FDA-approved Tyrosine Kinase Inhibitors Research Articles

Designing Novel BCR-ABL Inhibitors for Chronic Myeloid Leukemia with Improved Cardiac Safety.

Development of tyrosine kinase inhibitors (TKIs) targeting the BCR-ABL oncogene constitutes an effective approach for the treatment of chronic myeloid leukemia (CML) and/or acute lymphoblastic leukemia. However, currently available inhibitors are limited by drug resistance and toxicity. Ponatinib, a third-generation inhibitor, has demonstrated excellent efficacy against both wild type and mutant BCR-ABL kinase, including the “gatekeeper” T315I mutation that is resistant to all other currently available TKIs. However, it is one of the most cardiotoxic of the FDA-approved TKIs. Herein, we report the structure-guided design of a novel series of potent BCR-ABL inhibitors, particularly for the T315I mutation. Our drug design paradigm was coupled to iPSC–cardiomyocyte models. Systematic structure–activity relationship studies identified two compounds, 33a and 36a, that significantly inhibit the kinase activity of both native BCR-ABL and the T315I mutant. We have identified the most cardiac-safe TKIs reported to date, and they may be used to effectively treat CML patients with the T315I mutation.

Abstract GS109: Ponatinib-induced Cardiotoxicity Is Driven By S100A8/A9-NLRP3-IL1β Signaling Mediated Excessive Inflammation

Background: The tyrosine kinase inhibitor (TKI) ponatinib is the oral drug for the treatment of chronic myelogenous leukemia (CML) patients with T315I (gatekeeper) mutation. Pharmacovigilance analysis of FDA and WHO datasets have revealed that ponatinib is the most cardiotoxic agent among all FDA-approved TKIs in a real-world scenario. However, the mechanism of ponatinib-induced cardiotoxicity is unknown. The cardiotoxic effects of ponatinib remained hidden in preclinical studies and were only revealed in phase 2 clinical studies and by the subsequent meta-analysis. The lack of well-optimized mouse models has hampered the in vivo cardio-oncology studies. To this end, here we aimed to investigate the hidden cardiotoxic mechanism of ponatinib and strategies to prevent the cardiotoxic manifestations. Methods: We employed wild-type C57BL/6, cardiovascular (CV) comorbidity models e.g., transverse aortic constriction (TAC)-pressure overload (cardiac comorbidity) and high-fat diet-fed ApoE -/- (vascular comorbidity), to investigate the cardiotoxic mechanism of ponatinib. Echocardiography was performed to assess cardiac function. Comprehensive immune profiling was performed to identify ponatinib-induced immune activation using flow cytometry analysis and cytokine assay. Results: Echocardiographic assessment of ponatinib treated high-fat diet-fed ApoE -/- and pressure overload (PO) murine model showed a significant decline in cardiac function, suggesting the key role of CV-comorbidities in ponatinib-induced cardiomyopathy. A combination of multiple in vitro and in vivo models was employed to delineate the underlying molecular mechanisms. An unbiased RNA-Seq analysis identified the enrichment of dysregulated inflammatory genes, including a multi-fold upregulation of alarmins S100A8/A9 as a top hit in ponatinib-treated hearts. Mechanistically, we demonstrate that ponatinib activates the S100A8/9-TLR4-NLRP3-IL-1β signaling pathway in cardiac and systemic myeloid cells (monocytes and neutrophils), in vitro and in vivo , thereby leading to excessive myocardial and systemic inflammation. Excessive inflammation was central to the cardiac pathology because interventions with broad-spectrum immunosuppressive glucocorticoid dexamethasone or direct NLRP3 inhibitor Cy-09 nearly abolished the ponatinib-induced cardiac dysfunction. Taken together, these findings uncover a novel mechanism of ponatinib-induced cardiac inflammation leading to cardiac dysfunction. Conclusions: These findings uncover a novel mechanism of ponatinib-induced cardiac inflammation leading to cardiac dysfunction. Our results provide critical preclinical data and rationale for a clinical investigation into immunosuppressive interventions to mitigate ponatinib-induced cardiotoxicity.

S-palmitoylation of PCSK9 induces sorafenib resistance in liver cancer by activating the PI3K/AKT pathway.

Sorafenib is currently the first-line treatment for advanced hepatocellular carcinoma (HCC). However, sorafenib resistance remains a significant challenge. Aberrant AKT signaling activation is a crucial mechanism driving sorafenib resistance in HCC. Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays a vital role in antitumor immune responses. In this study, we demonstrate that aberrant PCSK9 upregulation promotes cell proliferation and sorafenib resistance in HCC by inducing AKT-S473 phosphorylation. After palmitoylation at cysteine 600, the binding affinity between PCSK9 and tensin homolog (PTEN) is dramatically increased, inducing lysosome-mediated PTEN degradation and subsequent AKT activation. We identify zinc finger DHHC-type palmitoyltransferase 16 (ZDHHC16) as a palmitoyltransferase that promotes PCSK9 palmitoylation at cysteine 600. We also develop a biologically active PCSK9-derived peptide that competitively inhibits PCSK9 palmitoylation, suppressing AKT phosphorylation and augmenting the antitumor effects of sorafenib in HCC.

A systematic comparison of anti-angiogenesis efficacy and cardiotoxicity of receptor tyrosine kinase inhibitors in zebrafish model

Pathological angiogenesis is fundamental to progression of cancerous tumors and blinding eye diseases. Anti-angiogenic receptor tyrosine kinase inhibitors (TKIs) are in broad use for the treatment of these diseases. With more and more TKIs available, it is a challenge to make an optimal choice. It remains unclear whether TKIs demonstrate similar anti-angiogenesis activities in different tissues. Many TKIs have shown varying degrees of toxic effects that should also be considered in clinical use. This study investigates the anti-angiogenic effects of 13 FDA-approved TKIs on the intersegmental vessels (ISVs), subintestinal vessels (SIVs) and retinal vasculature in zebrafish embryos. The results show that vascular endothelial growth factor receptor TKIs (VEGFR-TKIs) exhibit anti-angiogenic abilities similarly on ISVs and SIVs, and their efficacy is consistent with their IC50 values against VEGFR2. In addition, VEGFR-TKIs selectively induces the apoptosis of endothelial cells in immature vessels. Among all TKIs tested, axitinib demonstrates a strong inhibition on retinal neovascularization at a low dose that do not strongly affect ISVs and SIVs, supporting its potential application for retinal diseases. Zebrafish embryos demonstrate cardiotoxicity after VEGFR-TKIs treatment, and ponatinib and sorafenib show a narrow therapeutic window, suggesting that these two drugs may need to be dosed more carefully in patients. We propose that zebrafish is an ideal model for studying in vivo antiangiogenic efficacy and cardiotoxicity of TKIs.

Disparity of race reporting and representation among US FDA approved tyrosine kinase inhibitors

By Neha K. Reddy, Clark Andersen & 2 more. In this study, we show that in studies on approved tyrosine kinase inhibitors black and hispanic races are consistently underrepresented. To address disparities, future studies should then broaden their populations

Abstract 3336: Preclinical activity of NVL-520 in ROS1-driven cancer models with diverse fusion partners and kinase-domain mutations

Abstract The ROS1 receptor tyrosine kinase can be aberrantly activated by gene rearrangements that generate oncogenic ROS1 kinase fusions. ROS1 fusions have been detected in diverse adult and pediatric cancers including up to 2% of non-small cell lung cancers (NSCLC), 1-9% of cholangiocarcinomas, and 0.5-1% of gliomas and glioblastomas. There are over 50 known fusion partners of ROS1. Notable examples include CD74, EZR, SDC4, and SLC34A2 in NSCLC; GOPC exons 1-3 (short form or GOPC(S)) in cholangiocarcinoma; and GOPC exons 1-7 (long form or GOPC(L)) in glioblastoma. Crizotinib and entrectinib are FDA-approved ROS1 tyrosine kinase inhibitors (TKIs), but clinical emergence of ROS1 resistance mutations S1986F/Y, F2004C/I/V, L2026M, G2032R, and D2033N restricts their therapeutic utility. Due to the diversity of ROS1 fusion partners and kinase-domain mutations, development of novel ROS1 inhibitors that retain potency against fusion variants and resistance mutations would be beneficial to address these clinical needs. NVL-520 is a novel, brain-penetrant ROS1-selective inhibitor that exhibits preclinical activity against ROS1 alterations, including resistance mutations, while also sparing inhibition of TRKB. TRKB inhibition in the central nervous system has been implicated in adverse events observed with FDA-approved dual TRK/ROS1 inhibitor entrectinib and FDA-approved ALK inhibitor lorlatinib. We previously reported the activity of NVL-520 in several cell line and xenograft models bearing CD74-ROS1, EZR-ROS1, and SDC4-ROS1 fusions, with a wild-type kinase domain or a G2032R mutation. Here we report a broader comparative characterization of NVL-520 and other ROS1 inhibitors against a diverse set of ROS1 fusion partners and kinase-domain mutations. NVL-520 showed potent suppression of proliferation and/or ROS1 signaling in Ba/F3, NIH3T3, or human cancer cell lines expressing CD74-, EZR-, SLC34A2-, or GOPC(L)-ROS1 fusions. NVL-520 also retained potent inhibition of Ba/F3 cells expressing ROS1 fusions with F2004C, F2004V, G2101A, or G2032R mutations. To further demonstrate the broad activity of NVL-520, we utilized NIH3T3 cells expressing CD74- or EZR-ROS1 fusions with G2032R or F2004C mutations. NVL-520 robustly suppressed colony formation and downstream effector signaling in the ROS1 G2032R and F2004C resistance mutant context. Lastly, NVL-520 demonstrated inhibition of ROS1 signaling in a human glioblastoma cell line U118MG, which harbors the GOPC(L)-ROS1 fusion. In conclusion, the preclinical profile of NVL-520 supports its potential to address a medical need for patients with a diverse array of ROS1 fusion partners and kinase-domain mutations, both in NSCLC and in other cancers such as glioblastoma. NVL-520 is being evaluated in a Phase 1/2 clinical trial for patients with advanced ROS1-positive NSCLC or other solid tumors (NCT05118789). Citation Format: Anupong Tangpeerachaikul, Clare Keddy, Katelyn Nicholson, Monika Davare, Henry E. Pelish. Preclinical activity of NVL-520 in ROS1-driven cancer models with diverse fusion partners and kinase-domain mutations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3336.

A Concise Review on Tyrosine Kinase Targeted Cancer Therapy

Abstract: The tyrosine kinase (TK) family is considered one of the important family members of the kinase family due to its important role in various cellular processes like cell growth, cell differentiation, apoptosis, etc. Mutation, overexpression, and dysfunction of tyrosine kinase receptors lead to the development of malignancy; thus, they are considered as one of the important targets for the development of anti-cancer molecules. The tyrosine kinase family is majorly divided into two classes; receptor and non-receptor tyrosine kinase. Both of the classes have an important role in the development of tumour cells. Currently, there are more than 40 FDA-approved tyrosine kinase inhibitors, which are used in the treatment of various types of cancers. Tyrosine kinase inhibitors mainly block the phosphorylation of tyrosine residue of the corresponding kinase substrate and so activation of downstream signalling pathways can be inhibited. The promising results of tyrosine kinase inhibitors in solid tumours provide a revolution in oncology research. In this article, we had summarized the role of some important members of the tyrosine kinase family in the development and progression of tumour cells and the significance of tyrosine kinase inhibitors in the treatment of various types of cancer.

Human epidermal growth factor receptor 2 (HER2) and fibroblast growth factor receptor 3 (FGFR3) mutations to reveal biological pathways in urothelial carcinoma.

567 Background: Human epidermal growth factor receptor 2 (HER2) (gene name: ERBB2) is a member of the epidermal growth factor receptor (EGFR) family and when mutated, associated with higher grade and stage of localized bladder cancer. Two HER2-targeted antibody-drug conjugates (ADC), trastuzumab emtansine and trastuzumab deruxtecan, are currently approved by the Food and Drug Administration (FDA) for use in gastric/breast cancers with promising application in urothelial carcinoma. Fibroblast growth factor receptor 3 ( FGFR3) is the target of another FDA-approved tyrosine kinase inhibitor erdafitinib and generally associated with more favorable prognosis as well as upper tract carcinoma. The purpose of this study is to characterize ERBB2 and FGFR3 mutations in a prospectively collected cohort of urothelial cancers. Methods: Patients with localized upper or lower tract urothelial carcinoma diagnosed between 2014 and 2020 who underwent a targeted exome sequencing panel of up to 468 cancer genes were identified. If multiple tumors were sequenced, only the diagnostic specimen was included. Analysis of gene alterations, frequency, and associated co-mutations was performed. Descriptive statistics were used to compare baseline patient characteristics. Results: 381 unique ERBB2 or FGFR3 mutated urothelial carcinoma specimens were included in this study. Of note, ERBB2 and FGFR3 mutations were essentially mutually exclusive and included 122 (66%) ERBB2 mutated tumors and 259 (34%) FGFR3 mutated tumors. Patients with tumors harboring FGFR3 mutations were younger (median 70 years IQR 60-76 vs. 74 years IQR 66-78, p<0.05), while patients with ERBB2 mutated tumors were more likely to be male (85% vs 73%, p<0.05). At the time of diagnosis, ERBB2 tumors were more likely to present with advanced (pT2 or higher) disease compared to FGFR3 mutated tumors (48% vs 24%). ERBB2 mutated tumors were more likely associated with RB1, P53, and ARID1A mutations, while FGFR3 mutated tumors were more likely associated with CDKN2A/B and STAG2 mutations (Table). Conclusions: These data highlight divergent biological pathways for patients with targetable mutations in ERBB2 and FGFR3 and are consistent with prior findings in non-muscle invasive bladder cancer. ERBB2 mutated tumors are associated with male gender, more aggressive pathological features and co-mutations with RB1, P53, and ARID1A.[Table: see text]

Identification of Sorafenib as a Treatment for Type 1 Diabetes.

Th1 cell activation is considered a key mediator of the pathogenesis of type 1 diabetes. Targeting IL-12-induced Th1 cell differentiation seems to be an effective way to block the development of type 1 diabetes. However, given the critical function of Th1 in the immune system, the potential side effects hinder the application of anti-Th1 therapy in the treatment of type 1 diabetes. To identify safe anti-Th1 treatment(s), we screened the FDA-approved tyrosine kinase inhibitor (TKI) drug library using an IL-12-induced Th1 differentiation cell model. We found that among the TKIs with little effect on T cell viability, sorafenib is the top contender for the inhibition of Th1 differentiation. Treatment of NOD mice with sorafenib significantly impeded the development of type 1 diabetes and ameliorated insulitis, which coincided with a specifically decreased accumulation of Th1 cell population in the pancreas but not in peripheral immune organs. Mechanistically, sorafenib indirectly inhibited janus kinase 2 (JAK2) activity and blocked IL-12-induced phosphorylations of JAK2 and signal transducer and activator of transcription 4 (STAT4). Since sorafenib is classified as an FDA-approved drug, it serves as a preliminary lead point for additional experimentation and may be a promising therapy for type 1 diabetes in humans.

Transport and metabolism of tyrosine kinase inhibitors associated with chronic myeloid leukemia therapy: a review.

Imatinib, nilotinib, dasatinib, bosutinib, ponatinib, and asciminib are FDA-approved tyrosine kinase inhibitors (TKIs) for chronic myeloid leukemia (CML), each of which has a specific pharmacological profile. Asciminib has been recently (2021) approved for patients resistant to former TKIs, and because the binding site of this drug (the myristoyl pocket in the ABL1 kinase) is different from that of other TKIs (ATP-binding sites), it is, therefore, effective against T315I mutation of BCR-ABL oncoprotein. All TKIs have a different pharmacological profile due to different chemical structures. Imatinib is the only TKI whose absorption depends on both influx (OCT1 and OATP1A2) and efflux (ABCB1 and ABCG2) transporters, whereas the others rely only on efflux transporters. The efflux of dasatinib is also regulated by ABCC4 and ABCC6 transporters. Nilotinib and ponatinib are transported passively, as no role of transporters has been found in their case. A phenomenon common to all in the metabolic aspect is that the CYP3A4 isoform of CYP450 primarily metabolizes TKIs. Not only does CYP3A4, flavin-containing monooxygenase 3 (FMO3), and uridine 5'-diphospho-glucuronosyltransferase (UGT) also metabolize dasatinib, and similarly, by glucuronidation process, asciminib gets metabolized by UGT enzymes (UGT1A3, UGT1A4, UGT2B7, and UGT2B17). Additionally, the side effects of TKIs are categorized as hematological (thrombocytopenia, neutropenia, anemia, and cardiac dysfunction) and non-hematological (diarrhea, nausea, vomiting, pleural effusion, and skin rash). However, few toxicities are drug-specific, like degradation of biomolecules by ponatinib-glutathione (P-GSH) conjugates and clinical pancreatitis (dose-limited toxicity and manageable by dosage alterations) are related to ponatinib and asciminib, respectively. This review focuses on the pharmacokinetics of approved TKIs related to CML therapy to comprehend their specificity, tolerability, and off-target effects, which could help clinicians to make a patient-specific selection of CML drugs by considering concomitant diseases and risk factors to the patients.

Protein Tyrosine Phosphatase Biochemical Inhibition Assays.

Disturbance of the dynamic balance between protein tyrosine phosphorylation and dephosphorylation, modulated by protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs), is known to be crucial for the development of many human diseases. The discovery of agents that restore this balance has been the subject of many drug research efforts, most of which have focused on tyrosine kinase inhibitors (TKIs), resulting in the development of more than 50 FDA-approved TKIs during the past two decades. More recently, accumulating evidence has suggested that members of the PTP superfamily are also promising drug targets, and efforts to discover tyrosine phosphatase inhibitors (TPIs) have increased dramatically. Here, we provide protocols for determining the potency of TPIs in vitro. We focus on the use of fluorescence-based substrates, which exhibit a dramatic increase in fluorescence emission when dephosphorylated by the PTP, and thus allow setting up highly sensitive and miniaturized phosphatase activity assays using 384-well or 1536-well microplates and a continuous (kinetic) assay format. The protocols cover PTP specific activity assays, Michaelis-Menten kinetics, dose-response inhibition assays, and dose-response data analysis for determining IC 50 values. Potential pitfalls are also discussed. While advanced instrumentation is utilized for compound spotting and liquid dispensing, all the assays can be adapted to existing equipment in most laboratories. Assays are described for selected PTP drug targets, including SHP2 ( PTPN11 ), PTP1B ( PTPN1 ), STEP ( PTPN5 ), and VHR ( DUSP3 ). However, all protocols are applicable to members of the PTP enzyme family in general. Graphical abstract.

Abstract P244: NVL-655 exhibits antitumor activity in lorlatinib-resistant and intracranial models of ALK-rearranged NSCLC

Abstract ALK receptor tyrosine kinase can be aberrantly activated by gene rearrangement or point mutation to drive tumor cell proliferation, survival, and metastasis. ALK rearrangements are detected in up to 5% of advanced non-small cell lung cancer (NSCLC), and up to 40% of patients present with brain metastases at diagnosis. Crizotinib, ceritinib, alectinib, brigatinib, and lorlatinib are FDA-approved tyrosine kinase inhibitors for ALK-positive NSCLC. However, durability of response to these treatments is partly limited by mutations in ALK that confer resistance. The G1202R solvent front mutation is commonly observed in patients that have progressed on crizotinib, ceritinib, alectinib, or brigatinib. Patients with tumors harboring G1202R have responded to lorlatinib, but many have relapsed after acquiring compound mutations such as G1202R/L1196M and G1202R/G1269A. Another challenge with lorlatinib is central nervous system (CNS) adverse events attributed to inhibition of tropomyosin receptor kinase B (TRKB), a kinase structurally related to ALK. NVL-655 is a novel preclinical brain-penetrant ALK inhibitor with selectivity over TRKB. We previously reported that NVL-655 inhibits ALK G1202R, G1202R/L1196M, G1202R/G1269A, and G1202R/L1198F in vitro; has favorable kinome and ALK-vs-TRKB selectivity profiles; and shows antitumor activity in a Ba/F3 EML4-ALK variant 1 (v1) G1202R/L1196M xenograft model. Here we report results of a broader preclinical characterization of NVL-655 across ALK models, including an intracranial model. NVL-655 was observed to induce regression in a HIP1-ALK patient-derived xenograft model, an EML4-ALK v1 human cancer cell line-derived model (NCI-H3122), and Ba/F3 xenograft models expressing EML4-ALK v1 G1202R and G1202R/G1269A. Pharmacodynamic (PD) biomarker analyses supported in vivo ALK inhibition by NVL-655. Furthermore, NVL-655 was observed to reduce tumor size and prolong survival by more than 4-fold in a mouse intracranial tumor model of Ba/F3 EML4-ALK v1 G1202R/L1196M luciferase. In conclusion, NVL-655 has a preclinical profile that we believe supports its potential to address a medical need for patients with ALK-positive disease, including those with G1202R compound mutations. We believe the findings presented here support the evaluation of NVL-655 for the treatment of patients with ALK-driven disease. Citation Format: Anupong Tangpeerachaikul, Amit Deshpande, Nancy E. Kohl, Joshua C. Horan, Henry E. Pelish. NVL-655 exhibits antitumor activity in lorlatinib-resistant and intracranial models of ALK-rearranged NSCLC [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P244.

Abstract P234: ORIC-114, an orally bioavailable, irreversible kinase inhibitor, has superior brain penetrant properties and enhanced potency in preclinical studies of HER2-positive breast cancer

Abstract Amplification of human epidermal growth factor receptor 2 (HER2) is an oncogenic driver found in approximately 25% of breast cancer. Despite the arsenal of HER2-directed therapies available to patients, more than 50% of patients with HER2 amplification eventually develop central nervous system (CNS) metastases over the course of their disease indicating a clear medical need for brain penetrant therapies in this patient population. ORIC-114 is a brain penetrant, orally bioavailable, irreversible small molecule inhibitor that was designed to target exon20 insertions in epidermal growth factor receptor (EGFR) and HER2. ORIC-114 is highly selective for the EGFR/HER2 family of receptors, reducing the risk for off-target kinase liabilities. In biochemical assays, ORIC-114 displayed low nanomolar potency on HER2. To explore the application of ORIC-114 in the HER2-amplified tumor setting, a cell viability screen was performed against a panel of human breast cancer lines containing both HER2-amplified and non HER2-amplified cell lines. ORIC-114 demonstrated greater than 100-fold enhanced cellular potency on HER2-amplified cancer cell lines relative to non-amplified cancer cell lines. Notably, ORIC-114 cellular EC50s in HER2-amplified breast cancer cell lines were below 30 nM and more potent than both lapatinib and tucatinib, two FDA-approved tyrosine kinase inhibitors for the treatment of HER2-positive breast cancer. ORIC-114 was designed to incorporate physicochemical properties suitable to cross the blood-brain barrier and has exhibited good brain penetration across multiple preclinical species. To further investigate the brain penetrant attributes of ORIC-114 in the context of HER2-positive breast cancer with brain metastases, key features were assessed relative to tucatinib, which has demonstrated clinical efficacy in this setting. In contrast to tucatinib, ORIC-114 displayed minimal impact on efflux transporters as it was only a weak substrate for P-glycoprotein (P-gp) and was not a substrate for breast cancer associated protein (BCRP) in vitro. In addition, ORIC-114 demonstrated superior in vivo brain penetration relative to tucatinib as measured by free brain-to-plasma ratio in mouse. Consequently, ORIC-114 free brain concentrations in rodents were greater than tucatinib, even when the active metabolites of tucatinib were considered. Taken together, these data further establish ORIC-114 as a selective, irreversible, and brain penetrant EGFR/HER2 inhibitor, making it a promising therapeutic candidate for development in patients with HER2-positive tumors including those with CNS metastases. A Clinical Trial Application for ORIC-114 is anticipated in the second half of 2021. Citation Format: Melissa R. Junttila, Jason E. Long, Robert Warne, Sunghwan Kim, Younho Lee, Hwan Kim, Juhee Kang, Jiyoon Seok, Jihye Yoo, Youngyi Lee, Dong-Hyuk Seo Seo, Jung Beom Son, Daekwon Kim, Hwan Geun Choi, Nam Doo Kim, Tatiana Zavorotinskaya, Chelsea Chan, Matthew Panuwat, Jessica Sun, Jae H. Chang, Lori S. Friedman. ORIC-114, an orally bioavailable, irreversible kinase inhibitor, has superior brain penetrant properties and enhanced potency in preclinical studies of HER2-positive breast cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P234.

In Vitro and In Vivo Inhibition of MATE1 by Tyrosine Kinase Inhibitors.

The membrane transport of many cationic prescription drugs depends on facilitated transport by organic cation transporters of which several members, including OCT2 (SLC22A2), are sensitive to inhibition by select tyrosine kinase inhibitors (TKIs). We hypothesized that TKIs may differentially interact with the renal transporter MATE1 (SLC47A1) and influence the elimination and toxicity of the MATE1 substrate oxaliplatin. Interactions with FDA-approved TKIs were evaluated in transfected HEK293 cells, and in vivo pharmacokinetic studies were performed in wild-type, MATE1-deficient, and OCT2/MATE1-deficient mice. Of 57 TKIs evaluated, 37 potently inhibited MATE1 function by >80% through a non-competitive, reversible, substrate-independent mechanism. The urinary excretion of oxaliplatin was reduced by about 2-fold in mice with a deficiency of MATE1 or both OCT2 and MATE1 (p < 0.05), without impacting markers of acute renal injury. In addition, genetic or pharmacological inhibition of MATE1 did not significantly alter plasma levels of oxaliplatin, suggesting that MATE1 inhibitors are unlikely to influence the safety or drug-drug interaction liability of oxaliplatin-based chemotherapy.

Carfilzomib Enhances the Suppressive Effect of Ruxolitinib in Myelofibrosis.

Simple SummaryMyelofibrosis (MF) is a progressive myeloproliferative neoplasm with tendency towards leukemic transformation and has the poorest prognosis amongst the Philadelphia-negative classical myeloproliferative neoplasms (MPN). Ruxolitinib, the first FDA-approved JAK1/2 tyrosine kinase inhibitor, is efficient in reducing spleen size and improving patient symptoms, but it has not been shown to eradicate the MF clone. In this study, using functional genomics techniques, we identified the proteasome family as an additional therapeutic target and demonstrated that inhibition of the proteasome family by carfilzomib in combination with ruxolitinib enhanced suppression of primary MF cells in vitro.As the first FDA-approved tyrosine kinase inhibitor for treatment of patients with myelofibrosis (MF), ruxolitinib improves clinical symptoms but does not lead to eradication of the disease or significant reduction of the mutated allele burden. The resistance of MF clones against the suppressive action of ruxolitinib may be due to intrinsic or extrinsic mechanisms leading to activity of additional pro-survival genes or signalling pathways that function independently of JAK2/STAT5. To identify alternative therapeutic targets, we applied a pooled-shRNA library targeting ~5000 genes to a JAK2V617F-positive cell line under a variety of conditions, including absence or presence of ruxolitinib and in the presence of a bone marrow microenvironment-like culture medium. We identified several proteasomal gene family members as essential to HEL cell survival. The importance of these genes was validated in MF cells using the proteasomal inhibitor carfilzomib, which also enhanced lethality in combination with ruxolitinib. We also showed that proteasome gene expression is reduced by ruxolitinib in MF CD34+ cells and that additional targeting of proteasomal activity by carfilzomib enhances the inhibitory action of ruxolitinib in vitro. Hence, this study suggests a potential role for proteasome inhibitors in combination with ruxolitinib for management of MF patients.

Novel Therapeutics in Radioactive Iodine-Resistant Thyroid Cancer.

Iodine-resistant cancers account for the vast majority of thyroid related mortality and, until recently, there were limited therapeutic options. However, over the last decade our understanding of the molecular foundation of thyroid function and carcinogenesis has driven the development of many novel therapeutics. These include FDA approved tyrosine kinase inhibitors and small molecular inhibitors of VEGFR, BRAF, MEK, NTRK and RET, which collectively have significantly changed the prognostic outlook for this patient population. Some therapeutics can re-sensitize de-differentiated cancers to iodine, allowing for radioactive iodine treatment and improved disease control. Remarkably, there is now an FDA approved treatment for BRAF-mutated patients with anaplastic thyroid cancer, previously considered invariably and rapidly fatal. The treatment landscape for iodine-resistant thyroid cancer is changing rapidly with many new targets, therapeutics, clinical trials, and approved treatments. We provide an up-to-date review of novel therapeutic options in the treatment of iodine-resistant thyroid cancer.

The nonreceptor tyrosine kinase SRMS inhibits autophagy and promotes tumor growth by phosphorylating the scaffolding protein FKBP51.

Nutrient-responsive protein kinases control the balance between anabolic growth and catabolic processes such as autophagy. Aberrant regulation of these kinases is a major cause of human disease. We report here that the vertebrate nonreceptor tyrosine kinase Src-related kinase lacking C-terminal regulatory tyrosine and N-terminal myristylation sites (SRMS) inhibits autophagy and promotes growth in a nutrient-responsive manner. Under nutrient-replete conditions, SRMS phosphorylates the PHLPP scaffold FK506-binding protein 51 (FKBP51), disrupts the FKBP51-PHLPP complex, and promotes FKBP51 degradation through the ubiquitin-proteasome pathway. This prevents PHLPP-mediated dephosphorylation of AKT, causing sustained AKT activation that promotes growth and inhibits autophagy. SRMS is amplified and overexpressed in human cancers where it drives unrestrained AKT signaling in a kinase-dependent manner. SRMS kinase inhibition activates autophagy, inhibits cancer growth, and can be accomplished using the FDA-approved tyrosine kinase inhibitor ibrutinib. This illuminates SRMS as a targetable vulnerability in human cancers and as a new target for pharmacological induction of autophagy in vertebrates.

113-OR: Identification of Sorafenib for the Treatment of Type 1 Diabetes

Type 1 diabetes (T1D) is an immune-mediated disease characterized by impairment of pancreatic beta cells. To date, a comprehensive cure is not available. Th1 cell activation is considered a key mediator of the pathogenesis of T1D. IL-12-induced STAT4 activation is a paramount signaling pathway to instigate Th1 cell differentiation. Targeting IL-12-induced Th1 cell differentiation seems to be an effective way to block the development of T1D. However, given the critical function of Th1 in the immune system, the potential side effects hinder the application of anti-Th1 therapy in the treatment of T1D. To identify safe anti-Th1 treatment(s), we screened the FDA-approved tyrosine kinase inhibitor (TKI) drug library using an IL-12-induced Th1 differentiation cell model. We found that sorafenib, an oral anti-cancer drug, is a top contender for inhibition of Th1 differentiation relative to induced toxicity. Sorafenib inhibited IL-12-induced Th1 cell differentiation in a dose-dependent manner without any change of CD4+ T-cell viability. Treatment of NOD mice with sorafenib significantly impeded the development of T1D and ameliorated insulitis, which coincided with a specifically decreased aggregate of Th1 cell population in pancreas but not in peripheral immune organs. Inflammatory cytokines and Th1 signature transcription factor Tbet mRNA expression in pancreas were decreased in sorafenib-treated NOD mice compared to vehicle-treated NOD mice. Mechanistically, sorafenib directly inhibited JAK2 activity and blocked IL-12-induced phosphorylations of JAK2 and STAT4. In conclusion, sorafenib administration inhibits the development of T1D by suppressing IL-12b/JAK2/STAT4 signaling-mediated Th1 cell differentiation specifically in pancreas in NOD mice. Since sorafenib is classified as an FDA-approved drug, it serves as a preliminary lead point for additional experimentation and may be a promising therapeutic for T1D in humans. Disclosure Q. Zeng: None. J. Song: None. X. Sun: None. D. Wang: None. Y. Xiao: None. Z. Zhou: None. T. Deng: None.

Dosing, drug reduction, drug interruption, and drug discontinuation rates among U.S. FDA approved tyrosine kinase inhibitors.

3112 Background: The advent of tyrosine kinase inhibitors (TKIs) has altered the therapeutic landscape of multiple hematological and solid malignancies. FDA approved starting doses of TKIs are based on the recommended phase 2 dose (RP2D) in clinical trials. Since many of these drugs are continuously dosed, ongoing toxicities may lead to drug reductions and drug discontinuations. Hence in practice, many patients are started on lower doses due to tolerability concerns or are dose-reduced subsequently for toxicity. Herein, we assessed the dosing, drug reduction rates, and drug discontinuation rates among FDA approved TKIs. Methods: We established a database of all FDA approved TKIs from the FDA online label repository. We extracted descriptive data for indications and usage, type of approval, approval dosage, dose reduction recommendation, median age, dose reduction rates, drug discontinuation rates, dose modification, warnings, adverse reactions, clinical trial experience, and geriatric use above 65 yrs and 75 yrs. Results: TKIs were approved for 143 different indications, ranging from 1 indication to 11 indications (eg. Imatinib) from data arising from 7 patients to 2816 patients for a specific indication. Among all TKIs, median dose was 150 mg and average dose was 237 mg; 34 (23.8%) were approved bid vs 71 (49.7%) qd. Specifically for oncology, 54 indications were biomarker based (eg. EGFR mutant NSCLC) and 52 were non-biomarker based for specific diseases (eg. metastatic RCC). Among approved indications range of dose reduction rate (DRR), drug interruption rates (DIR), drug discontinuations rates (DDR) were 0.80-89%, 3%-89%, and 1-39% respectively. Most common reasons for DRR, DIR, and DDR were diarrhea, fatigue, nausea, vomiting, hepatotoxicity, rash, and hypertension. Geriatric use was listed in 99 indications ( &gt; 65 yrs, 6-68%; &gt; 75 yrs, 0.50-24%). Patient reported outcomes were not available. Conclusions: TKIs have a variable dose reduction and drug discontinuation rate. Clinical trials should evaluate multiple dosing regimens and schedules to lessen the toxicity burden and improve QOL in patients. Future studies are warranted to look into flat dosing vs alternative dosing, like weight-based dosing for TKIs, and to report patient reported outcomes.

Impact of immune checkpoint inhibitor (CPI) and EGFR tyrosine kinase inhibitor (TKI) sequence on time to treatment failure (TTF) among EGFR plus NSCLC treated in a community-based cancer research network.

9099 Background: The development of CPIs and driver-targeted TKIs has transformed the treatment of NSCLC and increased survival rates. However, the role of CPIs in patients with oncogenic-driven NSCLC remains an area of investigation. We sought to examine the impact of CPI sequence on treatment response among patients with oncogenic-driver mutation-positive NSCLC. Methods: Patients with NSCLC being treated within the Sarah Cannon Research Institute network were identified through Genospace, Sarah Cannon’s clinico-genomic analytics platform. Advanced stage oncogenic-driven tumors (driver+) were defined as those with a record of receiving an FDA-approved TKI targeting EGFR, ALK, RET, ROS1, NTRK, MET, or BRAF. Kaplan-Meier estimates were used to examine TTF (defined as time from therapy start to start of next therapy, death, or loss to follow-up) and overall survival (OS). Results: We identified 12,352 patients with lung cancer and available therapy data (2005-2020), including 2,270 (18%) driver+ patients. Eleven percent (N=245) of driver+ patients received a CPI, including 120 (49%) with CPI prior to TKI, 122 (50%) with CPI post TKI, and 3 (1%) who received CPI both pre and post TKI. The CPI TTF was significantly longer for those who received CPI post TKI compared to those who received it prior (Table). EGFR+ tumors accounted for 82% (N=1,867) of driver+ patients, 10% of whom (N=188) received a CPI. Of the EGFR+/CPI+ patients, 78 patients (41%) received CPI prior to TKI, 107 (57%) received CPI post TKI, and 3 (2%) received CPI both pre and post TKI. EGFR+ tumors exposed to a CPI post TKI had a longer CPI TTF compared to patients who received it prior (Table). In contrast, there was no difference in length of benefit from TKI if it was received pre vs. post CPI (Table). There was also no difference in OS based on sequence of TKI and CPI (p=0.88). Larger sample sizes are needed for analysis of additional driver-stratified cohorts. Conclusions: Patients with oncogenic-driven NSCLC benefited from CPI longer when it was administered after TKI compared to before. Importantly, therapy sequence only affected length of benefit from CPIs and did not affect length of benefit from TKIs. This effect was present in EGFR+ NSCLC, but sample sizes were too small to determine if the same is true for other oncogenic-drivers. Therapy sequence had no impact on OS, indicating the presence of additional clinical, therapeutic, and/or genomic factors contributing to disease progression. Continued research is needed to better understand markers of CPI response in driver+ NSCLC.[Table: see text]