Oncolytic virus driven T-cell-based combination immunotherapy platform for colorectal cancer.

Colorectal cancer is the third most diagnosed cancer and the second leading cause of cancer mortality worldwide, highlighting an urgent need for new therapeutic options and combination strategies for patients. The orchestration of potent T cell responses against human cancers is necessary for effective antitumour immunity. However, regression of a limited number of cancers has been induced by immune checkpoint inhibitors, T cell engagers (TCEs) and/or oncolytic viruses. Although one TCE has been FDA-approved for the treatment of hematological malignancies, many challenges exist for the treatment of solid cancers. Here, we show that TCEs targeting CEACAM5 and CD3 stimulate robust activation of CD4 and CD8-positive T cells in in vitro co-culture models with colorectal cancer cells, but in vivo efficacy is hindered by a lack of TCE retention in the tumour microenvironment and short TCE half-life, as demonstrated by HiBiT bioluminescent TCE-tagging technology. To overcome these limitations, we engineered Bispecific Engager Viruses, or BEVirs, a novel tumour-targeted vaccinia virus platform for intra-tumour delivery of these immunomodulatory molecules. We characterized virus-mediated TCE-secretion, TCE specificity and functionality from infected colorectal cancer cells and patient tumour samples, as well as TCE cytotoxicity in spheroid models, in the presence and absence of T cells. Importantly, we show regression of colorectal tumours in both syngeneic and xenograft mouse models. Our data suggest that a different profile of cytokines may contribute to the pro-inflammatory and immune effects driven by T cells in the tumour microenvironment to provide long-lasting immunity and abscopal effects. We establish combination regimens with immune checkpoint inhibitors for aggressive colorectal peritoneal metastases. We also observe a significant reduction in lung metastases of colorectal tumours through intravenous delivery of our oncolytic virus driven T-cell based combination immunotherapy to target colorectal tumours and FAP-positive stromal cells or CTLA4-positive Treg cells in the tumour microenvironment. In summary, we devised a novel combination strategy for the treatment of colorectal cancers using oncolytic vaccinia virus to enhance immune-payload delivery and boost T cell responses within tumours.

Phase I study of docetaxel in combination with the P-glycoprotein inhibitor, zosuquidar, in resistant malignancies.

PURPOSE: To determine the maximum tolerated dose, dose-limiting toxicity, and pharmacokinetics of docetaxel infused over 1 hour when given in combination with oral zosuquidar to patients with resistant solid tumors. EXPERIMENTAL DESIGN: In cycle 1, patients received docetaxel alone. In subsequent cycles, zosuquidar was administered with docetaxel, which was escalated from 75 to 100 mg/m2. Zosuquidar was escalated from 100 to 300 mg/m2 every 8 hours on days 1 to 3 for a total of 7 doses, or from 400 to 500 mg every 12 hours for 2 doses administered 2 hours before docetaxel. The pharmacokinetics of docetaxel with and without zosuquidar administration were obtained. RESULTS: Thirty-six of 41 patients completed at least one cycle of docetaxel and zosuquidar. The maximum tolerated dose was docetaxel 100 mg/m2 and zosuquidar 500 mg every 12 hours for 2 doses. The most common toxicity was neutropenia. In 35 patients, zosuquidar produced minimal increases in the docetaxel peak plasma concentrations and area under the curve. Dosing over 3 days with zosuquidar (7 doses) did not show benefit over the 1-day dosing. Of the 36 patients, one patient had a partial response, and 14 patients had disease stabilization. CONCLUSIONS: Docetaxel at 75 or 100 mg/m2 and zosuquidar 500 mg 2 hours before docetaxel and 12 hours later is well tolerated. Zosuquidar minimally alters the pharmacokinetics of docetaxel, allowing full dose docetaxel to be given with this P-glycoprotein modulator. A Phase II study with this combination in advanced breast carcinoma is underway.