Abstract LB319: IAG933, a selective and orally efficacious YAP1/WWTR1(TAZ)-panTEAD protein-protein interaction inhibitor with pre-clinical activity in monotherapy and combinations

Abstract The YAP-TEAD protein-protein interaction (PPI) is a critical event known to mediate YAP oncogenic functions downstream of the Hippo pathway. Current advanced pharmacological agents which aim at inhibiting YAP-TEAD oncogenic function do so by engaging into the lipid pocket of TEAD. Thereby the consequences of a direct pharmacological disruption of the interface of YAP and TEADs remain unexplored. Here we report the identification of IAG933, the first molecule able to potently and directly disrupt the YAP/TAZ-TEADs PPI with suitable properties to enter in clinical trial. The path to drug discovery was established by structure-based optimization of a truncated natural YAP peptide allowing the pharmacophore mapping of TEAD coil binding site. Based on in silico screening, validated hit was optimized using structure- and property-based lead optimization yielding IAG933, whose chemical structure will be for the first time disclosed here. Biochemical and cellular assays demonstrate that IAG933 specifically abrogates the interaction between YAP/TAZ coactivators and all four TEAD isoforms, thus selectively inhibiting TEAD-driven transcriptional activity and inducing anti-cancer effects. At the epigenome level, YAP eviction from chromatin was observed upon treatment with IAG933, while leaving TEADs genomic occupancy unaffected. Concomitantly, engagement of co-repressor VGLL4 translated to a decrease in enhancer activity with rapid and progressive changes in transcription of Hippo target genes. In preclinical experiments, IAG933 linear pharmacokinetics was consistent with dose proportional TEAD transcriptional inhibition and anti-tumor efficacy in xenograft and primary-tumor derived malignant pleural mesothelioma models. Daily treatment with IAG933 elicited complete tumor regression in the MSTO-211H xenograft model at well-tolerated doses. In line with the current clinical strategy for IAG933, robust anti-tumor efficacy in cancer models bearing NF2 loss of function or expressing TAZ-fusions was observed. Moreover, we provide evidence for combination benefits of IAG933 with several MAPK/KRAS inhibitors, both in vitro and in vivo, in non-Hippo altered models including lung, pancreatic and colorectal cancer. Overall, our results provide a rationale of progressing IAG933 as a monotherapy in patients with Hippo-mutated cancers, and as a combination partner in MAPK-dependent cancers, with the potential to treat patient populations of high unmet medical need. Citation Format: Tobias Schmelzle, Emilie Chapeau, Daniel Bauer, Patrick Chene, Jason Faris, Cesar Fernandez, Pascal Furet, Giorgio Galli, Jiachang Gong, Stephanie Harlfinger, Francesco Hofmann, Eloisa Jimenez Nunez, Joerg Kallen, Thanos Mourikis, Laurent Sansregret, Paulo Santos, Clemens Scheufler, Holger Sellner, Markus Voegtle, Markus Wartmann, Peter Wessels, Frederic Zecri, Nicolas Soldermann. IAG933, a selective and orally efficacious YAP1/WWTR1(TAZ)-panTEAD protein-protein interaction inhibitor with pre-clinical activity in monotherapy and combinations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB319.