Lianshan Zhang

Metabolic characterization of pyrotinib in humans by ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry.

Pyrotinib is a novel irreversible tyrosine kinase inhibitor developed for the treatment of human epidermal growth factor receptor 2 (HER2)-positive breast cancer. The results of phase I clinical trial demonstrated that pyrotinib was well tolerated and exhibited potent antitumor activity. As a promising therapeutic agent for HER2-positive breast cancer, it is of great importance to investigate the biotransformation of pyrotinib in humans and identify the major enzymes involved in its metabolism during its early stage of development for safety consideration. For this purpose, a robust analytical method based on ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF MS) was established to characterize the metabolites of pyrotinib in human plasma, feces, and urine, and identify the primary enzymes responsible for its metabolism. As a result, a total of 24 metabolites were identified, including 16 phase I metabolites resulting from dealkylation, oxidation, dehydrogenation, and carbonylation, and 8 phase II metabolites originating from cysteine and N-acetylcysteine conjugation. Pyrotinib was absorbed into blood by 1h, reached its peak level at 4h, and afterwards underwent slow elimination. The principal metabolites detected in humans (M1, M2, and M5) were products resulting from O-depicoline and pyrrolidine lactam formation, whose structures have been confirmed by the synthetic references. In addition, fecal clearance was the major route of excretion for pyrotinib. Further phenotyping experiment proved that CYP3A4 was the most active enzyme responsible for the biotransformation of pyrotinib, implying the vital necessity of the assessment of the potential CYP3A-mediated drug-drug interactions in humans. Taken together, this study provided valuable metabolic data to explicate the dynamic process of pyrotinib in humans, and important reference basis for its safety evaluation and rational clinical application. The results will also benefit the assessment of the contributions to the overall activity or toxicity from the key metabolites.

Discovery of EBI-907: A highly potent and orally active B-Raf(V600E) inhibitor for the treatment of melanoma and associated cancers.

A novel series of pyrazolo[3,4-c]isoquinoline derivatives was discovered as B-Raf(V600E) inhibitors through scaffold hopping based on a literature lead PLX4720. Further SAR exploration and optimization led to the discovery of potent B-Raf(V600E) inhibitors with good oral bioavailability in rats and dogs. One of the compounds EBI-907 (13g) demonstrated excellent in vivo efficacy in B-Raf(V600E) dependent Colo-205 tumor xenograft models in mouse and is under preclinical studies for the treatment of melanoma and B-Raf(V600E) associated cancers.

Discovery and development of pyrotinib: A novel irreversible EGFR/HER2 dual tyrosine kinase inhibitor with favorable safety profiles for the treatment of breast cancer

Abstract The discovery and development of a novel irreversible EGFR/HER2 dual tyrosine kinase inhibitor SHR1258 (pyrotinib) for the treatment of HER2‐postive breast cancer is presented. The structure‐activity relationship of lead series and their pharmacokinetic properties were evaluated to identify the potential candidates for further in vivo efficacy studies and preclinical safety assessments. Metabolic pathway and drug‐drug interaction were also investigated in preclinical settings. In particular, major metabolites in human and animal species were assessed with regard to potential toxicity or off‐target side effects. Overall, the potent and selective EGFR/HER2 dual inhibitor, pyrotinib, displayed robust anti‐tumor effects on HER2‐overexpressing xenograft models and sufficiently safety windows in animals as well as favorable pharmacokinetic properties in human, which substantially ensures current clinical development. Finally, recent advances of pyrotinib in clinical studies are highlighted with very encouraging outcomes in patients with HER2‐postive advanced breast cancer. Graphical abstract Figure. No Caption available.

Discovery of EBI-2511: A Highly Potent and Orally Active EZH2 Inhibitor for the Treatment of Non-Hodgkin’s Lymphoma

A novel series of benzofuran derived EZH2 inhibitors were discovered through a scaffold hopping approach based on the clinical compound of EPZ-6438. Further rational structure-activity relationship exploration and optimization led to the discovery of more potent EZH2 inhibitors with oral bioavailability in mice and rats. A lead compound EBI-2511 (compound 34) demonstrated excellent in vivo efficacy in Pfeiffer tumor Xenograft models in mouse and is under preclinical development for the treatment of cancers associated with EZH2 mutations.

Discovery of EBI-1051: A novel and orally efficacious MEK inhibitor with benzofuran scaffold

A novel series of benzodihydrofuran derivatives was developed as potent MEK inhibitors through scaffold hopping based on known clinical compounds. Further SAR exploration and optimization led to another benzofuran series with good oral bioavailability in rats. One of the compounds EBI-1051 (28d) demonstrated excellent in vivo efficacy in colo-205 tumor xenograft models in mouse and is suitable for pre-clinical development studies for the treatment of melanoma and MEK associated cancers. Compared to AZD6244, EBI-1051 showed superior potency in some cancer cell lines such as colon-205, A549 and MDA-MB-231.

Abstract 2599: Discovery and pharmacological characterization of the second generation of Btk inhibitors with improved target selectivity and enhanced in vivo efficacy

Bruton9s tyrosine kinase (Btk) is an essential component of the B-cell receptor (BCR) signaling pathways regulating survival, activation, proliferation, and differentiation of B lymphocytes. The first Btk inhibitor, Ibrutinib, has demonstrated a significant clinical efficacy in a variety of B-cell malignancies. Through structure-guided approach, we have discovered two series of novel and potent Btk inhibitors, represented by EBI-1266 and EBI-1367, respectively. Both of these compounds showed high potency in inhibiting Btk kinase activity and growth of a number of aggressive lymphoma cell lines driven by aberrant BCR signaling, with IC50 value within low nanomolar range. Mechanistic studies examining BCR signaling pathway in related B cell lymphoma cell lines revealed that both EBI-1266 and EBI-1367 potently inhibited Btk phosphorylation and downstream Erk phosphorylation, similar to Ibrutinib. Furthermore, each compound showed unique and significant superiority over Ibrutinib: EBI-1266 had a cleaner selectivity profile against a panel of kinases with a cysteine residue in the conserved catalytic domain, and EBI-1367 exhibited >10-fold higher in vivo exposure in multiple preclinical species. In a tumor xenograft mouse model where tumor growth is dependent on Btk activity, both EBI-1266 and EBI-1367 showed significant oral anti-tumor activities, with EBI-1367 being more efficacious than Ibrutinib, consistent with a higher exposure of EBI-1367 in both blood and tumor tissues. No evidence of overt toxicities was observed in rodents with prolonged oral administration for two weeks with doses at least 3-fold above a highly efficacious dose. In summary, the pharmacological profiles of EBI-1266 and EBI-1367 indicate that these compounds have a great potential to become the next generation of Btk inhibitors, offering advantages in pharmaceutical development, enhanced in vivo efficacy and reduced toxicities. We are currently performing IND-enabling studies aiming to initiate phase I clinical trials for these Btk inhibitors. Citation Format: Jiayin Zhang, Dong Liu, Ru Shen, Yinfa Yan, Liuqing Yang, Minsheng Zhang, Jun Feng, Beibei Fu, Jerry Hu, Biao Lu, Hong Wan, Lei Zhang, Weikang Tao, Lianshan Zhang, Jingsong Cao. Discovery and pharmacological characterization of the second generation of Btk inhibitors with improved target selectivity and enhanced in vivo efficacy. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2599. doi:10.1158/1538-7445.AM2015-2599

WITHDRAWN: Discovery of SHR1977: A highly potent and selective ROMK inhibitor.

This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.

Abstract C254: Discovery of a novel and potent BRAF (V600E) inhibitor with a unique kinase targeting profile, EBI-907: Pharmacological characterization and potential to overcome drug resistance and paradoxical activation.

The RAS/RAF/MEK/ERK pathway plays a central role in regulating cell proliferation, differentiation, and growth. The oncogenic mutation of BRAF (V600E) has been found in 8% of all human cancers, including more than 60% of melanoma, 45% of papillary thyroid cancer, 10% of colorectal cancers, and a small subset of ovarian, breast, lung cancers, and leukemia. Although BRAF-specific inhibitors such as Vemurafenib (PLX-4032) and Dabrafenib (GSK2118436) have been approved by FDA and several other BRAF inhibitors are at different stages of clinical development, they carry some liabilities and drug resistance rapidly developed. We have sought to identify and develop more potent BRAF (V600E) inhibitors with favorable pharmacological and safety profiles. Our chemistry effort has led to the discovery of EBI-907 as a novel BRAF (V600E) inhibitor with potent anti-tumor activity in vitro and in vivo. In a LanthaScreen BRAF (V600E) kinase assay, EBI-907 is a highly potent inhibitor displaying a low single-digit nanomolar activity (IC50 = 4.9 nM), which is >10-fold more potent than Vemurafenib (IC50 = 59 nM). EBI-907 also exhibits high potency in selectively inhibiting the proliferation of BRAF (V600E)-dependent cell lines (A375 and Colo205) and cellular Erk phosporylation, with superior activity to Vemurafenib. In multiple preclinical species (mice, rats, and dogs), EBI-907 exhibited an excellent oral bioavailability. In a BRAF (V600E)-dependent human Colo-205 tumor xenograft mouse model, EBI-907 caused a partial or complete tumor regression in a dose-dependent manner, with superior efficacy than Vemurafenib. In addition, we have also observed a broader kinase selectivity profile for EBI-907, displaying potent activity against a number of important oncogenic kinases including BRK, FGFR1, c-Kit, and PDGFRb. Preliminary toxicity studies in rodent models showed that EBI-907 was well tolerated and has a high safety margin. More importantly, EBI-907 showed a favorable pattern of drug-induced paradoxical activation of MAPK pathway, pointing to a possibility to “break” the inhibitor paradox. Finally, our results showed that combined use of EBI-907 and a MEK inhibitor completely abolished the paradoxical activation and overcame the drug resistance induced by BRAF inhibitor alone. Our findings not only present EBI-907 as a potent and promising BRAF inhibitor, but also point out a possibility to develop next generation targeted therapies to treat BRAF mutated cancers. Citation Information: Mol Cancer Ther 2013;12(11 Suppl):C254. Citation Format: Jiayin Zhang, Dong Liu, Ru Shen, Yinfa Yan, Liuqing Yang, Minsheng Zhang, Guoqing Cao, Hu Cao, Beibei Fu, Aishen Gong, Biao Lu, Qiming Sun, Hong Wan, Pangke Yan, Lei Zhang, Lianshan Zhang, Jingsong Cao. Discovery of a novel and potent BRAF (V600E) inhibitor with a unique kinase targeting profile, EBI-907: Pharmacological characterization and potential to overcome drug resistance and paradoxical activation. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr C254.