Combined inhibition of CXCL12 and PD-1 in MSS colorectal and pancreatic cancer: modulation of the microenvironment and clinical effects.

BACKGROUND: Immunotherapy in microsatellite stable colorectal or pancreatic cancer has not shown promising results. It has been hypothesized that targeting immunosuppressive molecules like SDF1-alpha/CXCL12 could contribute to immunotherapy and animal models showed promising results on T cell activation and migration in combination with immune checkpoint inhibition. METHODS: Here, we describe the successful application of anti-CXCL12 (NOX-A12) in patients with advanced stage pretreated metastatic colorectal and pancreatic cancer (OPERA trial). The treatment consisted of 2 weeks of anti-CXCL12 monotherapy with NOX-A12 followed by combination therapy with pembrolizumab (n=20 patients) until progression or intolerable toxicity had occurred. RESULTS: The treatment was safe and well tolerated with 83.8% grade I/II, 15.5% grade III and 0.7% grade V adverse events. Of note, for a majority of patients, time on trial treatment was prolonged compared with their last standard treatment preceding trial participation. Systematic serial biopsies revealed distinct patterns of modulation. Tissue and clinical responses were associated with Th1-like tissue reactivity upon CXCL12 inhibition. A downregulation of a cytokine cassette of interleukin (IL)-2/IL-16/CXCL-10 was associated with tumor resistance and furthermore linked to a rare, CXCL12-associated CD14+CD15+promonocytic population. T cells showed aggregation and directed movement towards the tumor cells in responding tissues. Serum analyses detected homogeneous immunomodulatory patterns in all patients, regardless of tissue responses. CONCLUSIONS: We demonstrate that the combination of CXCL12 inhibition and checkpoint inhibition is safe and grants further exploration of synergistic combinatorial strategies.

Phase 2 Trial of Oncolytic H-1 Parvovirus Therapy Shows Safety and Signs of Immune System Activation in Patients With Metastatic Pancreatic Ductal Adenocarcinoma.

PURPOSE: To investigate the safety, clinical efficacy, virus pharmacokinetics, shedding, and immune response after administration of an oncolytic parvovirus (H-1PV, ParvOryx) to patients with metastatic pancreatic ductal adenocarcinoma (PDAC) refractory to first-line therapy. PATIENTS AND METHODS: This is a noncontrolled, single-arm, open-label, dose-escalating, single-center clinical trial. Seven patients with PDAC and at least one liver metastasis were included. ParvOryx was administered intravenously on 4 consecutive days and as an intralesional injection, 6 to 13 days thereafter. Altogether, three escalating dose levels were investigated. In addition, gemcitabine treatment was initiated on day 28. RESULTS: ParvOryx showed excellent tolerability with no dose-limiting toxicities. One patient had a confirmed partial response and one patient revealed an unconfirmed partial response according to RECIST criteria. Both patients showed remarkably long surivial of 326 and 555 days, respectively. Investigation of pharmacokinetics and virus shedding revealed dose dependency with no excretion of active virus particles in saliva or urine and very limited excretion in feces. H-1PV nucleic acids were detected in tumor samples of four patients. All patients showed T-cell responses to viral proteins. An interesting immunologic pattern developed in tumor tissues and in blood of both patients with partial response suggesting immune activation after administration of ParvOryx. CONCLUSIONS: The trial met all primary objectives, revealed no environmental risks, and indicated favorable immune modulation after administration of ParvOryx. It can be considered a good basis for further systematic clinical development alone or in combination with immunomodulatory compounds.