Synthesis, activity, and their relationships of 2,4-diaminonicotinamide derivatives as EGFR inhibitors targeting C797S mutation.

The C797S mutation is one of the major factors behind resistance to the third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors. Herein, we describe the discovery of the 2,4-diaminonicotinamide derivative 5j, which shows potent inhibitory activity against EGFR del19/T790M/C797S and L858R/T790M/C797S. We also report the structure-activity relationship of the 2,4-diaminonicotinamide derivatives and the co-crystal structure of 5j and EGFR del19/T790M/C797S.

Discovery of a potent, selective, and orally available EGFR C797S mutant inhibitor (DS06652923) with in vivo antitumor activity.

The C797S mutation is one of the major factors behind resistance to the third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). Herein, we describe the discovery of DS06652923, a novel, potent, and orally available EGFR-triple-mutant inhibitor. Through scaffold hopping from the previously reported nicotinamide derivative, a novel biaryl scaffold was obtained. The potency was successfully enhanced by the introduction of basic substituents based on analysis of the docking study results. In addition, the difluoromethoxy group on the pyrazole ring improved the kinase selectivity by inducing steric clash with the other kinases. The most optimized compound, DS06652923, achieved tumor regression in the Ba/F3 allograft model upon its oral administration.

Discovery of EP300/CBP histone acetyltransferase inhibitors through scaffold hopping of 1,4-oxazepane ring.

EP300 and its paralog CBP play an important role in post-translational modification as histone acetyltransferases (HATs). EP300/CBP inhibition has been gaining attention as an anticancer treatment target in recent years. Herein, we describe the identification of a novel, highly selective EP300/CBP inhibitor, compound 11 (DS17701585), by scaffold hopping and structure-based optimization of a high-throughput screening hit 1. Compound 11 (DS17701585) shows dose-dependent inhibition of SRY-box transcription factor 2 (SOX2) mRNA expression in a human lung squamous cell carcinoma cell line LK2-xenografted mouse model.

Discovery of DS-9300: A Highly Potent, Selective, and Once-Daily Oral EP300/CBP Histone Acetyltransferase Inhibitor.

Histone acetylation is a post-translational modification of histones that is catalyzed by histone acetyltransferases (HATs) and plays an essential role in cellular processes. The HAT domain of EP300/CBP has recently emerged as a potential drug target for cancer therapy. Here, we describe the identification of the novel, highly potent, and selective EP300/CBP HAT inhibitor DS-9300. Our optimization efforts using a structure-based drug design approach based on the cocrystal structures of the EP300 HAT domain in complex with compounds 2 and 3 led to the identification of compounds possessing low-nanomolar EP300 HAT inhibitory potency and the ability to inhibit cellular acetylation of histone H3K27. Optimization of the pharmacokinetic properties in this series resulted in compounds with excellent oral systemic exposure, and once-daily oral administration of 16 (DS-9300) demonstrated potent antitumor effects in a castrated VCaP xenograft mouse model without significant body weight loss.