A multi-modular phase I/II study of UCB6114, a first-in-class, fully human IgG4P anti-Gremlin-1 monoclonal antibody, as monotherapy and in combination with mFOLFOX6 or trifluridine/tipiracil, for patients with advanced gastrointestinal (GI) tumors

Abstract

Background: Despite recent advances, effective treatment for GI cancers remains a significant unmet medical need. Gremlin-1 is secreted by the peri-tumoral stroma and down-regulates bone morphogenetic proteins (BMP) -2, -4, and -7 (members of the transforming growth factor-β superfamily), thereby allowing malignant cell expansion, renewal, and a more treatment-resistant mesenchymal phenotype. Gremlin-1 mRNA is highly expressed in multiple solid tumors including >60% of colorectal, pancreatic and esophageal cancers. UCB6114 is a first-in-class, fully human IgG4P monoclonal antibody optimized for neutralizing the activity of human Gremlin-1 thereby restoring BMP signaling. Preclinical studies have demonstrated that UCB6114 binds to Gremlin-1, inhibits its pharmacological activity, and has antitumor activity in several in vivo mouse models (including several GI cancers). Methods: ONC001 (clinicaltrials.gov: NCT04393298) is an ongoing multi-part, multicenter, nonrandomized, open-label, Phase I/II study evaluating the safety, pharmacokinetics (PK) and antitumor activity of UCB6114 administered intravenously as monotherapy or in combination with selected standard of care (SOC) regimens. Eligible patients (pts) are: aged ≥18 years; resistant or refractory to standard therapy; ECOG performance status 0/1; and have adequate renal, hepatic and bone marrow function. In the Phase I monotherapy dose escalation and adaption part (part A and A1; modified rolling 6 design), up to 66 pts with advanced solid tumors associated with high levels of Gremlin-1 mRNA expression will be recruited. In parts B and C (modified toxicity probability interval design), up to 54 pts with locally advanced or metastatic colorectal, gastric or gastroesophageal junction adenocarcinomas will receive UCB6114 in escalating doses in combination with either mFOLFOX6 (5-fluorouracil, leucovorin and oxaliplatin) or trifluridine/tipiracil, given at SOC dosing and schedules. The overarching objective of the phase I parts of the study (Parts A‒C) is to identify the recommended phase II dose of UCB6114 either as monotherapy or in combination. The primary objective is to characterize the safety profile of UCB6114; secondary and exploratory objectives include PK, antitumor activity (RECIST v1.1), and pharmacodynamics (including circulating Gremlin-1). Enrollment in ONC001 began in July 2020; as of Sept 2021, four dose escalation levels in the monotherapy dose-escalation module (Part A) have been completed without DLT. Recruitment to parts B and C is due to commence in Q4 2021.