Abstract
PURPOSE: Growth and differentiation factor 15 (GDF15) is overexpressed in multiple solid tumors and is thought to exert immunosuppressive effects in the tumor microenvironment. AZD8853 is an anti-GDF15 mAb. PATIENTS AND METHODS: This first-in-human, phase I/IIa, open-label study (NCT05397171) assessed AZD8853 monotherapy in previously treated patients with advanced/metastatic microsatellite-stable colorectal cancer and urothelial carcinoma. The primary objective was safety including dose-limiting toxicities. Secondary objectives included efficacy, pharmacokinetics, and pharmacodynamics (PD), including free serum GDF15. Exploratory objectives included biomarkers of clinical activity and effects on cancer cachexia. RESULTS: During dose escalation, 16 patients received AZD8853 300 mg (n = 3), 1,000 mg (n = 6), or 3,000 mg (n = 7) intravenously every 3 weeks; 15 patients had microsatellite-stable colorectal cancer; and one patient had urothelial carcinoma. By June 6, 2023, all patients had discontinued treatment. Thirteen (81.3%) patients had treatment-emergent adverse events (TEAE); most commonly diarrhea (31.3%), abdominal pain (31.3%), and decreased appetite (25%). Eight (50.0%) patients had grade ≥3 TEAEs, and six (37.5%) had serious TEAEs, none treatment related. There were no dose-limiting toxicities. The best response per RECIST v1.1 was stable disease in five (31.3%) patients and disease progression in 11 (68.8%) patients. AZD8853 showed linear pharmacokinetics with a half-life of 5 to 10 days, supporting every 3 weeks dosing. AZD8853 suppression of GDF15 was transient. There was no evidence of ctDNA clearance or dose-dependent changes in peripheral T cells. Changes in body weight showed no apparent trends. CONCLUSIONS: AZD8853 was well tolerated; however, no objective responses or PD effects were seen, and GDF15 suppression was not sustained. The study was terminated after dose escalation. SIGNIFICANCE: GDF15 is upregulated in the tumor microenvironment and suppresses antitumor immune responses. In this first-in-human trial, the anti-GDF15 antibody AZD8853 was well tolerated in previously treated patients with advanced/metastatic solid tumors, but no objective responses or PD effects were seen and GDF15 suppression was not sustained.