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Ataxia telangiectasia and RAD3-related kinase (ATR) is one of the key phosphatidylinositol 3-kinase-related kinase family members important for DNA damage response and repair pathways. Targeting ATR kinase for potential cancer therapy has attracted a great deal of attention to both pharmaceutical industries and academic community.This article surveys the patents published since 2014 aiming to analyze the structural features of scaffolds and the patent space. It also discusses the recent clinical developments and provides perspectives on the challenges and the future directions.ATR kinase appears to be a viable drug target for anticancer therapy. Similar to DNA-PK inhibitors, the clinical investigation of an ATRi employs both monotherapy and combination strategy. In the combination strategy, an ATRi is typically combined with a radiation or a targeted drug such as chemotherapy agent poly (ADP-ribose) polymerase (PARP) inhibitor, etc. Diverse structures comprising different scaffolds from mono-heteroaryl to bicyclic heteroaryl to tricyclic heteroaryl to macrocycle are capable of achieving good ATR inhibitory activity and good ATR selectivity over other closely related enzymes. There are eight ATR inhibitors currently being evaluated in clinics, with the hope to get approval in the near future.

Protein arginine methyltransferases (PRMTs), enzymes catalyzing the methylation of target proteins, play an essential role in maintaining functional homeostasis in normal physiology. Aberrant expressions and enhanced enzymatic activities of PRMTs have been closely associated with pathological states such as cancer, inflammatory, immune, metabolic, and neurodegenerative diseases. Therefore, the development of inhibitors targeting PRMTs has attracted a great deal of attention in both pharmaceutical industries and academic community. This review focuses on the small-molecule inhibitors targeting PRMTs in cancer therapy in the patents published since 2019. The recent clinical development is also discussed here. In recent years, the discovery of small-molecule PRMT inhibitors, especially PRMT5 inhibitors has become a rapidly expanding research area for cancer therapy. Although a number of potent PRMT inhibitors with different chemical scaffolds have been developed and nine of them have entered into clinical trials, their scaffolds are relatively less diverse. Sub-type selectivity should be considered in drug discovery as nonselective inhibition of PRMTs may cause undesirable pharmacological effects. Hence, the development of new effective inhibitors with isoform-specific and tumor-biased distributions remains an important area for further studies.