Molecule Inhibitor Of Receptor Tyrosine Kinases Research Articles

A multicenter real-world study on the efficacy and safety of anlotinib-based treatment for metastatic breast cancer.

e13120 Background: Anlotinib is a multi-targeted small molecule receptor tyrosine kinase (RTK) inhibitor that inhibits angiogenesis. There is only one phase II study on the use of anlotinib in advanced breast cancer (MBC). Therefore, this study aims to analyze its efficacy and safety in the treatment of BC in the real world. It has been approved for the treatment of advanced non-small cell lung cancer and soft tissue sarcoma. There is limited research on the use of anlotinib in advanced breast cancer (MBC). Methods: This study retrospectively analyzed the clinical data of MBC patients who received anlotinib treatment at four domestic centers from January 2021 to December 2023. The primary endpoint was progression-free survival (PFS), and secondary endpoints included overall survival (OS), objective response rate (ORR), disease control rate (DCR), and safety. Kaplan-Meier analysis was used to analyze PFS and OS, and Cox regression model was used to analyze the hazard ratios (HRs) of anlotinib-based treatment on PFS and OS in different subgroups of patients. A p-value <0.05 was considered statistically significant. Results: A total of 153 MBC patients receiving anlotinib-based treatment were included from four centers. The median age was 51 years (range: 22-76), and the median number of prior lines of therapy was 3. The median PFS was 7.7 months (range: 5.2-10.1 months), and the median OS was 28.0 months (range: 21.4-34.9 months). The median ORR and DCR were 19.6% and 60.1%, respectively. The ORR for HR+/HER2- and triple-negative breast cancer patients was 11.6% and 28.8%, respectively, DCR for HR+/HER2- and triple-negative breast cancer (TNBC) patients was 55.8% and 59.6%, respectively. The median PFS was 9.0 months (range: 6.0-11.9 months) for HR+/HER2- patients and 5.3 months (range: 3.5-7.0 months) for TNBC patients, while the median OS was 33.0 months (range: 24.4-41.5 months) and 14.0 months (range: 9.5-18.4 months), respectively. In the subgroup analysis, age <60 years, initial stage IV disease, Ki67≤60%, and treatment with PD-L1 monoclonal antibodies-based regimen were associated with PFS benefit. ECOG <2 and treatment with PD-L1 monoclonal antibodies-based regimen were associated with prolonged OS. Among the 31 patients with brain metastases receiving anlotinib treatment, 11 had active brain metastases and 20 had stable brain metastases. The median PFS was 8.0 months. The intracranial ORR was 12.9%, and the intracranial DCR was 61.3%. No serious adverse events or treatment-related deaths occurred. Grade I/II adverse reactions included hand-foot syndrome (22.2%) and fatigue (19.6%), while grade III/IV adverse reactions included fatigue (6.5%) and decreased neutrophil count (5.2%). Three patients required dose reduction due to intolerable adverse reactions, and nine patients discontinued treatment. Conclusions: Anlotinib demonstrates good antitumor activity and safety in the treatment of MBC. When combined with chemotherapy or immunotherapy, it can improve PFS and OS without significantly increasing toxicity. In particular, it shows promising intracranial ORR and PFS in patients with brain metastases. Clinical trial information: NCT04541420 .

P11.58.A Case of a complex neurocutaneous syndrome characterized by extensive peripheral nerve sheath tumors and somatic ERBB2 mutation

Abstract Schwannomatosis is a rare genetic tumor predisposition syndrome characterized by the presence of multiple non-intradermal schwannomas and the definitive absence of vestibular nerve involvement. Though considered benign, the burden of tumors can cause significant morbidity in the form of motor dysfunction and refractory neuropathic pain. Treatment is focused on mitigating these symptoms, which includes resection of offending tumors when feasible and anti-angiogenesis therapy with bevacizumab. Options for targeted medical therapies are lacking. Schwannomatosis is molecularly distinct from the other neurofibromatoses and by definition lacks constitutional mutations in NF1 and NF2. Instead, constitutional mutations in SMARCB1 or LZTR1 are often the “first hit” in tumorigenesis. Activating mutations in ERBB2 (also designated HER2) have been identified as oncogenic drivers in peripheral nerve sheath tumors in patients who lack these typical constitutional tumor suppressor gene mutations. Here we report a case of extensive peripheral nerve sheath tumors in the setting of apparent somatic mosaicism of an ERBB2 mutation. A 48-year-old man with history of chronic back pain presented with diffuse enlarging soft tissues masses primarily involving the left neck and occiput. Examination revealed areas of cutaneous heterogeneous hyperpigmentation, decreased muscle bulk and dorsiflexor weakness in the bilateral lower extremities, and steppage gait. Neuroimaging showed extensive T2 hyperintense, mildly enhancing masses within the bilateral thoracic and lumbar spine neuroforamina, intercostal nerves, paraspinal musculature, and lumbosacral plexus. Tissue from two separate tumor sites was morphologically consistent with schwannoma with some features of neurofibroma. Immunohistochemistry revealed partial loss of staining for SMARCB1. Whole exome sequencing (WES) on blood and tumor tissue did not show pathogenic germline or somatic variants for NF1, NF2, SMARCB1, LZTR1, or an array of tumor predisposition syndromes. WES on tumor tissue from both sites however did reveal a somatic ERBB2 variant (p.D769Y), suggesting mosaicism. ERBB2 D769Y has previously been classified as an activating mutation that confers sensitivity to some small molecule receptor tyrosine kinase inhibitors. Patients with ERRB2-mutated peripheral nerve sheath tumors may have broader therapeutic options in the variety of available tyrosine kinase inhibitors studied in other cancers.

EPEN-12. Sunitinib induces apoptosis-mediated cytotoxicity in PFA ependymoma

Abstract Ependymoma (EPN) has been previously shown to be selectively targeted by three classes of FDA-approved chemotherapy drugs: fluorinated pyrimidines, retinoids, and a subset of small molecule receptor tyrosine kinase inhibitors (RTKIs). We have identified sunitinib malate as an RTKI with ependymoma selectivity, in addition to previously identified ependymoma-selective RTKIs axitinib, imatinib, and pazopanib. Sunitinib—which targets VEGFR, PDGFR and c-kit—elicited unexpectedly high levels of cytotoxic apoptosis (caspase 3/7 cleavage) in EPN PFA cell lines harboring high-risk chromosome 1q gain and 6q loss. In this in-vitro screen of 100+ FDA-approved chemotherapy drugs, sunitinib was the only RTKI in the top five most cytotoxic drugs, a group that included idarubicin HCl, topotecan HCl, daunorubicin HCl, and doxorubicin. Additionally, sunitinib exhibited comparable caspase 3/7 cleavage levels in normoxia and hypoxia, suggesting that this therapy would be as effective in treatment of tumors with potentially resistant hypoxic necrotic cores. The effect of sunitinib on EPN cellular proliferation was tracked visually using Incucyte cell imaging technology, demonstrating consistent dose-dependent inhibition of proliferation. Sunitinib achieved more acute upregulation of apoptosis than axitinib, an EPN-selective RTKI currently being studied in preclinical models. A prior phase II trial of sunitinib in pediatric EPN and high-grade glioma showed that treatment was well tolerated but with no clinical benefit as a monotherapy. However, given encouraging clinical results of combining sunitinib with radiation, our ongoing preclinical studies of sunitinib in EPN are being conducted in the context of radiation which is standard treatment for EPN. Sunitinib presents a promising treatment to an intractable pediatric brain tumor that exhibits high rates of relapse and morbidity in affected individuals.

8MO The efficacy and safety of TQ-B3101 monotherapy in the first-line treatment in patients with ROS1-positive non-small cell lung cancer

TQ-B3101 is a novel small molecule receptor tyrosine kinase inhibitor, which targets to ALK, ROS1 and MET. Preclinical studies showed that it had a good tumor inhibition activity and duration. This study aims to evaluate the efficacy and safety of TQ-B3101 monotherapy in the first-line treatment in patients with ROS1-positive non-small cell lung cancer (NSCLC).

A patent review on efficient strategies for the total synthesis of pazopanib, regorafenib and lenvatinib as novel anti-angiogenesis receptor tyrosine kinase inhibitors for cancer therapy.

Angiogenesis is an important and interesting scientific subject in the area of malignant tumours. Current research importance and interest are directed in connection to blood microvessels in cancer cell proliferation, tumour growth, and metastasis. Tyrosine kinases have been intensely implicated as therapeutic targets that affect the angiogenic process in tumour growth. In the last decades, targeting angiogenesis has led to achievements in the therapy of different carcinomas by different mechanisms, such as the utilization of anti-angiogenic small molecule receptor tyrosine kinase inhibitors. In the current review, we aim to track the advancements in the total synthesis of three receptor tyrosine kinase inhibitors (pazopanib, regorafenib and lenvatinib). This review surveys different synthetic routes for these three approved drugs (pazopanib, regorafenib and lenvatinib) which were previously published as patents (2014-2021). The purity of medicines is a very important factor during manufacturing so we have decided to review the purification process of these anticancer medicines as well. It should be noted that the different patents may have reported some procedures with different yields and purities for the synthesis of desired drug and their intermediates. In order to simplify the understanding of the contents of this review article, only the best results reported in each of these patents are reported for the synthesis of desired drug and their intermediates.

Anti-Angiogenic Therapy: Albumin-Binding Proteins Could Mediate Mechanisms Underlying the Accumulation of Small Molecule Receptor Tyrosine Kinase Inhibitors in Normal Tissues with Potential Harmful Effects on Health.

Simple SummaryIn the last five decades the tumor microvascular endothelium has been, and still remains, an object of sustained interest in biomedical research. This interest is undoubtedly connected with the importance of blood microvessels in cancer cell proliferation, tumor growth, and metastasis. Depriving a tumor of its oxygen and nutrients by preventing the formation of new vessels with anti-angiogenic drugs including small molecule receptor tyrosine kinase inhibitors (RTKIs) is a common treatment in oncology. However, resistance to treatment, insufficient efficacy, and high toxicity limit the success of this antivascular therapy. Cellular and molecular mechanisms mediated by several albumin-binding proteins (ABPs) expressed in normal tissues and organs seem to be responsible for the side effects and toxicity associated with this type of anti-angiogenic therapy.Anti-angiogenics currently used in cancer therapy target angiogenesis by two major mechanisms: (i) neutralizing angiogenic factors or their receptors by using macromolecule anti-angiogenic drugs (e.g., therapeutic antibodies), and (ii) blocking intracellularly the activity of receptor tyrosine kinases with small molecule (Mr < 1 kDa) inhibitors. Anti-angiogenics halt the growth and spread of cancer, and significantly prolong the disease-free survival of the patients. However, resistance to treatment, insufficient efficacy, and toxicity limit the success of this antivascular therapy. Published evidence suggests that four albumin-binding proteins (ABPs) (gp18, gp30, gp60/albondin, and secreted protein acidic and cysteine-rich (SPARC)) could be responsible for the accumulation of small molecule receptor tyrosine kinase inhibitors (RTKIs) in normal organs and tissues and therefore responsible for the side effects and toxicity associated with this type of cancer therapy. Drawing attention to these studies, this review discusses the possible negative role of albumin as a drug carrier and the rationale for a new strategy for cancer therapy based on follicle-stimulating hormone receptor (FSHR) expressed on the luminal endothelial cell surface of peritumoral blood vessels associated with the major human cancers. This review should be relevant to the audience and the field of cancer therapeutics and angiogenesis/microvascular modulation-based interventions.

Diarrhea Induced by Small Molecule Tyrosine Kinase Inhibitors Compared With Chemotherapy: Potential Role of the Microbiome.

Small molecule receptor tyrosine kinase inhibitors (SM-TKIs) are among a group of targeted cancer therapies, intended to be more specific to cancer cells compared with treatments, such as chemotherapy, hence reducing adverse events. Unfortunately, many patients report high levels of diarrhea, the pathogenesis of which remains under investigation. In this article, we compare the current state of knowledge of the pathogenesis of chemotherapy-induced diarrhea (CID) in comparison to SM-TKI–induced diarrhea, and investigate how a similar research approach in both areas may be beneficial. To this end, we review evidence that both treatment modalities may interact with the gut microbiome, and as such the microbiome should be investigated for its ability to reduce the risk of diarrhea.

Gilteritinib: First Global Approval.

Gilteritinib (Xospata®) is an orally available small molecule receptor tyrosine kinase inhibitor developed by Astellas Pharma in collaboration with Kotobuki Pharmaceutical for the treatment of acute myeloid leukaemia (AML) harbouring FMS-like tyrosine kinase 3 (FLT3) mutations. Gilteritinib inhibits FLT3 (STK1 or FLK2), AXL (UFO or JTK11) and anaplastic lymphoma kinase (ALK or CD246). Gilteritinib inhibits FLT3 signalling in cells expressing FLT3 internal tandem duplication (ITD), tyrosine kinase domain mutation FLT3-D835Y and the double mutant FLT3-ITD-D835Y, thereby inducing apoptosis. Gilteritinib also binds to and inhibits the wild-type and mutated forms of ALK, resulting in reduced tumour cell proliferation in cancer cell types that overexpress the mutation. Gilteritinib is approved in Japan for the treatment of relapsed or refractory AML with FLT3 mutation. Recently, it was also approved in the USA for the treatment of adult patients who have relapsed or refractory AML with a FLT3 mutation, as detected by an FDA-approved test. Clinical development of gilteritinib is underway in several countries worldwide. Development for non-small cell lung cancer and solid tumours has been discontinued.

First-in-human study of DS-6051b in patients (pts) with advanced solid tumors (AST) conducted in the US.

2514Background: DS-6051b is an oral, small molecule receptor tyrosine kinase inhibitor with high affinity for ROS1 and NTRK kinases. Preclinical studies demonstrated activity against tumors harbori...

Abstract 2070: HMGB1 governs p53 to autophagic degradation via its nucleus-to-cytoplasm transport

Abstract P53 is under exquisitely fine regulation and acts as a transcription factor that regulates the expression of thousands of genes that control apoptosis, necroptosis, ferrotosis, cell cycle arrest, senescence, metabolism and fertility. Regulation of p53 turnover is essential not only for the response to chemotherapeutic drugs or radiation in cancer cell but also to keep p53 activity under control in a normal cell. Moreover, .p53 is found to be overactivated in various diseases including idiopathic pulmonary fibrosis (IPF), alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD). Promoting hyperactivated-p53 degradation can combat these diseases. However, the strategies that based on known proteasome-dependent degradation only can stabilize the expression level of p53 such as nutlins (inhibit the interaction between mdm2 and tumor suppressor p53). Autophagy-lysosomal degradation is the other pathway for controlling cellular protein stability. More and more researches have established that numerous proteins can be degraded through both proteasome and autophagy-lysosome pathways. However, very little is known to date about p53 turnover through autophagy-lysosome pathway. Here we discover that the activation of p53 autophagic degradation during an oral small molecule receptor tyrosine kinase inhibitor sunitinib in p53 wt cancer cells and normal cells. Mechanistically, the nucleus-to-cytoplasm shift is essential for the autophagic degradation of p53 induced by sunitinib, however, does not require p53 nuclear export signals. Indeed, p53 degradation is achieved by the nucleus-to-cytoplasm transport of its nuclear binding target HMGB1, shifting the distribution of p53 from the nucleus to the cytoplasm. Then cytoplasmic p53 directly interacts with the autophagy cargo receptor p62 to promote degradation. Importantly, inhibition of HMGB1 sensitizes cancer cell to sunitinib. Taken together, our study identified an alternative p53 protein turnover mechanism induced by sunitinib, thus not only elucidating the underlying mechanisms that limit sunitinib efficacy in cancer therapy but also opening an avenue for expanding the clinical indications of sunitinib. Note: This abstract was not presented at the meeting. Citation Format: Qiaojun He, Peihua Luo, Xiaochun Yang, Qinjie Weng, Ling Ding, Bo Yang. HMGB1 governs p53 to autophagic degradation via its nucleus-to-cytoplasm transport [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2070. doi:10.1158/1538-7445.AM2017-2070

P2.06-002 Phase I Study of DS-6051b, a ROS1/NTRK Inhibitor, in Japanese Subjects with Advanced Solid Tumors Harboring Either a ROS1 or NTRK Fusion Gene: Topic: Phase I Trials

Oncogenic gene fusions of ROS1 or NTRK have been reported in various cancers. DS-6051b is an orally available small molecule receptor tyrosine kinase inhibitor with high affinity for the ROS1 and NTRK receptors. Non-clinical pharmacology studies demonstrated anticancer activity of DS-6051b against several types of human tumor harboring ROS1 or NTRK fusion gene in cultured cells and xenograft models. This is an ongoing phase 1 study in Japanese subjects with advanced solid tumors harboring either a ROS1 or NTRK fusion gene. Subjects receive doses of DS-6051b from 400mg to 800mg once daily (QD). Pharmacokinetics (PK) samples are collected from Day1 to Day22. Primary objective is to assess the safety profile and secondary objectives are to determine the maximum tolerated dose (MTD), the recommended phase 2 dose (RP2D), and to assess the PK profile. The efficacy of DS-6051b is an exploratory assessment performed by investigator judgment per RECIST v.1.1. As of June 27, 2016, a total of 9 subjects were enrolled. Median age was 51 (43-69) years, 56% were female, all 9 subjects were ROS1 fusion positive non-small cell lung cancer patients, and 3 subjects had prior crizotinib treatment. Subjects received DS-6051b at doses of 400mg QD (n=6) and 800mg QD (n=3). There were no DLTs in the 400mg QD cohort, and 2 out of 3 subjects in the 800mg QD cohort experienced DLT with grade 3 AST/ALT increased. To evaluate the MTD and RP2D more in detail, 600mg QD cohort is planned. Common adverse events were AST increased, ALT increased, diarrhea, and constipation. Among 7 patients who had target lesion, 4 subjects showed partial response, 3 subjects showed stable disease. PK data indicated the plasma drug concentration increases as the dose increases. This study is categorized as “Clinical Trial in Progress.” This study was initiated from February 2016 and estimated primary completion date will be September 2018.

Abstract CT024: First-in-human phase 1 dose-escalation study of DS-6051b, an oral ROS1 and NTRK inhibitor, in subjects with advanced solid tumors

Abstract Background: DS-6051b is an orally available small molecule receptor tyrosine kinase inhibitor with high affinity for the ROS1 and NTRK receptors. Non-clinical pharmacology studies demonstrated activity of DS-6051b against tumors harboring ROS1 or NTRK fusion genes in cell culture and xenograft models. The objectives of this first in human (FIH) study are to assess safety and tolerability of DS-6051b in cancer subjects and identify the maximum tolerated dose (MTD) and the tentative RP2D. Pharmacokinetics (PK), QT prolongation, and tumor responses are also assessed in this study (Clinical Trial Information: NCT02279433). Methods: Dose escalation initially followed an accelerated titration design enrolling a single subject at each dose level, and then adopted the modified continuous reassessment method using a Bayesian logistic regression model and escalation with overdose control. Adult subjects with advanced solid tumors harboring ROS1 or NTRK1-3 fusion genes; or with neuroendocrine carcinoma; or with advanced solid tumors with tumor-induced pain are eligible for the study. DS-6051b is orally administered once-daily in 21-day cycles. Tumor assessments are performed every 3 cycles using RECIST 1.1 criteria. Plasma PK samples and time-matched ECG data are collected at multiple time points. Results: A total of 22 subjects have been enrolled at 50, 100, 200, 400, 800, and 1200 mg once daily (QD) dose levels. Enrolled population included 11 subjects with neuroendocrine carcinomas, 9 subjects with advanced solid tumors with tumor-induced pain, 1 subject with ROS1 fusion-positive NSCLC liver metastases, and 1 subject with leiomyosarcoma with a ROS1 point mutation. Two dose-limiting toxicities occurred in subjects who received 1200 mg QD, consisting of grade 3 transaminase elevations. The MTD is 800 mg QD. The most frequent (?20%) TEAEs were diarrhea, nausea, vomiting, dehydration, dizziness, dysgeusia, and fatigue, which were predominantly grade ?2. Cmax and AUC increased with the dose. Plasma terminal half-life was 11-24 hours. Steady state AUC was approximately 3 to 4-fold higher than that of Cycle 1 Day 1. Two subjects showed partial response: One with neuroendocrine carcinoma, who received 800 mg QD (33% decrease in tumor size), and one with ROS1 fusion-positive NSCLC liver metastases, who received 1200 mg QD (44% decrease in tumor size). Notably, the latter subject had progressed on crizotinib (best objective response stable disease) and ceritinib (progressive disease). Conclusions: DS-6051b has been well tolerated up to 800 mg QD in subjects with advanced solid tumors. The observed efficacy signals in two subjects with partial response warrant further evaluation. This trial is now selectively accruing subjects with ROS1 fusion-positive tumors. Citation Format: Kyriakos P. Papadopoulos, Erkut Borazanci, Daniel Von Hoff, Leena Gandhi, Amita Patnaik, Masaya Tachibana, Hamim Zahir, Roohi Gajee, Terri Goldberg, Giorgio Senaldi, Sai-Hong Ou. First-in-human phase 1 dose-escalation study of DS-6051b, an oral ROS1 and NTRK inhibitor, in subjects with advanced solid tumors. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr CT024.

"Vertical" Inhibition of HER2 Yields Horizontal Gains in the Clinic.

HER2-targeted therapy has moved beyond trastuzumab to include other monoclonals targeting the cell surface, receptor tyrosine kinase inhibitors of HER2, and antibody-drug conjugates. Afatinib, a small molecule receptor tyrosine kinase inhibitor, now joins the ranks of HER2-targeting agents in combination with trastuzumab. The combination brings new opportunities and challenges.

Abstract A23: ALK activity in macrophages drives metastasis in murine models of breast cancer

Abstract VEGF-induced angiogenesis and macrophages contribute directly to metastasis, the leading cause of breast cancer related mortality. VEGF is a major driver of angiogenesis, yet its targeted inhibition is often ineffective at controlling metastases. In contrast, pathways that contribute to a pro-metastatic macrophage phenotype are unclear and pharmacological strategies to inhibit pro-metastatic activity are lacking. In this study, we illustrate that anti-VEGF therapy modulates PTN expression in multiple mouse models of breast cancer. Once expressed, PTN induces the expression of VEGFR2 on macrophages and promotes an anti-inflammatory, pro-metastatic macrophage phenotype. This phenomenon is dependent on ALK signaling, as inhibition with the small molecule receptor tyrosine kinase inhibitor crizotinib (Xalkori, Pfizer), which targets ALK, or ALK siRNA is sufficient to reverse PTN-induced VEGFR2 and anti-inflammatory macrophage marker expression. Importantly, phosphorylated ALK and VEGFR2 positive macrophages were detected in tumor but not normal breast tissue from patients. Furthermore, inhibition of ALK signaling in macrophages blunted metastasis but had no effect on primary MMTV-PyMT tumors; while blockade of VEGF slowed primary tumor growth without effect on metastatic burden. Combined inhibition of ALK and VEGF activity showed potent anti-tumor and anti-metastatic activity in animals with disseminated disease. Collectively, our data document novel markers of pro-metastatic macrophages and reveal how macrophage phenotype can be manipulated to suppress breast cancer progression. Citation Format: Kristi D. Lynn, Rolf A. Brekken. ALK activity in macrophages drives metastasis in murine models of breast cancer. [abstract]. In: Abstracts: AACR Special Conference on Cellular Heterogeneity in the Tumor Microenvironment; 2014 Feb 26-Mar 1; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(1 Suppl):Abstract nr A23. doi:10.1158/1538-7445.CHTME14-A23

Axitinib Improves Radiotherapy in Murine Xenograft Lung Tumors

A third of patients with non-small cell lung cancer (NSCLC) present with un-resectable stage III locally advanced disease and are currently treated by chemo-radiotherapy but the median survival is only about 21months. Using an orthotopic xenograft model of lung carcinoma, we have investigated the combination of radiotherapy with the anti-angiogenic drug axitinib (AG-013736, Pfizer), which is a small molecule receptor tyrosine kinase inhibitor that selectively targets the signal transduction induced by VEGF binding to VEGFR receptors. We have tested the combination of axitinib with radiotherapy in nude mice bearing human NSCLC A549 lung tumors. The therapy effect was quantitatively evaluated in lung tumor nodules. The modulation of radiation-induced pneumonitis, vascular damage and fibrosis by axitinib was assessed in lung tissue. Lung irradiation combined with long-term axitinib treatment was safe resulting in minimal weight loss and no vascular injury in heart, liver and kidney tissues. A significant decrease in the size of lung tumor nodules was observed with either axitinib or radiation, associated with a decrease in Ki-67 staining and a heavy infiltration of inflammatory cells in tumor nodules. The lungs of mice treated with radiation and axitinib showed a complete response with no detectable residual tumor nodules. A decrease in pneumonitis, vascular damage and fibrosis were observed in lung tissues from mice treated with radiation and axitinib. Our studies suggest that axitinib is a potent and safe drug to use in conjunction with radiotherapy for lung cancer that could also act as a radioprotector for lung tissue by reducing pneumonitis and fibrosis.

Abstract 1618: Combination of axitinib and crizotinib in renal cell carcinoma models.

Abstract Background: The vascular endothelium growth factor (VEGF) pathway plays a pivotal role in angiogenesis. Axitinib (AG-013736), a potent small molecule receptor tyrosine kinase inhibitor highly selective for VEGF receptor 1, 2 and 3, is currently being tested in Phase II/III clinical trials for the treatment of solid tumors and has been approved as a second-line treatment for renal cell carcinoma (RCC). The hepatocyte growth factor (HGF)/mesenchymal-epithelial transition factor (c-Met) pathway has also been shown to play an important role in tumor vascularization, as well as epithelial to mesenchymal transition (EMT), metastatization, and acquired resistance. Crizotinib (PF-02341066), a potent and selective inhibitor of anaplastic lymphoma kinase (ALK) and c-Met kinase, has been approved for the treatment of advanced ALK-positive non-small cell lung cancer. The aim of this study was to assess the combinational effect of axitinib and crizotinib in two models of RCC with differing degrees of c-Met expression and sensitivity to anti-angiogenic agents. We hypothesized that the combination would provide greater anti-tumor and anti-angiogenesis efficacy compared to single-agents. Methods: Human high c-Met expressing 786-O and low c-Met expressing RP-01 (developed from a skin metastasis of a patient with sporadic clear cell RCC) xenografts were inoculated into SCID mice (8/group). After approximately 6 weeks of tumor growth, mice were treated with vehicle, axitinib (36 mg/kg, 2x/day, oral gavage), crizotinib (25 mg/kg, 1x/day, oral gavage), or axitinib plus crizotinib. Once tumor volume of vehicle mice reached 200 mm2, mice were sacrificed and tumor tissue was excised and analyzed. A sunitinib-resistant RP-01 model was also developed through continued in vivo exposure to sunitinib (60 mg/kg, 1x/day, oral gavage) to further test the different responses to treatments and to evaluate the possible role of c-Met in sunitinib resistance. Compounds were kindly provided by Pfizer. Results: We observed that single-agent crizotinib anti-tumoral activity was strongly related to c-Met expression, inhibiting 786-O tumor growth in vivo, but not RP-01. More interestingly, significant synergistic effects were found with crizotinib and axitinib, whereby enhanced inhibition of 786-O xenograft tumor growth was found (from 17%, axitinib, to 76% combination, p &amp;lt;0.05 of combination vs. both single agents). No overt signs of toxicity were observed in any of the experimental groups. Vessel density, pericyte coverage (CD31 and NG2), and EMT markers are being evaluated with immunohistochemistry. Results from combination treatment in the sunitinib-resistant model will be presented. Summary: Overall, the data demonstrate that this combination therapy resulted in significant anti-tumor activity in a high c-Met expressing RCC model, highlighting the potential therapeutic application of combined VEGF and c-Met blockade in the treatment of RCC. Citation Format: Eric S. Ciamporcero, Kiersten M. Miles, Remi Adelaiye, Stefania Pizzimenti, Giuseppina Barrera, Roberto Pili. Combination of axitinib and crizotinib in renal cell carcinoma models. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1618. doi:10.1158/1538-7445.AM2013-1618

Abstract 4710: Sunitinib prevents tumor-induced immunotolerance in novel murine model of hepatocellular carcinoma (HCC) through modulating CD4+CD25+Foxp3+ regulatory T cells via TGF-β signaling.

Abstract The high rate of mortality, frequent incidence of recurrence, and limited benefit of current therapies for hepatocellular carcinoma underline the urgent need for new therapeutic approaches. Immunotherapy has been demonstrated to be a promising strategy for this lethal disease. However, tumor progression induced immunotolerance abrogates effective immune responses and prevents the development of successful immunotherapeutic strategies. In this study, we evaluated the role of sunitinib, a FDA approved chemotherapeutic agent, in preventing tumor-induced immunotolerance and investigated the underlying cellular and molecular mechanisms. Recently, we've established a novel fibrotic and orthotopic murine model of HCC through seeding of tumorigenic hepatocytes from SV40 T antigen (Tag) transgenic MTD2 mice into the livers of syngeneic C57BL/6 mice followed by carbon tetrachloride treatment. This model mimics human HCC progression and recapitulates typical histologic, biologic, and immunologic features of this disease. Using this model, we've demonstrated that the treatment of sunitinib, a small molecule receptor tyrosine kinase inhibitor (RTKI), restrains the tumor growth in advanced HCC. Interestingly, sunitinib treatment also induces the proliferation and differentiation of tumor antigen-specific CD8 T cells in tumor bearing mice, evidenced by significantly higher portion of CD8 T cells that produced IFN-γ and TNF-α in response to tumor antigen stimulation. Subsequent findings revealed that sunitinib treatment led to the reduction in the frequency of CD4+CD25+Foxp3+ Treg and decrease in TGF-β expression. In vitro experiments indicated that Tregs in tumor-bearing mice express higher level of TGF-β and strongly suppress the function of CD4 and CD8 T cells in a dose-dependent manner compared to that in tumor-free mice. Tregs in tumor-bearing mice treated with sunitinib exhibited reduced suppressive function compared to that in tumor-bearing mice treated with vehicle. Further, the suppressive function of Tregs from tumor-bearing mice can be partly inhibited by blocking TGF-β with anti-TGF-β antibody. In addition, we've demonstrated that tumor lysate drives CD4+CD25- naïve T cells differentiation into CD4+CD25+Foxp3+ Tregs and this differentiation could be partially neutralized with anti-TGF-β antibody. In conclusion, our findings indicated that sunitinib treatment prevents tumor-induced immunotolerance through reducing the frequency and suppressive function of Tregs via TGF-β signaling pathway. Citation Format: Dai Liu, Guangfu Li, Eric T. Kimchi, Qing X. Yang, Todd Schell, Kevin F. Staveley-O'Carroll. Sunitinib prevents tumor-induced immunotolerance in novel murine model of hepatocellular carcinoma (HCC) through modulating CD4+CD25+Foxp3+ regulatory T cells via TGF-β signaling. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4710. doi:10.1158/1538-7445.AM2013-4710

Enhanced Therapeutic Efficacy By Radiation Therapy Combined With Axitinib in a Preclinical Model of Lung Carcinoma

A third of patients with non-small cell lung cancer (NSCLC) present with unresectable stage III locally advanced disease and are currently treated by chemo-radiation therapy. The median survival is only about 21 months, emphasizing the need to improve the therapeutic outcomes. We have investigated the combination of radiation therapy with axitinib (AG-013736, Pfizer). Axitinib, an anti-angiogenic drug, is a small molecule receptor tyrosine kinase inhibitor, which selectively targets the signal transduction induced by VEGF binding to VEGFR receptors.

Fatal Liver Failure in a Patient Treated With Sunitinib for Renal Cell Carcinoma

Introduction Sunitinib (sunitinib malate, SU11248, SUTENT; Pfizer, New York, NY) is a novel small molecule receptor tyrosine kinase inhibitor with direct antitumor as well as antiangiogenic activity via targeting the vascular endothelial growth factor, platelet-derived growth factor, KIT, and FLT3 receptor tyrosine kinases. The drug is approved multinationally for the treatment of renal cell carcinoma (RCC), gastrointestinal stromal tumor, and pancreatic neuroendocrine tumor. The safety of sunitinib has been studied in patients with RCC with only a relatively small proportion of patients with grade 2/3 liver toxicity and no grade 4 toxicity. A few case reports described serious liver toxicity, including fatal outcome ascribed to the treatment with sunitinib. Here we report a case of a patient ith RCC and chronic obstructive lung disease accompanied by evere pulmonary arterial hypertension that developed fulminant heatic failure during the first cycle of treatment with sunitinib. A ossible mechanism of toxicity in this case and review of the literature re presented in this report.

Development of a rat model of oral small molecule receptor tyrosine kinase inhibitor-induced diarrhea

Orally administered small molecule receptor tyrosine kinase inhibitors (RTKIs) are increasingly common treatments for cancer, both alone and in combination with chemotherapy. However, their side effect profiles and the underlying mechanisms of such are not yet fully elucidated. Management of their most common dose limiting side effect, diarrhea, has been hampered by a lack of suitable animal models. We aimed to develop a clinically relevant rat model of RTKI-induced diarrhea that could be utilized for investigating supportive care interventions and pharmacokinetics. Albino Wistar rats were treated daily for 4 weeks with various concentrations of lapatinib to determine the optimal dose for development of diarrhea. This was then followed by an experiment with addition of paclitaxel once weekly for 4 weeks to observe effects of combination drug treatment on diarrhea. Data regarding animal tolerance to the treatment, organ weights, circulating lapatinib concentration and histopathology were collected weekly. Lapatinib caused diarrhea in rats that was dose-dependent. Diarrhea occurred without causing significant intestinal histopathology. Follow up experiments are currently underway to determine the exact pathogenesis and mechanisms of lapatinib-induced diarrhea and potential protective strategies.