Biomarkers of immune switch induced by a novel anti-macrophage antibody (anti-Clever-1 mAb; FP-1305) in MATINS trial patients with advanced solid tumours

Abstract

Abstract Background A scavenger receptor CLEVER-1 is highly expressed on tumor associated macrophages (TAMs) and mediates the clearance of “unwanted” self-components. Pre-clinical studies demonstrate that CLEVER-1 inhibition increases TAM pro-inflammatory cytokine secretion and antigen presentation reactivating CD8+ T cell responses with robust anti-tumor activity (Viitala et al., 2019). Targeting CLEVER-1 could overcome the immunosuppressive tumor microenvironment and has led to the development of FP-1305, a humanized anti-CLEVER-1 IgG4-antibody. Methods MATINS (Macrophage Antibody To INhibit immune Suppression) trial is a multicenter first-in-human phase I/II study (NCT03733990) to assess the tolerability, safety and preliminary efficacy of FP-1305 in patients with advanced, IO-refractory melanoma, cholangiocarcinoma, hepatocellular, colorectal, and pancreatic ductal adenocarcinoma. Biomarker analysis included CLEVER-1 determination, immune cell profiling by mass cytometry and analysis of cytokine production. Results 11 patients (median age 57) were enrolled in four cohorts (0.3, 1.0, 3.0 or 10\u2009mg/kg) and received 1-8 cycles (median 3) of FP-1305 every three weeks. FP-1305 has been well tolerated without dose-limiting toxicities and maximum tolerated dose (MTD) has not been reached. Promising early efficacy results have recently been reported (ESMO 2019, LBA19). FP-1305 dosing led to increased Th1 skewing (CXCR3+CCR6-) of CD4 and CD8 T cell populations with downregulation of several inhibitory immune checkpoint molecules. Increase in circulating IFN gamma was detected but it was most prominent in the patient showing durable partial response. Conclusion FP-1305 is the first macrophage checkpoint inhibitor candidate promoting immune switch with promising tolerability and clinical anti-tumor activity. FP-1305 represents a novel treatment option to provoke immune response against cold tumors. Clinical trial identification NCT03733990. Legal entity responsible for the study Faron Pharmaceuticals. Funding Finnish Academy, Finnish Cancer Foundations, Sigrid Juselius Foundation, Faron Pharmaceuticals. Disclosure M. Hollmen: Research grant / Funding (institution), Travel / Accommodation / Expenses, Shareholder / Stockholder / Stock options: Faron Pharmaceuticals. P. Jaakkola: Advisory / Consultancy: Faron Pharmaceuticals. A. Minchom: Advisory / Consultancy: Faron Pharmaceuticals. S. Jalkanen: Shareholder / Stockholder / Stock options: Faron Pharmaceuticals. M. Karvonen: Shareholder / Stockholder / Stock options, Full / Part-time employment: Faron Pharmaceuticals. J. Mandelin: Shareholder / Stockholder / Stock options, Full / Part-time employment: Faron Pharmaceuticals. J. Koivunen: Advisory / Consultancy: Faron Pharmaceuticals; Advisory / Consultancy: Novartis; Advisory / Consultancy: Pfizer; Advisory / Consultancy: Boehringer-Ingelheim; Advisory / Consultancy: KaikuHealth. P. Bono: Advisory / Consultancy, Travel / Accommodation / Expenses, Spouse / Financial dependant: Faron Pharmaceuticals; Advisory / Consultancy, Travel / Accommodation / Expenses: MSD; Advisory / Consultancy: Pfizer; Advisory / Consultancy: Novartis; Advisory / Consultancy: Bristol-Myers Squibb; Advisory / Consultancy: OrionPharma. All other authors have declared no conflicts of interest.