New drug approvals for 2022: Synthesis and clinical applications

A comprehensive review of new small molecule drugs approved by the FDA in 2022: Advance and prospect

In 2022, the U.S. Food and Drug Administration approved a total of 16 marketing applications for small molecule drugs, which not only provided dominant scaffolds but also introduced novel mechanisms of action and clinical indications. The successful cases provide valuable information for optimizing efficacy and enhancing pharmacokinetic properties through strategies like macrocyclization, bioequivalent group utilization, prodrug synthesis, and conformation restriction. Therefore, gaining an in-depth understanding of the design principles and strategies underlying these drugs will greatly facilitate the development of new therapeutic agents. This review focuses on the research and development process of these newly approved small molecule drugs including drug design, structural modification, and improvement of pharmacokinetic properties to inspire future research in this field.

Discovery of novel pyrazolo[1,5-a]pyrimidine derivatives as potent reversal agents against ABCB1-mediated multidrug resistance

The P-glycoprotein (ABCB1)-mediated multidrug resistance (MDR) has emerged as a significant impediment to the efficacy of cancer chemotherapy in clinical therapy, which could promote the development of effective agents for MDR reversal. In this work, we reported the exploration of novel pyrazolo [1,5-a]pyrimidine derivatives as potent reversal agents capable of enhancing the sensitivity of ABCB1-mediated MDR MCF-7/ADR cells to paclitaxel (PTX). Among them, compound 16q remarkably increased the sensitivity of MCF-7/ADR cells to PTX at 5 μM (IC50 = 27.00 nM, RF = 247.40) and 10 μM (IC50 = 10.07 nM, RF = 663.44). Compound 16q could effectively bind and stabilize ABCB1, and does not affect the expression and subcellular localization of ABCB1 in MCF-7/ADR cells. Compound 16q inhibited the function of ABCB1, thereby increasing PTX accumulation, and interrupting the accumulation and efflux of the ABCB1-mediated Rh123, thus resulting in exhibiting good reversal effects. In addition, due to the potent reversal effects of compound 16q, the abilities of PTX to inhibit tubulin depolymerization, and induce cell cycle arrest and apoptosis in MCF-7/ADR cells under low-dose conditions were restored. These results indicate that compound 16q might be a promising potent reversal agent capable of revising ABCB1-mediated MDR, and pyrazolo [1,5-a]pyrimidine might represent a novel scaffold for the discovery of new ABCB1-mediated MDR reversal agents.

A comprehensive review of small molecule drugs approved by the FDA in 2023: Advances and prospects

In 2023, the U.S. Food and Drug Administration has approved 55 novel medications, consisting of 17 biologics license applications and 38 new molecular entities. Although the biologics license applications including antibody and enzyme replacement therapy set a historical record, the new molecular entities comprising small molecule drugs, diagnostic agent, RNA interference therapy and biomacromolecular peptide still account for over 50 % of the newly approved medications. The novel and privileged scaffolds derived from drugs, active molecules and natural products are consistently associated with the discovery of new mechanisms, the expansion of clinical indications and the reduction of side effects. Moreover, the structural modifications based on the promising scaffolds can provide the clinical candidates with the improved biological activities, bypass the patent protection and greatly shorten the period of new drug discovery. Therefore, conducting an appraisal of drug approval experience and related information will expedite the identification of more potent drug molecules. In this review, we comprehensively summarized the pertinent information encompassing the clinical application, mechanism, elegant design and development processes of 28 small molecule drugs, and expected to provide the promising structural basis and design inspiration for pharmaceutical chemists.

Synthesis and biological evaluation of 4-phenyl-5-quinolinyl substituted isoxazole analogues as potent cytotoxic and tubulin polymerization inhibitors against ESCC

The identification of chemically different inhibitors that target the colchicine site of tubulin is still of great value for cancer treatment. Combretastatin A-4(CA-4), a naturally occurring colchicine-site binder characterized by its structural simplicity and biological activity, has served as a structural blueprint for the development of novel analogues with improved safety and therapeutic efficacy. In this study, a library of forty-eight 4-phenyl-5-quinolinyl substituted triazole, pyrazole or isoxazole analouges of CA-4, were synthesized and evaluated for their cytotoxicity against Esophageal Squamous Cell Carcinoma (ESCC) cell lines. Compound C11, which features a 2-methyl substitution at the quinoline and carries an isoxazole ring, emerged as the most promising, with 48 h IC50s of less than 20 nmol/L against two ESCC cell lines. The findings from EBI competitive assay, CETA, and in vitro tubulin polymerization assay of C11 are consistent with those of the positive control colchicine, demonstrating the clear affinity of compound C11 to the colchicine binding site. The subsequent cellular-based mechanism studies revealed that C11 significantly inhibited ESCC cell proliferation, arrested cell cycle at the M phase, induced apoptosis, and impeded migration. Experiments conducted in vivo further confirmed that C11 effectively suppressed the growth of ESCC without showing any toxicity towards the selected animal species. Overall, our research suggests that the tubulin polymerization inhibitor incorporating quinoline and the isoxazole ring may deserve consideration for cancer therapy.

The mechanism of action and chemical synthesis of FDA newly approved drug molecules

In 2023, the U.S. Food and Drug Administration has approved 29 small molecule drugs. These newly approved small molecule drugs possess the distinct scaffolds, thereby exhibiting diverse mechanisms of action and binding modalities. Moreover, the marketed drugs have always been an important source of new drug development and creative inspiration, thereby fostering analogous endeavors in drug discovery that potentially extend to the diverse clinical indications. Therefore, conducting a comprehensive evaluation of drug approval experience and associated information will facilitate the expedited identification of highly potent drug molecules. In this review, we comprehensively summarized the relevant information regarding the clinical applications, mechanisms of action and chemical synthesis of 29 small molecule drugs, with the aim of providing a promising structural basis and design inspiration for pharmaceutical chemists.

The recent advance and prospect of poly(ADP-ribose) polymerase inhibitors for the treatment of cancer

Chemotherapies are commonly used in cancer therapy, their applications are limited to low specificity, severe adverse reactions, and long-term medication-induced drug resistance. Poly(ADP-ribose) polymerase (PARP) inhibitors are a novel class of antitumor drugs developed to solve these intractable problems based on the mechanism of DNA damage repair, which have been widely applied in the treatment of ovarian cancer, breast cancer, and other cancers through inducing synthetic lethal effect and trapping PARP-DNA complex in BRCA gene mutated cancer cells. In recent years, PARP inhibitors have been widely used in combination with various first-line chemotherapy drugs, targeted drugs and immune checkpoint inhibitors to expand the scope of clinical application. However, the intricate mechanisms underlying the drug resistance to PARP inhibitors, including the restoration of homologous recombination, stabilization of DNA replication forks, overexpression of drug efflux protein, and epigenetic modifications pose great challenges and desirability in the development of novel PARP inhibitors. In this review, we will focus on the mechanism, structure-activity relationship, and multidrug resistance associated with the representative PARP inhibitors. Furthermore, we aim to provide insights into the development prospects and emerging trends to offer guidance for the clinical application and inspiration for the development of novel PARP inhibitors and degraders.

Sulfone Electrophiles in Cross-Electrophile Coupling: Nickel-Catalyzed Difluoromethylation of Aryl Bromides

Fluoroalkyl fragments have played a critical role in the design of pharmaceutical and agrochemical molecules in recent years due to the enhanced biological properties of fluorinated molecules compared to their non-fluorinated analogues. Despite the potential advantages conferred by incorporating a difluoromethyl group in organic compounds, industrial adoption of difluoromethylation methods lags behind fluorination and trifluoromethylation. This is due in part to challenges in applying common difluoromethyl sources towards industrial applications. We report here the nickel-catalyzed cross-electrophile coupling of (hetero)aryl bromides with difluoromethyl 2-pyridyl sulfone, a sustainably sourced, crystalline difluoromethylation reagent. The scope of this reaction is demonstrated with 24 examples (67 ± 16% average yield) including a diverse array of heteroaryl bromides and precursors to difluoromethyl-containing preclinical pharmaceuticals. This reaction can be applied to small-scale parallel synthesis and benchtop scale-up under mild conditions. As sulfone reagents are uncommon electrophiles in cross-electrophile coupling, the mechanism of this process was investigated. Studies confirmed the formation of •CF2H instead of difluorocarbene. A series of modified difluoromethyl sulfones revealed that sulfone reactivity does not correlate exclusively with reduction potential and that coordination of cations or nickel to the pyridyl group is essential to reactivity, setting out parameters for matching the reactivity of sulfones in cross-electrophile coupling.

Annual review of PROTAC degraders as anticancer agents in 2022

Following nearly two decades of development, significant advancements have been achieved in PROTAC technology. As of the end of 2022, more than 20 drugs have entered clinical trials, with ARV-471 targeting estrogen receptor (ER) showing remarkable progress by entering phase III clinical studies. In 2022, significant progress has been made on multiple targets. The first reversible covalent degrader designed to target the KRASG12C mutant protein, based on cyclopropionamide, has been reported. Additionally, the activity HDCA1 degrader surpassed submicromolar levels during the same year. A novel FEM1B covalent ligand called EN106 was also discovered, expanding the range of available ligands. Furthermore, the first PROTAC drug targeting SOS1 was reported. Additionally, the first-in-class degraders that specifically target BRD4 isoforms (BRD4 L and BRD4 S) have recently been reported, providing a valuable tool for further investigating the biological functions of these isoforms. Lastly, a breakthrough was also achieved with the first degrader targeting both CDK9 and Cyclin T1. In this review, we aimed to update the PROTAC degraders as potential anticancer agents covering articles published in 2022. The design strategies, degradation effects, and anticancer activities were highlighted, which might provide an updated sight to develop novel PROTAC degraders with great potential as anticancer agents as well as favorable drug-like properties.

Design, synthesis and biological evaluation of 1,2,3-triazole benzothiazole derivatives as tubulin polymerization inhibitors with potent anti-esophageal cancer activities

In this work, we utilized the molecular hybridization strategy to design and synthesize novel 1,2,3-triazole benzothiazole derivatives K1-26. The antiproliferative activities against MGC-803, Kyse30 and HCT-116 cells were explored, and their structure-activity relationship were preliminarily conducted and summarized. Among them, compound K18, exhibited the strongest proliferation inhibitory activity, with esophageal cancer cells Kyse30 and EC-109 being the most sensitive to its effects (IC50 values were 0.042 and 0.038 μM, respectively). Compound K18 effectively inhibited tubulin polymerization (IC50 = 0.446 μM), thereby hindering tubulin polymerize into filamentous microtubules in Kyse30 and EC-109 cells. Additionally, compound K18 induced the degradation of oncogenic protein YAP via the UPS pathway. Based on these dual molecular-level effects, compound K18 could induce G2/M phase arrest and cell apoptosis in Kyse30 and EC-109 cells, as well as regulate the expression levels of cell cycle and apoptosis-related proteins. In summary, our findings highlight a novel 1,2,3-triazole benzothiazole derivative K18, which possesses significant potential for treating esophageal cancers.

Discovery of novel coumarin-based derivatives as inhibitors of tubulin polymerization targeting the colchicine binding site with potent anti-gastric cancer activities

In this work, a series of novel coumarin-based derivatives were designed and synthesized as tubulin polymerization inhibitors targeting the colchicine binding site, and their antiproliferative activities against MGC-803, HCT-116 and KYSE30 cells were evaluated. Among them, the compound I-3 (MY-1442) bearing a 6-methoxy-1,2,3,4-tetrahydroquinoline group exhibited most potent inhibitory activities on MGC-803 (IC50 = 0.034 μM), HCT-116 (IC50 = 0.081 μM) and KYSE30 cells (IC50 = 0.19 μM). Further mechanism studies demonstrated that compound I-3 (MY-1442) could directly bind to the colchicine binding site of β-tubulin to inhibit tubulin polymerization and microtubules at the cellular level. The results of molecular docking indicated there were well binding interactions between compound I-3 (MY-1442) and the colchicine binding site of β-tubulin. Compound I-3 (MY-1442) also exhibited effective anti-proliferation, pro-apoptosis, and anti-migration abilities against gastric cancer cells MGC-803. Additionally, compound I-3 (MY-1442) could regulate the expression of cell cycle- and apoptosis-related proteins. Importantly, compound I-3 (MY-1442) could significantly inhibit tumor growth in the MGC-803 xenograft tumor model with a TGI rate of 65.5 % at 30 mg/kg/day. Taken together, this work suggested that the coumarin skeleton exhibited great potential to be a key pharmacophore of tubulin polymerization inhibitors for the discovery of anticancer agents.

Unveiling terahertz wave stress effects and mechanisms in Pinellia ternata: Challenges, insights, and future directions

This review aims to elucidate the intricate effects and mechanisms of terahertz (THz) wave stress on Pinellia ternata, providing valuable insights into plant responses. The primary objective is to highlight the imperative for future research dedicated to comprehending THz wave impacts across plant structures, with a specific focus on the molecular intricacies governing root system structure and function, from shoots to roots. Notably, this review highlights the accelerated plant growth induced by THz waves, especially in conjunction with other environmental stressors, and the subsequent alterations in cellular homeostasis, resulting in the generation of reactive oxygen species (ROS) and an increase in brassinosteroids. Brassinosteroids are explored for their dual role as toxic by-products of stress metabolism and vital signal transduction molecules in plant responses to abiotic stresses. The paper further investigates the spatio-temporal regulation and long-distance transport of phytohormones, including growth hormone, cytokinin, and abscisic acid (ABA), which significantly influence the growth and development of P. ternata under THz wave stress. With a comprehensive review of Reactive oxygen species (ROS) and Brassinosteroid Insensitive (BRI) homeostasis and signalling under THz wave stress, the article elucidates the current understanding of BRI involvement in stress perception, stress signalling, and domestication response regulation. Additionally, it underscores the importance of spatio-temporal regulation and long-distance transport of key plant hormones, such as growth hormone, cytokinin, and ABA, in determining root growth and development under THz wave stress. The study of how plants perceive and respond to environmental stresses holds fundamental biological significance, and enhancing plant stress tolerance is crucial for promoting sustainable agricultural practices and mitigating the environmental burdens associated with low-tolerance crop cultivation.

Design, synthesis and biological evaluation of novel 2,4-diaminopyrimidine cinnamyl derivatives as inhibitors of FAK with potent anti-gastric cancer activities

In this study, twenty-one novel 2,4-diaminopyrimidine cinnamyl derivatives as inhibitors targeting FAK were designed and synthesized based on the structure of TAE-226, and the inhibitory effects of these compounds on both the FAK enzyme and three cancer cell lines (MGC-803, HCT-116, and KYSE30) were investigated. Among them, compound 12s displayed potent inhibitory potency on FAK (IC50 = 47 nM), and demonstrated more significant antiproliferative activities in MGC-803, HCT-116 and KYSE30 cells (IC50 values were 0.24, 0.45 and 0.44 μM, respectively) compared to TAE-226. Furthermore, compound 12s significantly inhibited FAK activation leading to the negative regulation of FAK-related signaling pathways such as AKT/mTOR and MAPK signaling pathways. Molecular docking study suggested that compound 12s could well occupy the ATP-binding pocket site of FAK similar to TAE-226. In addition, compound 12s also efficiently inhibited the proliferation, induced apoptosis and cellular senescence in MGC-803 cells. In conclusion, compound 12s emerges a potent FAK inhibitor that could exert potent inhibitory activity against gastric cancer cells.

A review of progress in o-aminobenzamide-based HDAC inhibitors with dual targeting capabilities for cancer therapy

Histone deacetylases, as a new class of anticancer targets, could maintain homeostasis by catalyzing histone deacetylation and play important roles in regulating the expression of target genes. Due to the fact that simultaneous intervention with dual tumor related targets could improve treatment effects, researches on innovative design of dual-target drugs are underway. HDAC is known as a "sensitizer" for the synergistic effects with other anticancer-target drugs because of its flexible structure design. The synergistic effects of HDAC inhibitor and other target inhibitors usually show enhanced inhibitory effects on tumor cells, and also provide new strategies to overcome multidrug resistance. Many research groups have reported that simultaneously inhibiting HDAC and other targets, such as tubulin, EGFR, could enhance the therapeutic effects. The o-aminobenzamide group is often used as a ZBG group in the design of HDAC inhibitors with potent antitumor effects. Given the prolonged inhibitory effects and reduced toxic side effects of HDAC inhibitors using o-aminobenzamide as the ZBG group, the o-aminobenzamide group is expected to become a more promising alternative to hydroxamic acid. In fact, o-aminobenzamide-based dual inhibitors of HDAC with different chemical structures have been extensively prepared and reported with synergistic and enhanced anti-tumor effects. In this work, we first time reviewed the rational design, molecular docking, inhibitory activities and potential application of o-aminobenzamide-based HDAC inhibitors with dual targeting capabilities in cancer therapy, which might provide a reference for developing new and more effective anticancer drugs.