on individual components or molecules within the TME and so lack the power correlative analysis. Here we have performed a multi-parameter analysis of the TME in 62 resectable non-small cell lung cancer (NSCLC) specimens detailing number and location of immune infiltrate, assessing markers of cancer-associated fibroblasts, caveolin-1 and tenascin-C, and correlating with clinicopathological details, as well as markers of disease progression such as epithelial-to-mesenchymal transition (EMT). The influence of individual parameters on overall survival was determined in univariate and multivariate analysis and the combination of risk factors and interplay between components analysed. Low numbers of CD8 T cells, low stromal levels of caveolin-1 or high levels of tenascin-C were significant prognostic markers of decreased overall survival in both univariate and multivariate analysis. Patients with two or more risk factors had dramatically reduced overall survival and those with all three a median survival of just 7.5 months. In addition, low levels of tumour E-cadherin correlated with reduced immune infiltrate into the tumour nests, possibly linking EMT to the avoidance of CD8 T cell control. The multicomponent approach has allowed identification of the dominant influences on overall survival, and exploration of the interplay between different components of the TME in NSCLC.

We have completed a phase I/II suicide gene therapy clinical trial in patients with prostate cancer, using an E1/E3-deleted replication-deficient adenovirus (CTL102) encoding the bacterial nitroreductase enzyme in combination with prodrug CB1954. This study has provided an opportunity to monitor and characterize vector- and tumor-specific adaptive immunity before and after single or repeat injections of adenovirus. Here we report robust vector-specific humoral and cellular immune responses in all patients monitored. However, we found no correlation between preexisting immunity or the magnitude of the immune response to vector and the clinical outcome as measured by changes in serum prostate-specific antigen (PSA) level. Increased frequency of T cells recognizing prostate-specific antigens PSA or prostate-specific membrane antigen (PSMA) was detected in 3 of 11 patients after therapy, suggesting that this direct cytotoxic strategy can also stimulate tumor-specific immunity.