Allosteric SHP2 Inhibitor Research Articles

Previously Published Phosphatase Probes Have Limited Utility Due To Their Unspecific Reactivity.

This study explores using activity-based protein profiling to target protein tyrosine phosphatases. With the discovery of allosteric SHP2 inhibitors, this enzyme family has resurfaced as interesting drug targets. Therefore, we envisioned that previously described direct electrophiles and quinone methide-based traps targeting phosphatases could be applied in competitive activity-based protein profiling assays. This study evaluates three direct electrophiles, specifically, a vinyl sulfonate, a vinyl sulfone, and an α-bromobenzylphosphonate as well as three quinone methide-based traps as activity-based probes. For all these moieties it was previously shown that they could selectively engage with phosphatases in assays with purified enzymes or overexpressed phosphatases in bacterial lysates. However, this study demonstrates that probes based on these moieties all suffer from unspecific labelling. Direct electrophiles were either unspecific or not activity-based, while quinone methide-based traps showed dependence on phosphatase activity but also resulted in unspecific labelling due to diffusion after activation. This phenomenon, termed 'bystander' labelling, occurred even with catalytically inactive SHP2 mutants. We concluded that alternative strategies or chemistries are needed to apply activity-based protein profiling in phosphatase research. Moreover, this study shows that quinone methide-based designs have limited potential in probe and inhibitor development strategies due to their intrinsic reactivity.

Design, Synthesis and Antitumor Activity of a Novel Class of SHP2 Allosteric Inhibitors with a Furanyl Amide-Based Scaffold.

SHP2 plays a critical role in modulating tumor growth and PD-1-related signaling pathway, thereby serving as an attractive antitumor target. To date, no antitumor drugs targeting SHP2 have been approved, and hence, the search of SHP2 inhibitors with new chemical scaffolds is urgently needed. Herein, we developed a novel SHP2 allosteric inhibitor SDUY038 with a furanyl amide scaffold, demonstrating potent binding affinity (KD = 0.29 μM), enzymatic activity (IC50 = 1.2 μM) and similar binding interactions to SHP099. At the cellular level, SDUY038 exhibited pan-antitumor activity (IC50 = 7-24 μM) by suppressing pERK expression. Furthermore, SDUY038 significantly inhibited tumor growth in both xenograft and organoid models. Additionally, SDUY038 displayed acceptable bioavailability (F = 14%) and half-life time (t1/2 = 3.95 h). Conclusively, this study introduces the furanyl amide scaffold as a novel class of SHP2 allosteric inhibitors, offering promising lead compounds for further development of new antitumor therapies targeting SHP2.

Off-target autophagy inhibition by SHP2 allosteric inhibitors contributes to their antitumor activity in RAS-driven cancers.

Aberrant activation of RAS/MAPK signaling is common in cancer, and efforts to inhibit pathway components have yielded drugs with promising clinical activities. Unfortunately, treatment-provoked adaptive resistance mechanisms inevitably develop, limiting their therapeutic potential. As a central node essential for receptor tyrosine kinase-mediated RAS activation, SHP2 has emerged as an attractive cancer target. Consequently, many SHP2 allosteric inhibitors are now in clinical testing. Here we discovered a previously unrecognized off-target effect associated with SHP2 allosteric inhibitors. We found that these inhibitors accumulate in the lysosome and block autophagic flux in an SHP2-independent manner. We showed that off-target autophagy inhibition by SHP2 allosteric inhibitors contributes to their antitumor activity. We also demonstrated that SHP2 allosteric inhibitors harboring this off-target activity not only suppress oncogenic RAS signaling but also overcome drug resistance such as MAPK rebound and protective autophagy in response to RAS/MAPK pathway blockage. Finally, we exemplified a therapeutic framework that harnesses both the on- and off-target activities of SHP2 allosteric inhibitors for improved treatment of mutant RAS-driven and drug-resistant malignancies such as pancreatic and colorectal cancers.

Tyrosine phosphatase SHP2 aggravates tumor progression and glycolysis by dephosphorylating PKM2 in gastric cancer.

Gastric cancer (GC) is among the most lethal human malignancies, yet it remains hampered by challenges in fronter of molecular-guided targeted therapy to direct clinical treatment strategies. The protein tyrosine phosphatase Src homology 2 domain-containing phosphatase 2 (SHP2) is involved in the malignant progression of GC. However, the detailed mechanisms of the posttranslational modifications of SHP2 remain poorly understood. Herein, we demonstrated that an allosteric SHP2 inhibitor, SHP099, was able to block tumor proliferation and migration of GC by dephosphorylating the pyruvate kinase M2 type (PKM2) protein. Mechanistically, we found that PKM2 is a bona fide target of SHP2. The dephosphorylation and activation of PKM2 by SHP2 are necessary to exacerbate tumor progression and GC glycolysis. Moreover, we demonstrated a strong correlation between the phosphorylation level of PKM2 and adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) in GC cells. Notably, the low phosphorylation expression of AMPK was negatively correlated with activated SHP2. Besides, we proved that cisplatin could activate SHP2 and SHP099 increased sensitivity to cisplatin in GC. Taken together, our results provide evidence that the SHP2/PKM2/AMPK axis exerts a key role in GC progression and glycolysis and could be a viable therapeutic approach for the therapy of GC.

Discovery of TK-642 as a highly potent, selective, orally bioavailable pyrazolopyrazine-based allosteric SHP2 inhibitor

Src homology-2-containing protein tyrosine phosphatase 2 (SHP2) is a promising therapeutic target for cancer therapy. In this work, we presented the structure-guided design of 5,6-fused bicyclic allosteric SHP2 inhibitors, leading to the identification of pyrazolopyrazine-based TK-642 as a highly potent, selective, orally bioavailable allosteric SHP2 inhibitor (SHP2WT IC50 = 2.7 nmol/L) with favorable pharmacokinetic profiles (F = 42.5%; t1/2 = 2.47 h). Both dual inhibition biochemical assay and docking analysis indicated that TK-642 likely bound to the “tunnel” allosteric site of SHP2. TK-642 could effectively suppress cell proliferation (KYSE-520 cells IC50 = 5.73 μmol/L) and induce apoptosis in esophageal cancer cells by targeting the SHP2-mediated AKT and ERK signaling pathways. Additionally, oral administration of TK-642 also demonstrated effective anti-tumor effects in the KYSE-520 xenograft mouse model, with a T/C value of 83.69%. Collectively, TK-642 may warrant further investigation as a promising lead compound for the treatment of esophageal cancer.

Abstract 1969: Off-target autophagy inhibition by SHP2 allosteric inhibitors and therapeutic implications for aberrant RAS-driven cancers

Abstract Aberrant activation of RAS-MAPK signaling is common in cancer, and efforts to inhibit pathway components have yielded drugs with promising clinical activities. Unfortunately, treatment-provoked adaptive resistance mechanisms inevitably develop, limiting their therapeutic potential. As a central node essential for receptor tyrosine kinase mediated RAS activation, SHP2 has emerged as an attractive cancer target. Consequently, many SHP2 allosteric inhibitors are now in clinical testing. Here we discovered a previously unrecognized off-target effect associated with SHP2 allosteric inhibitors. We found that these inhibitors accumulate in the lysosome and block autophagic flux in a SHP2-independent manner. We showed that off-target autophagy inhibition by SHP2 allosteric inhibitors contributes to their anti-tumor activity. We also demonstrated that SHP2 allosteric inhibitors harboring this off-target activity not only suppress oncogenic RAS signaling but also overcome drug resistance such as MAPK rebound and protective autophagy in response to RAS-MAPK pathway blockage. Finally, we exemplified a new therapeutic framework that harnesses both the on- and off-target activities of SHP2 allosteric inhibitors for improved treatment of mutant RAS driven and drug resistant malignancies such as pancreatic and colorectal cancers. Citation Format: Yiming Miao, Yunpeng Bai, Jinmin Miao, Allison A. Murray, Jianping Lin, Jiajun Dong, Zihan Qu, Ruo-Yu Zhang, Quyen Nguyen, Shaomeng Wang, Zhong-Yin Zhang. Off-target autophagy inhibition by SHP2 allosteric inhibitors and therapeutic implications for aberrant RAS-driven cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1969.

Abstract 6060: Discovery of potent SHP2 protein degraders with strong anti-tumor activities in KRAS mutant cancers

Abstract Background: SHP2 plays a pivotal role in modulating the RTK/RAS/MAPK signaling pathway, which is frequently dysregulated in various cancers. Multiple allosteric SHP2 inhibitors have been under active development for the treatment of RTK/RAS/MAPK-dependent cancers, while certain limitations have come to light, such as their inability to target the active form of SHP2 and narrow therapeutic index necessitating intermittent dosing to mitigate toxicity. To overcome these challenges, we have discovered SHP2 protein degraders as next generation SHP2 targeting agents. Here, we present compelling profiles of our SHP2 degraders. Methods: We employed a variety of cancer cell lines harboring mutations in RTK, KRAS, or SHP2 for assessing in vitro activity of SHP2 degraders. For in vivo assessment of pharmacological profile, we utilized an NCI-H358 KRAS G12C mutant NSCLC xenograft. SHP2 protein levels in cell lysates and tumors were analyzed to assess SHP2 degradation efficiency. Simultaneously, ERK phosphorylation and DUSP6 mRNA levels were analyzed to evaluate downstream effects. Immunoprecipitation assays were used to assess the impact on SHP2's scaffolding roles. Results: A series of SHP2 degraders have been identified, demonstrating highly efficient SHP2 degradation activity with DC50 values in subnanomolar ranges. Robust inhibition of ERK phosphorylation, followed by remarkable anti-cancer effects in multiple KRAS mutant cancer cell lines were observed. Interestingly, in vitro cell growth inhibition by SHP2 degraders are 10 times more potent than SHP2 inhibitors currently under clinical development. Further characterization reveals several advantages of SHP2 degraders compared to SHP2 inhibitors. First, we observed a more efficient disruption of SHP2 scaffolding function, such as the formation of the SHP2-GRB2-GAB1 complex. Second, we detected effective degradation of activating mutants of SHP2, such as E76K and T507K, which are typically not targeted by SHP2 inhibitors. Experiments using a KRAS mutant CDX model demonstrate compelling in vivo profiles. A single administration of lead compounds resulted in Dmax values exceeding 95% in tumors, accompanied by the significant reduction of downstream signaling markers, such as p-ERK and DUSP6 mRNA. Notably, the reduced levels of SHP2 and downstream markers persist for several days. This suggests that utilizing intermittent dosing could be a viable approach with SHP2 degraders. Once-weekly intravenous administration achieved strong tumor growth inhibition without causing significant body weight loss. Conclusion: We have successfully discovered novel SHP2 degraders exhibiting remarkable activities. We demonstrate that SHP2 degraders have potential to overcome the limitations associated with allosteric SHP2 inhibitors and provide a promising therapeutic option for RTK/RAS/MAPK-dependent cancer patients. Citation Format: So Hyun Kim, Jihye Lee, Jiyoung Song, Geon-Tae Park, Jieun Jung, Jungtae Na, Dong Ho Lee, Soohyun Lee, Ji Youn Park, Jiyoung Kim, Onnuri Bae, Jeonghwa Han, Ju Young Kang, Mijin Moon, Yongje Shin, Je Ho Ryu, Song Hee Lee, Sook-Kyung Park. Discovery of potent SHP2 protein degraders with strong anti-tumor activities in KRAS mutant cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6060.

Tyrosine phosphatase PTPN11/SHP2 in solid tumors - bull's eye for targeted therapy?

Encoded by PTPN11, the Src-homology 2 domain-containing phosphatase 2 (SHP2) integrates signals from various membrane-bound receptors such as receptor tyrosine kinases (RTKs), cytokine and integrin receptors and thereby promotes cell survival and proliferation. Activating mutations in the PTPN11 gene may trigger signaling pathways leading to the development of hematological malignancies, but are rarely found in solid tumors. Yet, aberrant SHP2 expression or activation has implications in the development, progression and metastasis of many solid tumor entities. SHP2 is involved in multiple signaling cascades, including the RAS-RAF-MEK-ERK-, PI3K-AKT-, JAK-STAT- and PD-L1/PD-1- pathways. Although not mutated, activation or functional requirement of SHP2 appears to play a relevant and context-dependent dichotomous role. This mostly tumor-promoting and infrequently tumor-suppressive role exists in many cancers such as gastrointestinal tumors, pancreatic, liver and lung cancer, gynecological entities, head and neck cancers, prostate cancer, glioblastoma and melanoma. Recent studies have identified SHP2 as a potential biomarker for the prognosis of some solid tumors. Based on promising preclinical work and the advent of orally available allosteric SHP2-inhibitors early clinical trials are currently investigating SHP2-directed approaches in various solid tumors, either as a single agent or in combination regimes. We here provide a brief overview of the molecular functions of SHP2 and collate current knowledge with regard to the significance of SHP2 expression and function in different solid tumor entities, including cells in their microenvironment, immune escape and therapy resistance. In the context of the present landscape of clinical trials with allosteric SHP2-inhibitors we discuss the multitude of opportunities but also limitations of a strategy targeting this non-receptor protein tyrosine phosphatase for treatment of solid tumors.

Allosteric inhibitor of SHP2 enhances macrophage endocytosis and bacteria elimination by increasing caveolae activation and protects against bacterial sepsis

The uncontrolled bacterial infection-induced cytokine storm and sequential immunosuppression are commonly observed in septic patients, which indicates that the activation of phagocytic cells and the efficient and timely elimination of bacteria are crucial for combating bacterial infections. However, the role of dysregulated immune cells and their disrupted function in sepsis remains unclear. Here, we found that macrophages exhibited the impaired endocytosis capabilities in sepsis by Single-cell RNA sequencing and bulk RNA sequencing. Caveolae protein Caveolin-1 (Cav-1) of macrophages was inactivated by SHP2 rapidly during Escherichia coli (E.coli) infection. Allosteric inhibitor of SHP2 effectively maintains Cav-1 phosphorylation to enhance macrophage to endocytose and eliminate bacteria. Additionally, TLR4 endocytosis of macrophage was also enhanced upon E.coli infection by SHP099, inducing an increased and rapidly resolved inflammatory response. In vivo, pretreatment or posttreatment with inhibitor of SHP2 significantly reduced the bacterial burden in organs and mortality of mice subjected E.coli infection or CLP-induced sepsis. The cotreatment of inhibitor of SHP2 with an antibiotic conferred complete protection against mortality in mice. Our findings suggest that Cav-1-mediated endocytosis and bacterial elimination may play a critical role in the pathogenesis of sepsis, highlighting inhibitor of SHP2 as a potential therapeutic agent for sepsis.

Direct-to-biology platform: From synthesis to biological evaluation of SHP2 allosteric inhibitors

Tyrosine phosphatase SHP2 is a proto-oncogenic protein involved in cell growth and differentiation via diverse intracellular signaling pathways. With the scope of identifying new SHP2 allosteric inhibitors, we report here the development and optimization of a high-throughput “Direct-to-Biology” (D2B) workflow including the synthesis and the biological evaluation of the reaction crude, thus eliminating the need for purification. During this labor-saving procedure, the structural diversity was introduced through a SNAr reaction. A wide array of analogues with good chemical purity was generated, allowing the obtention of reliable biological data which validated this efficient technique. This approach enabled the fast evaluation of a variety of structurally diverse fragments leading to nanomolar SHP2 allosteric inhibitors and a new series bearing a novel bicyclo[3.1.0]hexane moiety.

Discovery of 1H-pyrazolo[3,4-b]pyrazine derivatives as selective allosteric inhibitor of protein tyrosine phosphatase SHP2 for the treatment of KRASG12C-mutant non-small cell lung cancer

The high expression or mutation of SHP2 can induce cancer, so targeting SHP2 has become a new strategy for cancer treatment. In this study, we used the previously reported SHP2 allosteric inhibitor IACS-13909 as a lead drug for structural derivation and modification, and synthesized three SHP2 inhibitors. Among them, 1H-pyrazolo[3,4-b]pyrazine derivative 4b was a highly selective SHP2 allosteric inhibitor, with an IC50 value of 3.2 nM, and its inhibitory activity was 17.75 times than that of the positive control IACS-13909. The cell proliferation experiment detected that compound 4b would markedly inhibit the proliferation of various cancer cells. Interestingly, compound 4b was highly sensitive to KRASG12C-mutant non-small cell lung cancer NCI-H358 cells, with an IC50 value of 0.58 μM and its antiproliferative activity was 4.79 times than that of IACS-13909. Furthermore, the combination therapy of compound 4b and KRASG12C inhibitor sotorasib would play a strong synergistic effect against NCI-H358 cells. The western blot experiment detected that compound 4b markedly downregulated the phosphorylation levels of ERK and AKT in NCI-H358 cells. Molecular docking study predicted that compound 4b bound to the allosteric site of SHP2 and formed H-bond interactions with key residues Thr108, Glu110, Arg111, and Phe113. In summary, this study aims to provide new ideas for the development of SHP2 allosteric inhibitors for the treatment of KRASG12C mutant non-small cell lung cancer. Communicated by Ramaswamy H. Sarma

Binding Free Energy Calculation Based on the Fragment Molecular Orbital Method and Its Application in Designing Novel SHP-2 Allosteric Inhibitors.

The accurate prediction of binding free energy is a major challenge in structure-based drug design. Quantum mechanics (QM)-based approaches show promising potential in predicting ligand-protein binding affinity by accurately describing the behavior and structure of electrons. However, traditional QM calculations face computational limitations, hindering their practical application in drug design. Nevertheless, the fragment molecular orbital (FMO) method has gained widespread application in drug design due to its ability to reduce computational costs and achieve efficient ab initio QM calculations. Although the FMO method has demonstrated its reliability in calculating the gas phase potential energy, the binding of proteins and ligands also involves other contributing energy terms, such as solvent effects, the 'deformation energy' of a ligand's bioactive conformations, and entropy. Particularly in cases involving ionized fragments, the calculation of solvation free energy becomes particularly crucial. We conducted an evaluation of some previously reported implicit solvent methods on the same data set to assess their potential for improving the performance of the FMO method. Herein, we develop a new QM-based binding free energy calculation method called FMOScore, which enhances the performance of the FMO method. The FMOScore method incorporates linear fitting of various terms, including gas-phase potential energy, deformation energy, and solvation free energy. Compared to other widely used traditional prediction methods such as FEP+, MM/PBSA, MM/GBSA, and Autodock vina, FMOScore showed good performance in prediction accuracies. By constructing a retrospective case study, it was observed that incorporating calculations for solvation free energy and deformation energy can further enhance the precision of FMO predictions for binding affinity. Furthermore, using FMOScore-guided lead optimization against Src homology-2-containing protein tyrosine phosphatase 2 (SHP-2), we discovered a novel and potent allosteric SHP-2 inhibitor (compound 8).

Complex Roles of PTPN11/SHP2 in Carcinogenesis and Prospect of Targeting SHP2 in Cancer Therapy

The nonreceptor tyrosine phosphatase SHP2 has been at the center of cell signaling research for three decades. SHP2 is required to fully activate the RTK/RAS/ERK signaling cascade, although the underlying mechanisms are not completely understood. PTPN11, which encodes SHP2, is the first identified proto-oncogene that encodes a tyrosine phosphatase, with dominantly activating mutations detected in leukemias and solid tumors. However, SHP2 has pro- and antioncogenic effects, and the most recent data reveal opposite activities of SHP2 in tumor cells and microenvironment cells. Allosteric SHP2 inhibitors show promising antitumor effects and overcome resistance to inhibitors of RAS/ERK signaling in animal models. Many clinical trials with orally bioactive SHP2 inhibitors, alone or combined with other regimens, are ongoing for a variety of cancers worldwide, with therapeutic outcomes yet unknown. This review discusses the multifaceted functions of SHP2 in oncogenesis, preclinical studies, and clinical trials with SHP2 inhibitors in oncological treatment.

Discovery of 5-Azaquinoxaline Derivatives as Potent and Orally Bioavailable Allosteric SHP2 Inhibitors.

SHP2 has emerged as an important target for oncology small-molecule drug discovery. As a nonreceptor tyrosine phosphatase within the MAPK pathway, it has been shown to control cell growth, differentiation, and oncogenic transformation. We used structure-based design to find a novel class of potent and orally bioavailable SHP2 inhibitors. Our efforts led to the discovery of the 5-azaquinoxaline as a new core for developing this class of compounds. Optimization of the potency and properties of this scaffold generated compound 30, that exhibited potent in vitro SHP2 inhibition and showed excellent in vivo efficacy and pharmacokinetic profile.

Allosteric SHP2 inhibition increases apoptotic dependency on BCL2 and synergizes with venetoclax in FLT3- and KIT-mutant AML

Mutations in the receptor tyrosine kinases (RTKs) FLT3 and KIT are frequent and associated with poor outcomes in acute myeloid leukemia (AML). Although selective FLT3 inhibitors (FLT3i) are clinically effective, remissions are short-lived due to secondary resistance characterized by acquired mutations constitutively activating the RAS/MAPK pathway. Hereby, we report the pre-clinical efficacy of co-targeting SHP2, a critical node in MAPK signaling, and BCL2 in RTK-driven AML. The allosteric SHP2 inhibitor RMC-4550 suppresses proliferation of AML cell lines with FLT3 and KIT mutations, including cell lines with acquired resistance to FLT3i. We demonstrate that pharmacologic SHP2 inhibition unveils an Achilles' heel of RTK-driven AML, increasing apoptotic dependency on BCL2 via MAPK-dependent mechanisms, including upregulation of BMF and downregulation of MCL1. Consequently, RMC-4550 and venetoclax are synergistically lethal in AML cell lines and in clinically relevant xenograft models. Our results provide mechanistic rationale and pre-clinical evidence for co-targeting SHP2 and BCL2 in RTK-driven AML.

Identification of a Novel, Potent, and Orally Bioavailable Guanidine-Based SHP2 Allosteric Inhibitor from Virtual Screening and Rational Structural Optimization for the Treatment of KRAS Mutant Cancers.

Src homology-2 domain containing protein tyrosine phosphatase-2 (SHP2) is a highly attractive therapeutic target for treating Kirsten rat sarcoma viral oncogene (KRAS) mutant cancers. In this work, a series of guanidine-based SHP2 allosteric inhibitors were discovered via virtual screening and rational structural optimization. Notably, lead compound 23 with potent SHP2 inhibitory activity (IC50 = 17.7 nM) effectively inhibited the proliferation, migration, and invasion of MIA PaCa-2 pancreatic cancer cells. Furthermore, compound 23 featured great in vivo pharmacokinetic properties (AUCpo = 4320 nM·h; F = 66.3%) and exhibited significant antitumor efficacy in the MIA PaCa-2 xenograft mouse model. This demonstrates that compound 23 is a potential lead compound for the development of SHP2 allosteric inhibitors to treat KRAS mutant cancers. Moreover, these guanidine-based scaffolds may provide an opportunity to mitigate the potential safety risks of the alkyl amine motif predominately incorporated in current SHP2 allosteric inhibitors.

Allosteric modulation of SHP2: Quest from known to unknown.

Src homology-2 domain-containing protein tyrosine phosphatase-2 (SHP2) is a key regulatory factor in the cell cycle and its activating mutations play an important role in the development of various cancers, making it an important target for antitumor drugs. Due to the highly conserved amino acid sequence and positively charged nature of the active site of SHP2, it is difficult to discover inhibitors with high affinity for the catalytic site of SHP2 and sufficient cell permeability, making it considered an "undruggable" target. However, the discovery of allosteric regulation mechanisms provides new opportunities for transforming undruggable targets into druggable ones. Given the limitations of orthosteric inhibitors, SHP2 allosteric inhibitors have become a more selective and safer research direction. In this review, we elucidate the oncogenic mechanism of SHP2 and summarize the discovery methods of SHP2 allosteric inhibitors, providing new strategies for the design and improvement of SHP2 allosteric inhibitors.

Discovery of a Novel Series of Potent SHP2 Allosteric Inhibitors.

Src homology 2-containing protein tyrosine phosphatase 2 (SHP2) is the first reported nonreceptor oncogenic tyrosine phosphatase connecting multiple signal transduction cascades and exerting immunoinhibitory function through the PD-1 checkpoint receptor. As part of a drug discovery program aimed at obtaining novel allosteric SHP2 inhibitors, a series of pyrazopyrazine derivatives bearing an original bicyclo[3.1.0]hexane basic moiety on the left-hand side region of the molecule were identified. We report herein the discovery process, the in vitro pharmacological profile, and the early developability features of compound 25, one of the most potent members of the series.

Abstract CT184: Preliminary dose escalation results of ERAS-601 in combination with cetuximab in FLAGSHP-1: a phase I study of ERAS-601, a potent and selective SHP2 inhibitor, in patients with previously treated advanced or metastatic solid tumors

Abstract Background: SHP2 is an oncogenic tyrosine phosphatase that transduces receptor tyrosine kinase signaling to the RAS/MAPK pathway via its phosphatase-mediated regulation of guanine nucleotide exchange factors. ERAS-601 is a potent, selective, and orally bioavailable allosteric inhibitor of SHP2. In combination with cetuximab, an antibody that targets epidermal growth factor receptor (EGFR), ERAS-601 has demonstrated robust nonclinical activity in human papillomavirus (HPV)-negative head and neck squamous cell carcinoma (HNSCC) and RAS/RAF wild-type colorectal cancer (CRC) tumors. Method: FLAGSHP-1 is the first-in-human trial of ERAS-601 administered as monotherapy and in combination with other cancer therapies in patients with advanced or metastatic solid tumors. The primary objectives are to characterize the safety profile, determine the maximum tolerated dose (MTD)/recommended dose (RD), and characterize the pharmacokinetics (PK) profile of ERAS-601 as a monotherapy and in combination with other cancer therapies. Secondary objectives include tolerability and antitumor activity in solid tumors. Presented here are results from the combination dose escalation cohorts in which patients received ERAS-601 twice a day for three weeks followed by a one-week break (BID 3/1) in combination with cetuximab (500mg/m2) administered every 2 weeks (Q2W) on a 28-day cycle. Results: As of October 31, 2022, a total of 15 patients with previously treated advanced or metastatic solid tumors received ERAS-601 BID 3/1 at the following dose levels: 20 mg BID 3/1 (n=4), 40 mg BID 3/1 (n=8), or 60 mg BID 3/1 (n=3) in combination with cetuximab. Combination therapy MTD was determined​ to be 40 mg BID 3/1. ERAS-601 Treatment Related Adverse Events (TRAEs) at or below the MTD were all Grade 1 and 2. TRAEs occurring in ≥20% of patients included diarrhea (27%), AST increase (27%), ALT increase (20%), dermatitis acneiform (20%). Grade ≥3 TRAEs included Grade 4 hypokalaemia, Grade 3 diarrhea, platelet count decreased anemia (each 7%); high grade TRAEs were only observed at 60 mg BID 3/1 (above the MTD). Dose limiting toxicities (DLTs) were only observed at the 60mg BID 3/1 dose levels and included Grade 3 platelet count decreased (n=1) and Grade 4 hypokalemia (n=1). Pharmacokinetics of ERAS-601 and cetuximab in combination were generally comparable to historical monotherapy PK values, suggesting lack of drug-drug interaction. The evaluation of clinical activity is still ongoing. Conclusions: ERAS-601 in combination with cetuximab in patients with previously treated advanced or metastatic solid tumors shows promising preliminary safety and tolerability with reversible and manageable TRAEs. Further evaluation in relevant tumor types are ongoing. Citation Format: Meredith McKean, Ezra Rosen, Minal Barve, Tarek Meniawy, Judy Wang, David S. Hong, Jennifer Yang, Zhengrong Li, Roxana Picard, Les Brail, Daniela Vecchio, Thomas John, Ezra Cohen, Gregory Obara, Aparna Parikh. Preliminary dose escalation results of ERAS-601 in combination with cetuximab in FLAGSHP-1: a phase I study of ERAS-601, a potent and selective SHP2 inhibitor, in patients with previously treated advanced or metastatic solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr CT184.

Abstract 4012: Preclinical development of SHP2 allosteric inhibitor ICP-189

Abstract Background: SHP2 is a non-receptor protein tyrosine phosphatase which functions as a convergent signaling node downstream of multiple receptor tyrosine kinases (RTKs), and upstream of RAS to promote oncogenic signaling and tumor growth. SHP2 also mediates PD-1 immune blockade of T cells by binding to the immune receptor tyrosine-based inhibitory motif (ITIM) and immune receptor tyrosine-based switch motif (ITSM) of PD-1. SHP2 has long been considered as a plausible oncology drug target not only as an oncoprotein, but also as an important immune modulator. However, for decades, SHP2 was thought to be "undruggable" due to difficulties in targeting its catalytic site. Recent discovery of allosteric site of SHP2 has inspired a novel approach for SHP2 targeting. Here we report the development of ICP-189, which is a potent, highly selective, and orally bioavailable allosteric inhibitor of SHP2, demonstrated robust efficacies in various in vitro and in vivo RAS/MAPK pathway-driven models as mono-therapeutic agent or in combination with other anti-cancer drugs. Results: ICP-189 inhibits phosphatase activity of SHP2 with IC50 values < 5 nM. In a phosphatase profiling assay, ICP-189 efficiently inhibits the catalytic activity of SHP2, with no significant effects on 21 other tested tyrosine and serine/threonine phosphatases, indicating its high selectivity for SHP2. ICP-189 has demonstrated robust in vitro efficacies in a panel of tumor cell lines bearing activated RTK, RAS, NF1 loss-of-function, or BRAF class III mutations. It has also exhibited synergistic tumor killing effects in combination with EGFR, KRASG12C, MEK and CDK4/6 inhibitors. In a series of in vivo efficacy studies, ICP-189 treatment results in robust tumor growth control of MIA-PaCa-2, KYSE-520 and NCI-H358 xenografts. ICP-189 has also shown strong synergies in tumor killing when combined with MEK inhibitor trametinib, KRASG12C inhibitor sotorasib, EGFR inhibitor osimertinib in xenograft models; and when combined with anti-PD-1 antibody in EMT6 syngeneic tumors. The in vivo efficacy of ICP-189 is well accompanied by pharmacodynamic modulations, where ICP-189 exposure levels correlate with the inhibition of p-ERK and DUSP6 mRNA level in tumors. The pharmacokinetic parameters of ICP-189 are overall favorable, with high oral bioavailability. Nonclinical safety evaluations also exhibit acceptable drug tolerability in SD rats and Beagle dogs. Conclusions: ICP-189 is a novel allosteric inhibitor of SHP2 with broad-spectrum anti-tumor activities as a single agent or in combination with other targeted or immune modulating anti-cancer therapeutics. ICP-189 is now in phase I clinical trial in China and United States. Citation Format: Ruixia Liang, Yingxiang Gao, Fangfang Yang, Yingrui Han, Zuopeng Wang, Richard Liu, Charles Ying Wang, Jason Bin Zhang, Xiangyang Chen, Davy Xuesong Ouyang. Preclinical development of SHP2 allosteric inhibitor ICP-189. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4012.