Kwee Hyun Suh

Antitumor activity of HM781-36B, a highly effective pan-HER inhibitor in erlotinib-resistant NSCLC and other EGFR-dependent cancer models†

The epidermal growth factor receptor (EGFR) family of receptor tyrosine kinases has been implicated in a variety of cancers. In particular, activating mutations such as the L858R point mutation in exon 21 and the small in‐frame deletions in exon 19 of the EGFR tyrosine kinase domain are correlated with sensitivity to EGFR tyrosine kinase inhibitors in non‐small cell lung cancer (NSCLC) patients. Clinical treatment of patients is limited by the development of drug resistance resulting mainly from a gatekeeper mutation (T790M). In this study, we evaluated the therapeutic potential of a novel, irreversible pan‐HER inhibitor, HM781‐36B. The results from this study show that HM781‐36B is a potent inhibitor of EGFR in vitro, including the EGFR‐acquired resistance mutation (T790M), as well as HER‐2 and HER‐4, compared with other EGFR tyrosine kinases inhibitors (erlotinib, lapatinib and BIBW2992). HM781‐36B treatment of EGFR DelE746_A750‐harboring erlotinib‐sensitive HCC827 and EGFR L858R/T790M‐harboring erlotinib‐resistant NCI‐H1975 NSCLC cells results in the inhibition of EGFR phosphorylation and the subsequent deactivation of downstream signaling proteins. Additionally, HM781‐36B shows an excellent efficacy in a variety of EGFR‐ and HER‐2‐dependent tumor xenograft models, including erlotinib‐sensitive HCC827 NSCLC cells, erlotinib‐resistant NCI‐H1975 NSCLC cells, HER‐2 overexpressing Calu‐3 NSCLC cells, NCI‐N87 gastric cancer cells, SK‐Ov3 ovarian cancer cells and EGFR‐overexpressing A431 epidermoid carcinoma cancer cells. On the basis of these preclinical results, HM781‐36B is the most potent pan‐HER inhibitor, which will be advantageous for the treatment of patients with NSCLC including clinical limitation caused by acquired mutation (EGFR T790M), breast cancer and gastric cancer.

HM71224, a novel Bruton’s tyrosine kinase inhibitor, suppresses B cell and monocyte activation and ameliorates arthritis in a mouse model: a potential drug for rheumatoid arthritis

BackgroundBruton’s tyrosine kinase (Btk) is critical for activation of B cells and myeloid cells. This study aimed to characterize the effects of HM71224, a novel Btk inhibitor, both in vitro and in a mouse model of experimental arthritis.MethodsThe kinase inhibition profile of HM71224 was analyzed. The in vitro effects of HM71224 on B cells and monocytes were analyzed by examining phosphorylation of Btk and its downstream signaling molecules, along with cytokine production and osteoclast formation. The in vivo effects of HM71224 were investigated in a mouse model of collagen-induced arthritis (CIA).ResultsHM71224 irreversibly bound to and inhibited Btk (IC50 = 1.95 nM). The compound also inhibited the phosphorylation of Btk and its downstream molecules such as PLCγ2, in activated Ramos B lymphoma cells and primary human B cells in a dose-dependent manner. Furthermore, HM71224 effectively inhibited the production of tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1β by human monocytes, and osteoclast formation by human monocytes. Finally, HM71224 improved experimental arthritis and prevented joint destruction in a murine model of CIA.ConclusionsHM71224 inhibits Btk in B cells and monocytes and ameliorates experimental arthritis in a mouse model. Thus, HM71224 is a potential novel therapeutic agent for rheumatoid arthritis in humans.

Abstract LB-100: Discovery of HM61713 as an orally available and mutant EGFR selective inhibitor

Introduction: Activating mutations of EGFR are well known as oncogenic driver mutations in lung adenocarcinoma. Currently, EGFR TKIs including Gefitinib and Erlotinib are used as the first line therapy in NSCLC patients harboring EGFR activating mutations. However, drug resistance caused by T790M mutation limits the efficacy of these 1st generation EGFR TKIs. Currently, some of the next generation EGFR TKIs are under investigation for the treatment of lung cancer patients having T790M mutation. In our current presentation, to obtain HM61713, an EGFR mutant selective inhibitor, as a clinical candidate and the evaluation of HM61713 for mutant EGFR cancer model will be introduced. Method: Novel analogues were designed and synthesized to find active compounds for the T790M mutation as well as EGFR activating mutations with good selectivity over wild- type EGFR. Finally, HM61713 was selected as a clinical candidate through multi-optimization processes including both in vitro and in vivo pharmacologcal studies. Results: HM61713 was designed as an irreversible kinase inhibitor having a Michael acceptor, which covalently binds to a cysteine residue near the kinase domain of mutant the EGFR. In a cell wash out test, HM61713 inhibited phospho-EGFR for a long duration with a half-life of over 24 hours. From in vitro study, HM61713 showed potent activities for H1975 (L858-T790M) and HCC827 (exon 19 del.) with GI50 values of 9.2 nM and 10 nM, respectively. Instead, it showed low potency for H358 (wild type EGFR NSCLC) with GI50 of 2,225 nM. In xenograft studies using H1975 and HCC827, HM61713 resulted in good efficacy without showing any side effects. Conclusion: HM61713 showed excellent in vitro and in vivo activities for H1975 harboring L858R-T790M mutation as well as HCC827 having exon 19 deletion mutation with selectivity over wild-type EGFR. Currently, HM61713 is undergoing phase I study (NCT01588145) for NSCLC patients after the failure of 1st generation EGFR TKIs in Korea. Citation Format: Kwang-Ok Lee, Mi Young Cha, Mira Kim, Ji Yeon Song, Jae-Ho Lee, Young Hoon Kim, Young-Mi Lee, Kwee Hyun Suh, Jeewoong Son. Discovery of HM61713 as an orally available and mutant EGFR selective inhibitor. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr LB-100. doi:10.1158/1538-7445.AM2014-LB-100

Synthesis of proline analogues as potent and selective cathepsin S inhibitors

Cathepsin S is a potential target of autoimmune disease. A series of proline derived compounds were synthesized and evaluated as cathepsin S inhibitors. We discovered potent cathepsin S inhibitors through structure-activity relationship studies of proline analogues. In particular, compound 19-(S) showed promising in vitro/vivo pharmacological activities and properties as a selective cathepsin S inhibitor.

Discovery of novel pyrimidine and malonamide derivatives as TGR5 agonists.

Takeda G-protein-coupled receptor 5 (TGR5) is a promising molecular target for metabolic diseases. A series of 4-(2,5-dichlorophenoxy)pyrimidine and cyclopropylmalonamide derivatives were synthesized as potent agonists of TGR5 based on a bioisosteric replacement strategy. Several compounds exhibited improved potency, compared to a reference compound with a pyridine scaffold. The pharmacokinetic profile of the representative compound 18 was considered moderate.

Abstract LB-256: Optimal clinical dose-finding strategies: Translational preclinical pharmacokineitcs, pharmacodynamics, and efficacy analysis of HM61713, an orally selective EGFR mutant inhibitor

The first-generation of EGFR1 inhibitors (Gefitinib and Erlotinib) has significant clinical benefits in NSCLC caused by activating mutations, but the efficacy of these agents is often limited due to the emergence of drug resistance conferred by a gatekeeper residue, T790M. HM61713 is a third-generation EGFR tyrosine kinase inhibitor that has been evaluated as a novel therapeutic agent for the treatment of non-small cell lung cancer (NSCLC) with EGFR mutations. HM61713 is an orally active and a novel EGFR mutant selective inhibitor which is potent on resistance mutation (T790M) without affecting EGFR wild type at efficacious dose level. HM61713 showed an anti-cancer activity in several EGFR mutant lung cancer cell lines including T790M mutation harboring cell line. Integrated pharmacokinetic - pharmacodynamic - xenograft tumor model (PK-PD-XTG) was used to characterize the relationship between HM61713 plasma concentration and tumor growth inhibition (TGI) in H1975 (T790M mutation) xenograft model. Simple one-compartment model applied re-absorption compartment with first-order absorption/elimination was used to describe HM61713 plasma concentration-time profiles. Biophase distribution model with baseline inhibition E max equation was applied to characterize the PD marker (p-EGFR) and tumor volume shrinkage was explained by michaelis-menten kinetics of p-EGFR. Estimated in vivo IC 50 value of p-EGFR inhibition (%) based on plasma free concentration in xenograft mice was 1.14 ng/mL. The human PD marker response curve and the tumor growth inhibition plot were obtained by replacing the mice PK to human PK in our developed model based on the hypothesis thattranslation providesa good relationship of surrogate mice tumor PD to human tumor regression corresponding human PK. According to our simulated curves, we predicted appropriate human active dose from 300 to 800 mg/man and it would be an efficacious dose in patients with NSCLC harboring the EGFR activating and also with T790M resistant mutation. Currently, HM61713 is undergoing in clinical trial phase I/II in NSCLC (ClinicalTrials.gov, NCT01588145). Citation Format: Jooyun Byun, Taehun Song, Donghyun Kim, Junhyeng Son, Kwang-Ok Lee, Jaeho Lee, Yong Hoon Kim, Young-Mi Lee, Kwee Hyun Suh. Optimal clinical dose-finding strategies: Translational preclinical pharmacokineitcs, pharmacodynamics, and efficacy analysis of HM61713, an orally selective EGFR mutant inhibitor. [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 LB-256. doi:10.1158/1538-7445.AM2015-LB-256

ICP–MS in drug development: high-throughput analysis of strontium and calcium in bone, tissue and plasma

BACKGROUND The high-throughput analysis of strontium and calcium in plasma, tissue and bone (femur) using inductively coupled plasma-MS is described. Method validation, the results and experience obtained during sample analysis are highlighted. RESULTS The different matrices were destructed with concentrated nitric acid by heating at 60°C overnight. Using this approach it was possible to analyze large numbers of samples in parallel. CONCLUSION Inductively coupled plasma-MS proved to be a highly sensitive, robust and efficient technique for the analysis of several different biological samples. A total of 6767 samples were analyzed, and the performance of the method was illustrated by the fact that only 0.2% of the samples had to be reanalyzed due to anomalous results and ISR for all matrices fulfilled the acceptance criteria.

Abstract 2607: Antitumor activity of the selective RAF inhibitor HM95573 in solid tumors and hematologic malignancies

The mitogen-activated protein kinase (MAPK) pathway is particularly important for the survival and proliferation of tumor cells. Activation of the MAPK pathway due to mutations in BRAF, NRAS and KRAS is considered one of the causes of solid tumors (NSCLC, CRC,HCC, andthyroid cancers) and hematologic malignancies. HM95573 is a novel, highly potent RAF kinase inhibitor. Biochemically assayed for over 120 kinases, HM95573 showed the high selectivity toward BRAF mutant and CRAF kinases. The half maximal inhibition concentrations (IC50) of HM95573 against BRAFWT, BRAFV600E and CRAF kinases were 41nM, 7nM and 2nM, respectively. The strongly inhibited kinases subsequent to RAF kinases appeared to be CSF1R (44nM), DDR1 (77nM) and DDR2 (182 nM). HM95573 potently inhibited the growth of BRAFmutation CRC cell lines (e.g. IC50: 118nM for Colo-205) and thyroid cancer cell lines (43nM for B-CPAP); KRAS mutation NSCLC cell lines(297nM for Calu-6),CRC cell lines(65nM for HCT-116) and thyroid cancer cell lines(479nM for CAL-62); and NRAS mutation HCC cell lines(28nM for HepG2) andleukemia cell lines (39nM for HL-60). HM95573 effectively inhibited the phosphorylations of MEK and ERK, downstream kinases associated with cell proliferation in tumor cell lines mutated in BRAF, KRAS and NRAS. In addition, the phosphorylation of downstream kinases of RAF such as MEK and ERK was effectively inhibited with treatment of HM95573 in mutant KRAS NSCLC and CRC cells. HM95573 showed the excellent antitumor activity in mouse models xenografted with BRAF mutation cell line (Colo-205), KRAS mutation cell lines (Calu-6 and HCT-116)and NRAS mutation cell line (HepG2)two RAF inhibitors approved in melanoma which were effective to only BRAF mutation cell lines under conditions tested. The in vivo antitumor activity of HM95573 was potentiated with MEK inhibitors. Now, HM95573 is currently in phase I development in patients with advanced solid tumors including KRAS mutation NSCLC in Korea. Citation Format: Young-Mi Lee, InHwan Bae, Namgoong Gwang Mo, Jae Ho Lee, Suhyeon Kim, Ji Yeon Song, Kyu Hang Lee, Tae Hun Song, Young Gil Ahn, Young Hoon Kim, Kwee Hyun Suh. Antitumor activity of the selective RAF inhibitor HM95573 in solid tumors and hematologic malignancies. [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 2607. doi:10.1158/1538-7445.AM2015-2607

Abstract LB-389: Antitumor activity of HM781–36B, a highly effective pan-HER inhibitor in erlotinib-resistant NSCLC and other EGFR-dependent cancer models

The epidermal growth factor receptor (EGFR) family of receptor tyrosine kinases has been implicated in a variety of cancers. In particular, activating mutations such as the L858R point mutation in exon 21 and the small in-frame deletions in exon 19 of the EGFR tyrosine kinase domain are correlated with sensitivity to EGFR tyrosine kinase inhibitors in non-small cell lung cancer (NSCLC) patients. But clinical treatment is limited by the development of drug resistance resulting mainly from an acquired mutation (T790M). In this study, we evaluated the therapeutic potential of a novel, irreversible pan-HER inhibitor, HM781–36B. We demonstrated that HM781–36B is a potent EGFR inhibitor including the EGFR -acquired resistance mutation (IC 50 4.2 nM in EGFR T790M and IC 50 2.2 nM in EGFR L858R/T790M ), as well as EGFR, HER-2 and HER-4 (IC 50 3.2 nM, 5.3 nM and 23.5 nM, respectively), compared to other EGFR tyrosine kinases inhibitors (erlotinib, lapatinib and BIBW-2992), with kinase selectivity confirmed by 77 kinases panel assay except for Blk, Bmx and Btk. Strong growth inhibitory activity by the treatment of HM781–36B was confirmed with the range of IC 50 0.6–6nM in NSCLC (HCC827, H358, H1975, Calu-3, and H1781), breast cancer (SK-Br3, BT474, MDA-175, and MDA-453), and gastric cancer (N87 and SNU-216) cell lines. HM781–36B showed 400–4,000 fold low growth inhibitory effect against normal cell lines (Hs-27 and Balb/c 3T3) relative to cancer cell lines. HM781–36B treatment results in the inhibition of EGFR phosphorylation and the subsequent deactivation of downstream signaling proteins in EGFR DelE746_A750-harboring erlotinib-sensitive HCC827 and EGFR L858R/T790M-harboring erlotinib-resistant NCI-H1975 NSCLC cells. HM781–36B interacts directly with its target enzyme ( EGFR WT , EGFR T790M , HER-2), which was confirmed through prolongation study of phosphorylation inhibitory effect in A431 and SK-Br3 cells and direct fluorescence-based SDS-PAGE analysis by the incubation of Cy3-labeled HM781–36B probe. This irreversible occupation at the kinase domain leads to excellent in vivo efficacy of HM781–36B (1mg/kg – 5mg/kg) toward various xenograft models with EGFR-dependent cancers cells, including erlotinib-sensitive HCC827 NSCLC cells, erlotinib-resistant H1975 NSCLC cells, HER-2 overexpressing Calu-3 NSCLC cells, N87 gastric cancer cells, and SK-Ov3 ovarian cancer cells, and EGFR-overexpressing A431 epidermoid carcinoma cancer cells. On the basis of these preclinical results, HM781–36B was selected as a candidate for clinical development and a phase I study of HM781–36B is currently undergoing in South Korea. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-389. doi:10.1158/1538-7445.AM2011-LB-389