Abstract CT088: EVT801, a novel selective VEGFR-3 inhibitor targeting tumor angiogenesis, is pursuing dose escalation stage of phase I first-in-human study

Abstract Background: EVT801 is a highly selective, orally available VEGFR3 inhibitor that modulates tumor angiogenesis without inducing hypoxia, one of the main causes of cancer-associated immunosuppression. EVT801 has shown compelling efficacy as single agent in multiple in vivo models. In addition, combination of EVT801 and Immune Checkpoint Therapy (ICT) agents shows additive effects and thus holds promises for combination treatment without induction of hypoxia-induced immunosuppression. Clinical trial design: A phase I clinical study (NCT05114668) is underway to evaluate safety, tolerability, pharmacokinetics of EVT801 and explore patient characterization which is key for further development. The phase I trial consists in two sequential stages. During the first stage, currently ongoing, EVT801 is orally administered to patients with advanced solid tumors in a multiple ascending dose study using an accelerated 3+3 design (1 patient per dose until grade 2 toxicities are observed) in up to 48 patients in 8 dose levels. The primary objective is to determine the maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D). Stage 2 will focus on validation of this RP2D in two 6-patient cohorts diagnosed with 2 indications. In addition to conventional measures of safety, tolerability, efficacy, and pharmacokinetics, the phase I study employs a rich suite of biomarkers analysis using histology, transcriptomics and immunomonitoring to provide early insights into the pharmacological activity of EVT801. At end of September 2023, 20 patients have been treated in five different cohorts for EVT801 doses ranging from 50mg QD to 400mg BID. At this date, only 1 dose limiting toxicity was declared at the higher dose. Conclusion: Collection of safety data on these first enrolled patients showed no safety alert which allows further dose escalation and reinforces the good safety profile of EVT801 observed during the preclinical toxicology studies. Citation Format: Carlos Gomez-Roca, Philippe Cassier, Michael Fitzgerald, Lise Davenne, Cristina Costantin, Philippe Rochaix, Jean-Pierre Delord, John Friend, Andrea Nizzardo, Alessia Tagliavini, Marco Pergher, Pierre Fons, Marie Mandron. EVT801, a novel selective VEGFR-3 inhibitor targeting tumor angiogenesis, is pursuing dose escalation stage of phase I first-in-human study abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts) ; 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84 (7Suppl): Abstract nr CT088.