Abstract CT117: Phase 1/2 study with CXCL12 inhibitor NOX-A12 and pembrolizumab in patients with microsatellite-stable, metastatic colorectal or pancreatic cancer

Abstract

Abstract Background: NOX-A12 is an inhibitor of the chemokine CXCL12 which prevents engagement with its receptors CXCR4 and CXCR7 and blocks the formation of chemotactic CXCL12 concentration gradients in tissue. The Opera study (NCT03168139) is a Phase 1/2 study to evaluate pharmacodynamic effects and safety of monotherapy with NOX-A12 as well as safety and efficacy of a combination with pembrolizumab in metastatic microsatellite-stable colorectal and pancreatic cancer where PD-1 inhibition alone has not shown clinical benefit. Methods: Patients received 300 mg NOX-A12 twice weekly during a 2-week monotherapy phase. Biopsies were taken from liver metastases before and after NOX-A12 monotherapy for analysis of immune cell infiltration and cytokine signature. In a combination phase, patients received repeated 21-day cycles of 300 mg NOX-A12 and 200 mg pembrolizumab until progression or intolerable toxicity. Results: 11 of the patients had CRC and 9 PaC. All patients were heavily pretreated with 5 (colorectal cancer) and 3 median lines (pancreatic cancer) of prior treatment. Best responses to last prior treatment was progressive disease for 95% of patients. The AE profile was comparable with the pembrolizumab profile or typical for the underlying diseases. Two weeks of NOX-A12 monotherapy induced Th1 cytokines (IFNγ, IL-2, IL-16) in approx. half of the patients. Comparison of tumor biopsies from before and after NOX-A12 monotherapy shows trends towards (i) agglomeration of T cells and (ii) migration of T cells towards cancer cells in the patient sub-group where NOX-A12 induced a Th1-type cytokine response. These trends are consistent with preclinical data (Feig 2013, PNAS 110:20212; Zboralski 2017, Cancer Immunol Res 5:950), suggesting that neutralization of CXCL12 signaling - either through one or both receptors - increased infiltration of effector immune cells into tumor tissue and resulted in a more effective immune response. Although there were no objective responses, 25% of patients achieved stable disease; 7 patients showed prolonged time on treatment vs. the prior line of therapy. Median progression-free survival was 1.87 months, overall survival was 42% at 6 months and 22% at 12 months. Conclusions: A trend towards agglomeration of T cells within tumors was observed in about half of the patients where NOX-A12 had induced a Th1-type cytokine response. This agglomeration was accompanied by reduced distances between T cells and cancer cells, suggesting increased infiltration of effector immune cells into tumor tissue. Treatment with NOX-A12 plus pembrolizumab in the combination therapy part of the study resulted in stable disease in 25% of patients, and prolonged time on treatment vs. prior therapy for 35% of patients. The safety profile of the combination therapy was consistent with that of pembrolizumab in advanced cancer patients. Citation Format: Niels Halama, Anja Williams, Ulrike Prüfer, Anna Frömming, Diana Beyer, Dirk Eulberg, Jarl Ulf Jungnelius, Aram Mangasarian. Phase 1/2 study with CXCL12 inhibitor NOX-A12 and pembrolizumab in patients with microsatellite-stable, metastatic colorectal or pancreatic cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT117.