Discovery of YK-029A, a novel mutant EGFR inhibitor targeting both T790 M and exon 20 insertion mutations, as a treatment for NSCLC.

Although traditional EGFR-TKIs have advanced the treatment landscape of NSCLC with sensitive driver mutations (del19 or L858R), some NSCLC patients with EGFR exon 20 insertion mutations have been left with few effective therapies. The development of novel TKIs is still in progress. Herein, we describe the structure-guided design of a novel selective and orally bioavailable inhibitor, YK-029A, which could overcome both the T790 M mutations and exon 20 insertion of EGFR. YK-029A inhibited EGFR signaling, suppressed sensitive mutations and ex20ins of EGFR-driven cell proliferation, and was largely effective with oral administration in vivo. Furthermore, YK-029A exhibited significant antitumor activity in EGFRex20ins-driven patients-derived xenograft (PDX) models, preventing tumor progression or causing tumor regression at well-tolerated dosages. Based on the outcomes of preclinical efficacy and safety studies, YK-029A will enter phase Ⅲ clinical trials for the treatment of EGFRex20ins NSCLC.

Emission reductions, industrial competitiveness, and spillover effects under China's regional emission trading systems: Evidence from the iron and steel sector.

An emission trading system (ETS) has been consistently recognized as a promising instrument to stem massive carbon emissions from energy-intensive industries. However, it remains ambiguous whether the ETS can achieve emission mitigation without undermining economic activity in specific industries in emerging running markets. This study focuses on the impact of China's four independent ETS pilots on carbon emissions, industrial competitiveness, and spatial spillover effects in the iron and steel industry. With a synthetic control method for causal inference, we find that the achievement of emission reductions was generally accompanied by losses of competitiveness in the pilot regions. An exception to this trend was seen in the Guangdong pilot, where the aggregate emissions increased due to the incentivized output created by a specific benchmarking allocation approach. Despite impaired competitiveness, the ETS did not cause significant spatial spillovers, which alleviates concerns about potential carbon leakage under unilateral climate regulation. Our findings could enlighten subsequent sector-specific assessments of the effectiveness of ETSs and are also valuable to policymakers in and outside China now considering ETSs.

Orderly retire China's coal-fired power capacity via capacity payments to support renewable energy expansion.

The energy-only-market implemented in China cannot strongly support large-scale renewable energy expansion because the renewable energy expansion may disorderly phase out non-renewable power capacity. However, non-renewable power capacity, particularly the coal-fired power capacity in China, can provide vital power system adequacy needed by renewable energy expansion. We introduce capacity payments to orderly retire current coal-fired power capacity by transforming some of it into reserve capacity in order to support renewable energy expansion. Using generation and transmission expansion results from the SWITCH-China model, this paper proposes an orderly retirement path based on the assumption of implementing capacity payments. Our results show that roughly 100-200 gigawatts (GW) of coal-fired power capacity can continue to serve through 2050, and most of it is used as reserve capacity. Capacity payments of 400-700 billion yuan are needed to achieve this retirement path, and a higher adequacy requirement needs higher payments.

The new CORSIA baseline has limited motivation to promote the green recovery of global aviation.

The Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) is the first programme to tackle carbon dioxide (CO2) emissions from a single industry at the global level, to realize the carbon-neutral growth of international flights from 2020 onwards. However, the COVID-19 pandemic has caused a drastic decline in the global aviation industry. The International Civil Aviation Organization (ICAO) has adjusted the CORSIA by removing 2020 emissions from the baseline, which now will only be based on 2019 emissions. We estimate that the total carbon dioxide (CO2) emissions from global international flights decreased by 70 % from February to July 2020 compared to those in 2019. Our analysis suggests that the annual CO2 emissions from international flights during the pilot stage of CORSIA (2021-2023) will be far below the revised baseline even if the global aviation industry could embrace an optimistic recovery. The major airline companies will have very limited motivations due to the CORSIA scheme to implement mitigation actions proactively. Therefore, more progressive actions are needed to align the industry recovery of global aviation and climate change mitigation during the post-COVID-19 period.

China's pilot emissions trading schemes and competitiveness: An empirical analysis of the provincial industrial sub-sectors.

China's economic development has entered a "new normal" stage where economic growth has slowed down. In this context, China's local authorities and industry circles are particularly concerned about the impact of emissions trading scheme (ETS), China's first major market-based approach to control greenhouse gas emissions, on competitiveness. This paper contributes to the thin empirical studies on this issue from the perspective of China's provincial industrial sub-sectors. We divide the industry of each province into 37 sub-sectors and screen the actual industrial sub-sector coverage of China's pilot ETSs. Taking advantage of the rich information of sub-sector characteristics and the longitudinal structure of our dataset over 2005-2015, we use a combination of propensity score matching technique and difference-in-difference models to analyze the impact of China's pilot ETSs on gross industrial output value (GIOV) and employment. Empirical results indicate that China's pilot ETSs have exerted a negative impact on the GIOV, and production cut is still the major approach to achieve carbon emission reductions. We also find China's pilot ETSs have led to a significant decrease in employment of the covered industrial sub-sectors. Several robustness checks confirm our findings. Further, our discussions suggest that in the short term, China's pilot ETSs have not promoted the "decoupling" of carbon emissions and economic outputs in industrial sub-sectors. While achieving carbon emission reductions, the pilot ETSs have failed to avoid a negative impact on competitiveness. Lastly, we suggest that competent authorities should prudently tailor the quota allocation methods according to sectorial conditions and consider setting up compensation measures, and covered enterprises should incorporate low-carbon development concept and address the challenges proactively from the long run.

Biological and Structural Characterization of Rotamers of C-C Chemokine Receptor Type 5 (CCR5) Inhibitor GSK214096.

We recently reported the discovery of preclinical CCR5 inhibitor GSK214096, 1 (J. Med. Chem. 2011, 54, 756). Detailed characterization of 1 revealed that it exists as a mixture of four separable atropisomers A-D. The two slow-interconverting pairs of rotamers A + B and C + D were separated and further characterized. HIV and CCR5-mediated chemotaxis data strongly suggest that the antiviral potency of 1 is due to rotamers A + B and not C + D. Furthermore, integrated UV, vibrational circular dichroism VCD and computational approach allowed to determine the M chirality in C + D (and P chirality in A + B). These findings imply additional avenues to be pursued toward new CCR5 antagonists.

Novel spiroketal pyrrolidine GSK2336805 potently inhibits key hepatitis C virus genotype 1b mutants: from lead to clinical compound.

Rapid clinical progress of hepatitis C virus (HCV) replication inhibitors, including these selecting for resistance in the NS5A region (NS5A inhibitors), promises to revolutionize HCV treatment. Herein, we describe our explorations of diverse spiropyrrolidine motifs in novel NS5A inhibitors and a proposed interaction model. We discovered that the 1,4-dioxa-7-azaspiro[4.4]nonane motif in inhibitor 41H (GSK2236805) supported high potency against genotypes 1a and 1b as well as in genotype 1b L31V and Y93H mutants. Consistent with this, 41H potently suppressed HCV RNA in the 20-day RNA reduction assay. Pharmacokinetic and safety data supported further progression of 41H to the clinic.

Synthesis and antiviral activity of novel HCV NS3 protease inhibitors with P4 capping groups.

We have synthesized and evaluated a series of novel HCV NS3 protease inhibitors with various P4 capping groups, which include urea, carbamate, methoxy-carboxamide, cyclic carbamate and amide, pyruvic amide, oxamate, oxalamide and cyanoguanidine. Most of these compounds are remarkably potent, exhibiting single-digit to sub-nanomolar activity in the enzyme assay and cell-based replicon assay. Selected compounds were also evaluated in the protease-inhibitor-resistant mutant transient replicon assay, and they were found to show quite different potency profiles against a panel of HCV protease-inhibitor-resistant mutants.

Discovery of novel urea-based hepatitis C protease inhibitors with high potency against protease-inhibitor-resistant mutants.

The macrocyclic urea 2, a byproduct in the synthesis of benzoxaborole 1, was identified to be a novel and potent HCV protease inhibitor. We further explored this motif by synthesizing additional urea-based inhibitors and by characterizing them in replicase HCV protease-resistant mutants assay. Several compounds, exemplified by 12, were found to be more potent in HCV replicon assays than leading second generation inhibitors such as danoprevir and TMC-435350. Additionally, following oral administration, inhibitor 12 was found in rat liver in significantly higher concentrations than those reported for both danoprevir and TMC-435350, suggesting that inhibitor 12 has the combination of anti-HCV and pharmacokinetic properties that warrants further development of this series.

Discovery of novel P3-oxo inhibitor of hepatitis C virus NS3/4A serine protease.

A novel series of P3 oxo-modified macrocyclic hepatitis C virus NS3/4A serine protease inhibitor was designed, synthesized and biologically evaluated. The hydroxy-substituted inhibitor 10 demonstrated high potency in genotype 1a and 1b replicon and in the panel of HCV protease mutants. Interestingly, the t-butyl carbonate analog 9c, while not the most potent one in this series, exhibited a virtually flat potency profile in the panel of HCV protease mutants, thus providing opportunity for further optimization.

Discovery of a novel series of cyclic urea as potent CCR5 antagonists.

A novel series of cyclic urea-based CCR5 antagonists was designed aiming to resolve instability issue in the fasted simulated intestinal fluid (FSIF) associated with the acyclic urea moiety in 1. This class of CCR5 compounds demonstrated high antiviral activities against HIV-1 infection in both HOS and PBL assays. Further evaluation of these compounds indicated that 16-R not only substantially enhanced its stability, but also exhibited excellent pharmacokinetics properties.

Discovery of novel pyridyl carboxamides as potent CCR5 antagonists and optimization of their pharmacokinetic profile in rats.

A novel series of pyridyl carboxamide-based CCR5 inhibitors was designed, synthesized, and demonstrated to be highly potent against HIV-1 infection in both HOS and PBL assays. Attempts to evaluate this series of compounds in a rat PK model revealed its instability in rat plasma. A hypothesis for this liability was proposed, and strategies to overcome this issue were pursued, leading to discovery of highly potent 40 and 41, which featured dramatically improved rat PK profiles.

Novel 4,4-disubstituted piperidine-based C-C chemokine receptor-5 inhibitors with high potency against human immunodeficiency virus-1 and an improved human ether-a-go-go related gene (hERG) profile.

We recently described ( J. Med. Chem. 2008 , 51 , 6538 - 6546 ) a novel class of CCR5 antagonists with strong anti-HIV potency. Herein, we detail SAR converting leads 1 and 2 to druglike molecules. The pivotal structural motif enabling this transition was the secondary sulfonamide substituent. Further fine-tuning of the substituent pattern in the sulfonamide paved the way to enhancing potency and bioavailability and minimizing hERG inhibition, resulting in discovery of clinical compound 122 (GSK163929).

Synthesis and SAR of acyclic HCV NS3 protease inhibitors with novel P4-benzoxaborole moieties.

We have synthesized and evaluated a new series of acyclic P4-benzoxaborole-based HCV NS3 protease inhibitors. Structure-activity relationships were investigated, leading to the identification of compounds 5g and 17 with low nanomolar potency in the enzymatic and cell-based replicon assay. The linker-truncated compound 5j was found to exhibit improved absorption and oral bioavailability in rats, suggesting that further reduction of molecular weight and polar surface area could result in improved drug-like properties of this novel series.

Synthesis and evaluation of 2-phenyl-1,4-butanediamine-based CCR5 antagonists for the treatment of HIV-1.

We describe the synthesis and potency of a novel series of N-substituted 2-phenyl- and 2-methyl-2-phenyl-1,4-diaminobutane- based CCR5 antagonists. Compounds 7a and 12f were found to be potent in anti-HIV assays and bioavailable in the low-dose rat PK model.

Discovery of N-benzyl-N'-(4-pipyridinyl)urea CCR5 antagonists as anti-HIV-1 agents (I): optimization of the amine portion.

Several series of carbamate, urea and carboxamide-based CCR5 antagonists have been discovered via optimizations at the amine portion of lead compound 2. All compounds were evaluated for their antiviral activities. Lead urea 29 showed good pharmacokinetic properties, justifying further development of this series.

Discovery of N-benzyl-N'-(4-pipyridinyl)urea CCR5 antagonists as anti-HIV-1 agents (II): modification of the acyl portion.

Modification of the acyl moiety in the CCR5 lead molecule 2 led to identification of several new classes of CCR5 antagonists. Antiviral activity and pharmacokinetic properties of the synthesized compounds were evaluated. Structure-activity relationship (SAR) derived from these studies further guided the optimization efforts, ultimately leading to the discovery of 36 with an acceptable drug-like profile.

Synthesis of new acylsulfamoyl benzoxaboroles as potent inhibitors of HCV NS3 protease.

HCV NS3/4A serine protease is essential for the replication of the HCV virus and has been a clinically validated target. A series of HCV NS3/4A protease inhibitors containing a novel acylsulfamoyl benzoxaborole moiety at the P1' region was synthesized and evaluated. The resulting P1-P3 and P2-P4 macrocyclic inhibitors exhibited sub-nanomolar potency in the enzymatic assay and low nanomolar activity in the cell-based replicon assay. The in vivo PK evaluations of selected compounds are also described.

Synthesis and biological evaluations of P4-benzoxaborole-substituted macrocyclic inhibitors of HCV NS3 protease.

We disclose here a series of P4-benzoxaborole-substituted macrocyclic HCV protease inhibitors. These inhibitors are potent against HCV NS3 protease, their anti-HCV replicon potencies are largely impacted by substitutions on benzoxaborole ring system and P2∗ groups. P2∗ 2-thiazole-isoquinoline provides best replicon potency. The in vitro SAR studies and in vivo PK evaluations of selected compounds are described herein.