Discovery of a Promising CBP/p300 Degrader XYD129 for the Treatment of Acute Myeloid Leukemia.

The epigenetic target CREB (cyclic-AMP responsive element binding protein) binding protein (CBP) and its homologue p300 were promising therapeutic targets for the treatment of acute myeloid leukemia (AML). Herein, we report the design, synthesis, and evaluation of a class of CBP/p300 PROTAC degraders based on our previously reported highly potent and selective CBP/p300 inhibitor 5. Among the compounds synthesized, 11c (XYD129) demonstrated high potency and formed a ternary complex between CBP/p300 and CRBN (AlphaScreen). The compound effectively degraded CBP/p300 proteins and exhibited greater inhibition of growth in acute leukemia cell lines compared to its parent compound 5. Furthermore, 11c demonstrated significant inhibition of tumor growth in a MOLM-16 xenograft model (TGI = 60%) at tolerated dose schedules. Our findings suggest that 11c is a promising lead compound for the treatment of AML.

Discovery of Highly Potent and Efficient CBP/p300 Degraders with Strong In Vivo Antitumor Activity.

The transcriptional coactivator cAMP response element binding protein (CREB)-binding protein (CBP) and its homologue p300 have emerged as attractive therapeutic targets for human cancers such as acute myeloid leukemia (AML). Herein, we report the design, synthesis, and biological evaluation of a series of cereblon (CRBN)-recruiting CBP/p300 proteolysis targeting chimeras (PROTACs) based on the inhibitor CCS1477. The representative compounds 14g (XYD190) and 14h (XYD198) potently inhibited the growth of AML cells with low nanomolar IC50 values and effectively degraded CBP and p300 proteins in a concentration- and time-dependent manner. Mechanistic studies confirmed that 14g and 14h can selectively bind to CBP/p300 bromodomains and induce CBP and p300 degradation in bromodomain family proteins in a CRBN- and proteasome-dependent manner. 14g and 14h displayed remarkable antitumor efficacy in the MV4;11 xenograft model (TGI = 88% and 93%, respectively). Our findings demonstrated that 14g and 14h are useful lead compounds and deserve further optimization and activity evaluation for the treatment of human cancers.

CBP/p300 Degrader: A Promising Therapeutic Strategy for Treatment of Prostate Cancer and Beyond.

Transcriptional coactivators CBP/p300 have emerged as potential targets for cancer therapeutics. This Viewpoint discusses recent results that demonstrate an exceptionally potent and orally efficacious CBP/p300 degrader for the treatment of prostate cancer. This degrader stands out as a promising new candidate for cancer therapy and deserves further research.

Ixekizumab for Active Radiographic Axial Spondyloarthritis in Chinese Patients: 16- and 52-Week Results from a Phase III, Randomized, Double-Blind, Placebo-Controlled Study.

INTRODUCTION: Ixekizumab, an interleukin-17A inhibitor, was efficacious and well tolerated for the treatment of active radiographic axial spondyloarthritis (r-axSpA) in international clinical studies. This phase III study aimed to determine the efficacy and safety of ixekizumab for treating Chinese patients with active r-axSpA. METHODS: Adults with active r-axSpA naïve to biologic disease-modifying antirheumatic drugs (bDMARDs), or with an inadequate response/intolerance to one tumor necrosis factor inhibitor, were randomized (1:1), double-blind, to receive ixekizumab 80 mg every 4 weeks (IXEQ4W; starting dose 160 mg), or placebo, for 16 weeks. Patients receiving placebo were then switched to IXEQ4W, and those receiving IXEQ4W continued, until week 52. The primary endpoint was the proportion of bDMARD-naïve patients achieving an Assessment of SpondyloArthritis International Society 40 (ASAS40) response at week 16. RESULTS: In total, 147 patients were randomized to receive placebo (n = 73) or IXEQ4W (n = 74). At week 16, more bDMARD-naive patients achieved ASAS40 in the IXEQ4W group (n = 66; 40.9%) than the placebo group (n = 64, 7.8%; p < 0.001). In the overall study population, ASAS40 was also achieved by more patients in the IXEQ4W group (37.8%) than the placebo group (8.2%; p < 0.001) at week 16, with a significant difference observed as early as week 1. There were significant improvements in all key secondary endpoints at week 16 with IXEQ4W versus placebo. Efficacy was sustained at week 52 in patients who continued IXEQ4W and there were also clinical improvements from weeks 16 to 52 in patients switched to IXEQ4W. The safety profile of ixekizumab was consistent with that described previously. Infections and injection-site reactions were the most frequently reported events of special interest. CONCLUSIONS: IXEQ4W was associated with rapid and significant improvements in the signs and symptoms of active r-axSpA in Chinese patients at week 16 that were sustained at week 52, with no new safety signals. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov identifier: NCT04285229.

Discovery of a potent and selective CBP bromodomain inhibitor (Y08262) for treating acute myeloid leukemia.

The bromodomain of CREB (cyclic-AMP response element binding protein) binding protein (CBP) is an epigenetic "reader" and plays a key role in transcriptional regulation. CBP bromodomain is considered to be a promising therapeutic target for acute myeloid leukemia (AML). Herein, we report the discovery of a series of 1-(indolizin-3-yl)ethan-1-one derivatives as potent, and selective CBP bromodomain inhibitors focused on improving cellular potency. One of the most promising compounds, 7e (Y08262), inhibits the CBP bromodomain at the nanomolar level (IC50 = 73.1 nM) with remarkable selectivity. In addition, the new inhibitor also displays potent inhibitory activities in AML cell lines. Collectively, this study provides a new lead compound for further validation of CBP bromodomain as a molecular target for AML drug development.

Efficacy and safety of tofacitinib in Chinese patients with active psoriatic arthritis: a phase 3, randomised, double-blind, placebo-controlled study.

OBJECTIVES: Efficacy and safety of tofacitinib, an oral Janus kinase inhibitor, were evaluated in a 6-month, double-blind, phase 3 study in Chinese patients with active (polyarthritic) psoriatic arthritis (PsA) and inadequate response to ≥1 conventional synthetic disease-modifying antirheumatic drug. METHODS: Patients were randomised (2:1) to tofacitinib 5 mg twice daily (N=136) or placebo (N=68); switched to tofacitinib 5 mg twice daily after month (M)3 (blinded). PRIMARY ENDPOINT: American College of Rheumatology (ACR50) response at M3. Secondary endpoints (through M6) included: ACR20/50/70 response; change from baseline in Health Assessment Questionnaire-Disability Index (HAQ-DI); ≥75% improvement in Psoriasis Area and Severity Index (PASI75) response, and enthesitis and dactylitis resolution. Safety was assessed throughout. RESULTS: The primary endpoint was met (tofacitinib 5 mg twice daily, 38.2%; placebo, 5.9%; p<0.0001). M3 ACR20/ACR70/PASI75 responses, and enthesitis and dactylitis resolution rates, were higher and HAQ-DI reduction was greater for tofacitinib 5 mg twice daily versus placebo. Incidence of adverse events (AEs)/serious AEs (M0-3): 68.4%/0%, tofacitinib 5 mg twice daily; 75.0%/4.4%, placebo. One death was reported with placebo→tofacitinib 5 mg twice daily (due to accident). One serious infection, non-serious herpes zoster, and lung cancer case each were reported with tofacitinib 5 mg twice daily; four serious infections and one non-serious herpes zoster case were reported with placebo→tofacitinib 5 mg twice daily (M0-6). No non-melanoma skin cancer, major adverse cardiovascular or thromboembolism events were reported. CONCLUSION: In Chinese patients with PsA, tofacitinib efficacy was greater than placebo (primary and secondary endpoints). Tofacitinib was well tolerated; safety outcomes were consistent with the established safety profile in PsA and other indications. TRIAL REGISTRATION NUMBER: NCT03486457.

Structural insights revealed by the cocrystal structure of CCS1477 in complex with CBP bromodomain.

Inhibition of the bromodomain of the CREB (cyclic-AMP response element-binding protein) binding protein (CBP) is a particularly promising new therapeutic approach for cancer. Benzimidazole derivatives CCS1477 and its analogues (8 and 9) are highly potent and selective CBP bromodomain inhibitors, with Kd values of 26.4, 37.0, and 34.3 nM in ITC assay, respectively. Among these compounds, CCS1477 is undergoing phase Ib/IIa clinical trials for the treatment of various cancers. Thus, we determined the co-crystal structures of CCS1477 and its analogues in complex with CBP bromodomain and revealed the detailed binding modes. Furthermore, overlapping with other reported co-crystal structures allowed us to identify that interaction with Arg1173, LPF shelf, and ZA channel was critical for keeping strong biological activity and selectivity. Collectively, this study provided a structural basis for CBP bromodomain inhibitors design.

Discovery, optimization and evaluation of 1-(indolin-1-yl)ethan-1-ones as novel selective TRIM24/BRPF1 bromodomain inhibitors.

TRIM24 (tripartite motif-containing protein 24) and BRPF1 (bromodomain and PHD finger containing protein 1) are epigenetics "readers" and potential therapeutic targets for cancer and other diseases. Here we describe the structure-guided design of 1-(indolin-1-yl)ethan-1-ones as novel TRIM24/BRPF1 bromodomain inhibitors. The representative compound 20l (Y08624) is a new TRIM24/BRPF1 dual inhibitor, with IC50 values of 0.98 and 1.16 µM, respectively. Cellular activity of 20l was validated by viability assay in prostate cancer (PC) cell lines. In PC xenograft models, 20l suppressed tumor growth (50 mg/kg/day, TGI = 53%) without exhibiting noticeable toxicity. Compound 20l represents a versatile starting point for the development of more potent TRIM24/BRPF1 inhibitors.

Design, Synthesis, and Biological Evaluation of 1-(Indolizin-3-yl)ethan-1-ones as CBP Bromodomain Inhibitors for the Treatment of Prostate Cancer.

CREB (cyclic-AMP responsive element binding protein) binding protein (CBP) is a potential target for prostate cancer treatment. Herein, we report the structural optimization of a series of 1-(indolizin-3-yl)ethan-1-one compounds as new selective CBP bromodomain inhibitors, aiming to improve cellular potency and metabolic stability. This process led to compound 9g (Y08284), which possesses good liver microsomal stability and pharmacokinetic properties (F = 25.9%). Furthermore, the compound is able to inhibit CBP bromodomain as well as the proliferation, colony formation, and migration of prostate cancer cells. Additionally, the new inhibitor shows promising antitumor efficacy in a 22Rv1 xenograft model (TGI = 88%). This study provides new lead compounds for further development of drugs for the treatment of prostate cancer.