Abstract 7282: Comparing TEAD palmitoylation inhibitors with differential TEAD selectivity in combination efficacy with targeted therapies and in renal safety

Abstract Genetic alterations of the Hippo signaling pathway components resulting in YAP/TAZ activation have been reported in a variety of human malignancies. YAP/TAZ activation and functional requirement have also been linked to resistance to targeted therapies by providing the essential survival signal in drug-tolerant persister/dormant cells. As the main drivers for YAP/TAZ recruitment to chromatin, TEAD transcription factors are the major effectors of the Hippo-YAP/TAZ pathway involved in the regulation of cell proliferation, survival, and cell migration. There are four members in the TEAD family: TEAD1, TEAD2, TEAD3, and TEAD4. All four members have a conserved cysteine residue that gets auto-palmitoylated and a highly conserved central pocket in which the palmitate is buried. TEAD auto-palmitoylation is required for TEAD interaction with coactivator YAP/TAZ and transcriptional activity. We have discovered and developed highly potent and selective TEAD auto-palmitoylation inhibitors that interact directly with TEAD by occupying the central palmitate pocket, disrupt YAP/TAZ-TEAD protein interaction, suppress TEAD transcriptional activity, and selectively block NF2-deficient mesothelioma proliferation in vitro and inhibit NF2 mutant tumor growth in vivo. One of these compounds, VT3989, is being evaluated in an ongoing phase 1 clinical trial, where partial responses in mesothelioma patients have been demonstrated, showing for the first time that the Hippo pathway is druggable and that the Hippo pathway is now a validated target for cancer therapy. It remained a question, however, which TEAD members are more important and whether it would be safer and as efficacious to inhibit one TEAD member than multiple TEAD members. Thus, we utilized our TEAD inhibitors with differential TEAD selectivity to determine the importance of TEAD1 selectivity in anti-tumor efficacy and in renal safety. We evaluated the anti-tumor efficacy of several potent TEAD1-selective and pan-TEAD inhibitors in in vivo combination studies using EGFR mutant/KRAS mutant xenograft models. We found that TEAD1-selective TEAD palmitoylation inhibitors are less efficacious than pan-TEAD/multiple-TEAD inhibitors in combination studies with targeted therapies (as such EGFRi and KRASi). In 14-day/28-day rat studies, TEAD1-selective TEAD inhibitors also exhibited proteinuric nephropathy similar to that observed with pan-/multiple-TEAD inhibitors. Therefore, based on our findings, we can conclude that TEAD1-selective TEAD palmitoylation inhibitors can have similar on-target effect on kidneys as TEAD inhibitors with broader TEAD selectivity while having reduced anti-tumor efficacy and durability of response in combination with targeted therapies. Citation Format: Tracy T. Tang, Leonard Post. Comparing TEAD palmitoylation inhibitors with differential TEAD selectivity in combination efficacy with targeted therapies and in renal safety abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts) ; 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84 (6Suppl): Abstract nr 7282.