Cabozantinib for the treatment of renal cell carcinoma

FDA-approved small molecule kinase inhibitors for cancer treatment (2001-2015): Medical indication, structural optimization, and binding mode Part I

The dysregulation of kinases has emerged as a major class of targets for anticancer drug discovery given its node roles in the etiology of tumorigenesis, progression, invasion, and metastasis of malignancies, which is validated by the FDA approval of 28 small molecule kinase inhibitor (SMKI) drugs for cancer treatment at the end of 2015. While the preclinical and clinical data of these drugs are widely presented, it is highly essential to give an updated review on the medical indications, design principles and binding modes of these anti-tumor SMKIs approved by the FDA to offer insights for the future development of SMKIs with specific efficacy and safety.

Machine learning models to predict ligand binding affinity for the orexin 1 receptor

The orexin 1 receptor (OX1R) is a G-protein coupled receptor that regulates a variety of physiological processes through interactions with the neuropeptides orexin A and B. Selective OX1R antagonists exhibit therapeutic effects in preclinical models of several behavioral disorders, including drug seeking and overeating. However, currently there are no selective OX1R antagonists approved for clinical use, fueling demand for novel compounds that act at this target. In this study, we meticulously curated a dataset comprising over 1300 OX1R ligands using a stringent filter and criteria cascade. Subsequently, we developed highly predictive quantitative structure-activity relationship (QSAR) models employing the optimized hyper-parameters for the random forest machine learning algorithm and twelve 2D molecular descriptors selected by recursive feature elimination with a 5-fold cross-validation process. The predictive capacity of the QSAR model was further assessed using an external test set and enrichment study, confirming its high predictivity. The practical applicability of our final QSAR model was demonstrated through virtual screening of the DrugBank database. This revealed two FDA-approved drugs (isavuconazole and cabozantinib) as potential OX1R ligands, confirmed by radiolabeled OX1R binding assays. To our best knowledge, this study represents the first report of highly predictive QSAR models on a large comprehensive dataset of diverse OX1R ligands, which should prove useful for the discovery and design of new compounds targeting this receptor.

Cabozantinib-nivolumab sequence in metastatic renal cell carcinoma: the CABIR study

Nivolumab and cabozantinib are approved agents in mRCC patients after sunitinib/pazopanib (TKI) failure. However, the optimal sequence, cabozantinib then nivolumab (CN) or nivolumab then cabozantinib (NC), is still unknown. The CABIR study aimed to identify the optimal sequence between CN and NC after frontline VEGFR‐TKI. In this multicenter retrospective study, we collected data from mRCC pts receiving CN or NC, after frontline VEGFR‐TKI. A propensity score (PrS) was calculated to manage bias selection, and sequence comparisons were carried out with a cox model on a matched sample 1:1. The primary endpoint was progression‐free survival (PFS) from the start of second line to progression in third line (PFS_2‐3). Key secondary endpoints included overall survival from second line (OS₂). Out of 139 included mRCC patients, 38 (27%) and 101 (73%) received CN and NC, respectively. Overlap in PrS allowed 1:1 matching for each CN pts, with characteristics well balanced. For both PFS_2‐3 and OS₂, NC sequence was superior to CN (PFS_2‐3: HR = 0.58 [0.34‐0.98], P = .043; OS₂: 0.66 [0.42‐1.05], P = .080). Superior PFS_2‐3 was in patients treated between 6 and 18 months with prior VEGFR‐TKI (P = .019) and was driven by a higher PFS_L3 with cabozantinib when given after nivolumab (P < .001). The CABIR study shows a prolonged PFS of the NC sequence compared to CN in mRCC after first line VEGFR‐TKI failure. The data suggest that cabozantinib may be more effective than nivolumab in the third‐line setting, possibly related to an ability of cabozantinib to overcome resistance to PD‐1 blockade.

cMET - a prognostic marker in papillary renal cell carcinoma?

BACKGROUND

The tyrosine-protein kinase c-Met plays a decisive role in numerous cellular processes, as a proto-oncogene that supports aggressive tumor behavior. It is still unknown whether c-Met could be relevant for prognosis of papillary RCC (pRCC).

PATIENTS AND METHODS

Specimen collection were a collaboration of the PANZAR consortium. Patients' medical history and tumor specimens were collected from n=197 and n=110 patients with type 1 and 2 pRCC, respectively. Expression of cMET was determined by immunohistochemistry (IHC).

RESULTS

In total, cMET staining was evaluable in of 97/197 type 1 and 63/110 type 2 of pRCC cases. Five-years overall survival reviled no significant difference in dependence of cMET positivity (cMET^- vs. cMET⁺: pRCC type 1: 84.8 % vs. 80.3 %, respectively (p=0.303, log-rank); type 2: 71.4 % vs. 64.4 % respectively (p= 0.239, log-rank)). Interestingly, the subgroup analyses showed a significant difference for cMET expression in T stage and metastases of the pRCC type 2 (p=0.014, p=0.022, chi-square). The cMET positive type 2 collective developed more metastases compared to the cMET negative cohort (pRCC Typ 2 M+: cMET^-: 2 (4.3%) vs. cMET⁺: 12 (19%)).

CONCLUSION

CMET expression did not qualify as a prognostic marker in pRCC for overall survival.

Cabozantinib plus immunotherapy combinations in metastatic renal cell and urothelial carcinoma

Treatment options for metastatic renal cell carcinoma (mRCC) and metastatic urothelial carcinoma (mUC) have increased dramatically over the past decade. However, even when novel approaches have proven to be effective as monotherapy, many patients still develop progressive disease, and different strategies are needed to increase clinical response and quality of life. Strategies combining targeted therapy (TT) and immunotherapy (IO) have emerged as a way to shorten the gap between responders and nonresponders to monotherapy and have reported promising results. In this review, we discuss the current role of cabozantinib in combination with IO agents in the treatment of metastatic RCC and UC and go over future directions in the field.

Small Molecule Kinase Inhibitor Drugs (1995-2021): Medical Indication, Pharmacology, and Synthesis

The central role of dysregulated kinase activity in the etiology of progressive disorders, including cancer, has fostered incremental efforts on drug discovery programs over the past 40 years. As a result, kinase inhibitors are today one of the most important classes of drugs. The FDA approved 73 small molecule kinase inhibitor drugs until September 2021, and additional inhibitors were approved by other regulatory agencies during that time. To complement the published literature on clinical kinase inhibitors, we have prepared a review that recaps this large data set into an accessible format for the medicinal chemistry community. Along with the therapeutic and pharmacological properties of each kinase inhibitor approved across the world until 2020, we provide the synthesis routes originally used during the discovery phase, many of which were only available in patent applications. In the last section, we also provide an update on kinase inhibitor drugs approved in 2021.

Cabozantinib and nivolumab as first-line treatment in advanced renal cell carcinoma

INTRODUCTION

In the last decade, there have been substantial changes in the management of metastatic renal cell carcinoma (mRCC) with combined regimens with immune checkpoint inhibitors (ICI) replacing targeted therapies. These combined regimens include the combination of cabozantinib plus nivolumab.

AREAS COVERED

Here, we provide an overview of clinical trials evaluating the combination of cabozantinib and nivolumab and the current clinical data on mechanism of action, pharmacokinetics, efficacy, and safety profile.

EXPERT OPINION

Dual immune checkpoint inhibition with nivolumab and ipilimumab as well as the combination of a vascular endothelial growth factor (VEGF) inhibitor and an immune checkpoint inhibitor have shown to improve outcomes in phase III trials in comparison to sunitinib (axitinib plus pembrolizumab, axitinib plus avelumab, bevacizumab plus atezolizumab, cabozantinib plus nivolumab, lenvatinib plus pembrolizumab). However, to date, there are no head-to-head trials comparing these new combination therapies and no biomarkers are available to guide the optimal choice of first line therapy.

An up-to-date evaluation of cabozantinib for the treatment of renal cell carcinoma

Introduction: In the evolving treatment scenario of metastatic renal cell carcinoma, cabozantinib is gaining increasing attention, presenting as a cornerstone therapy, both as a monotherapy and in combination with immune-checkpoint inhibitors.Areas covered: In this review, the authors explore the role of cabozantinib in the treatment of metastatic clear cell and non-clear cell renal cell carcinoma, presenting data from the most recent clinical trials and investigating ongoing studies. They, furthermore, evaluate the pharmacokinetic, pharmacodynamic, and immunomodulatory effect of cabozantinib, as well as underlining the tolerability profile and patients' quality of life.Expert opinion: Cabozantinib's administration as a single agent is restricted to intermediate- and poor-risk patients (according to IMDC criteria). The further advent of anti-VEGF-receptor tyrosine kinase inhibitors combined with immune checkpoint inhibitor regimens (such as pembrolizumab + axitinib) has allowed to expand the use of cabozantinib, leading to its combination with nivolumab. In the next few years, more information is required to look for the application of cabozantinib-based combinations as a later-line approach in metastatic RCC patients, beside their use in the first-line setting.

Clear-cell renal cell carcinoma - A comprehensive review of agents used in the contemporary management of advanced/metastatic disease

Renal cell carcinoma represents the most common malignancy of the kidney and the majority of cases are categorized as clear cell carcinomas. The elucidation of the specific alterations in key molecular and metabolic pathways responsible for cancer development and progression have prompted the rationalization of our classification of this disease and have provided specific targetable molecules implicated in carcinogenesis. Although immunotherapy has been an established option in the treatment of metastatic renal cell cancer for many years, its role has been renewed and upgraded with the implementation of anti-angiogenic agents and immune checkpoint inhibitors in our treatment armamentarium. The future holds promise, as newer agents become available and combination regimens of immunotherapy with anti-angiogenic agents have become the standard of care in the management of metastatic disease and are currently being evaluated in earlier settings. Proper patient selection and individualization of our treatment strategies are of utmost importance in order to provide optimal care to patients suffering from renal cell carcinoma.

Structural Basis for Vascular Endothelial Growth Factor Receptor Activation and Implications for Disease Therapy

Vascular endothelial growth factors (VEGFs) bind to membrane receptors on a wide variety of cells to regulate diverse biological responses. The VEGF-A family member promotes vasculogenesis and angiogenesis, processes which are essential for vascular development and physiology. As angiogenesis can be subverted in many disease states, including tumour development and progression, there is much interest in understanding the mechanistic basis for how VEGF-A regulates cell and tissue function. VEGF-A binds with high affinity to two VEGF receptor tyrosine kinases (VEGFR1, VEGFR2) and with lower affinity to co-receptors called neuropilin-1 and neuropilin-2 (NRP1, NRP2). Here, we use a structural viewpoint to summarise our current knowledge of VEGF-VEGFR activation and signal transduction. As targeting VEGF-VEGFR activation holds much therapeutic promise, we examine the structural basis for anti-angiogenic therapy using small-molecule compounds such as tyrosine kinase inhibitors that block VEGFR activation and downstream signalling. This review provides a rational basis towards reconciling VEGF and VEGFR structure and function in developing new therapeutics for a diverse range of ailments.

Tracing Clonal Dynamics Reveals that Two- and Three-dimensional Patient-derived Cell Models Capture Tumor Heterogeneity of Clear Cell Renal Cell Carcinoma

BACKGROUND

Extensive DNA sequencing has led to an unprecedented view of the diversity of individual genomes and their evolution among patients with clear cell renal cell carcinoma (ccRCC).

OBJECTIVE

To understand subclonal architecture and dynamics of patient-derived two-dimensional (2D) and three-dimensional (3D) ccRCC models in vitro, in order to determine whether they mirror ccRCC inter- and intratumor heterogeneity.

DESIGN, SETTING, AND PARTICIPANTS

We have established a comprehensive platform of living renal cancer cell models from ccRCC surgical specimens.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

We confirmed the concordance of 2D and 3D patient-derived cell (PDC) models with the original tumor tissue in terms of histology, biomarker expression, cancer driver mutations, and copy number alterations. We addressed inter- and intrapatient heterogeneity by analyzing clonal dynamics during serial passaging.

RESULTS AND LIMITATIONS

In-depth genetic characterization verified the presence of heterogeneous cell populations, and revealed a high degree of similarity between subclonal compositions of monolayer and organoid cell cultures and the corresponding parental ccRCCs. Clonal dynamics were evident during serial passaging of cells in vitro, suggesting that PDC cultures can offer insights into evolutionary potential and treatment susceptibility of ccRCC subclones in vivo. Proof-of-concept drug profiling using selected ccRCC-targeted therapy agents highlighted patient-specific vulnerabilities in PDC models that could not be anticipated by interrogating commercially available cell lines.

CONCLUSIONS

We demonstrate that PDC models mirror inter- and intratumor heterogeneity of ccRCC in vitro. Based on our findings, we envision that the use of these models will advance our understanding of the trajectories that cause genetic diversity and their consequences for treatment on an individual level.

PATIENT SUMMARY

In this study, we developed two- and three-dimensional patient-derived models from clear cell renal cell carcinoma (ccRCC) as "mini-tumors in a dish." We show that these cell models retain important features of the human ccRCCs such as the profound tumor heterogeneity, thus highlighting their importance for cancer research and precision medicine.

Cabozantinib for the Management of Metastatic Clear Cell Renal Cell Carcinoma

Cabozantinib is a multi-tyrosine kinase inhibitor used for the treatment of various solid-organ tumours. It was recently approved as a first- and second-line therapeutic for the management of advanced/metastatic renal cell carcinoma based on the results of two randomised controlled trials. The phase III METEOR trial compared cabozantinib against everolimus as a second- or greater line therapy and found benefits in progression-free and overall survival, and the phase II CABOSUN trial compared cabozantinib against sunitinib as a first-line therapeutic and found benefits in terms of progression-free survival. This review briefly summarises how cabozantinib fits into current treatment paradigms for the management of advanced renal cell carcinoma.

Crosstalk between VEGFR and other receptor tyrosine kinases for TKI therapy of metastatic renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is the most common subtype of renal cell carcinoma (RCC), and is frequently accompanied by the genetic features of von Hippel–Lindau (VHL) loss. VHL loss increases the expression of hypoxia-inducible factors (HIFs) and their targets, including epidermal growth factor (EGF), vascular endothelial growth factor (VEGF), and platelet-derived growth factor (PDGF). The primary treatment for metastatic RCC (mRCC) is molecular-targeted therapy, especially anti-angiogenic therapy. VEGF monoclonal antibodies and VEGF receptor (VEGFR) tyrosine kinase inhibitors (TKIs) are the main drugs used in anti-angiogenic therapy. However, crosstalk between VEGFR and other tyrosine kinase or downstream pathways produce resistance to TKI treatment, and the multi-target inhibitors, HIF inhibitors or combination strategies are promising strategies for mRCC. HIFs are upstream of the crosstalk between the growth factors, and these factors may regulate the expression of VEGR, EGF, PDGF and other growth factors. The frequent VHL loss in ccRCC increases HIF expression, and HIFs may be an ideal candidate to overcome the TKI resistance. The combination of HIF inhibitors and immune checkpoint inhibitors is also anticipated. Various clinical trials of programmed cell death protein 1 inhibitors are planned. The present study reviews the effects of current and potential TKIs on mRCC, with a focus on VEGF/VEGFR and other targets for mRCC therapy.

Function of the c-Met receptor tyrosine kinase in carcinogenesis and associated therapeutic opportunities

c-Met is a receptor tyrosine kinase belonging to the MET (MNNG HOS transforming gene) family, and is expressed on the surfaces of various cells. Hepatocyte growth factor (HGF) is the ligand for this receptor. The binding of HGF to c-Met initiates a series of intracellular signals that mediate embryogenesis and wound healing in normal cells. However, in cancer cells, aberrant HGF/c-Met axis activation, which is closely related to c-Met gene mutations, overexpression, and amplification, promotes tumor development and progression by stimulating the PI3K/AKT, Ras/MAPK, JAK/STAT, SRC, Wnt/β-catenin, and other signaling pathways. Thus, c-Met and its associated signaling pathways are clinically important therapeutic targets. In this review, we elaborate on the molecular structure of c-Met and HGF and the mechanism through which their interaction activates the PI3K/AKT, Ras/MAPK, and Wnt signaling pathways. We also summarize the connection between c-Met and RON and EGFR, which are also receptor tyrosine kinases. Finally, we introduce the current therapeutic drugs that target c-Met in primary tumors, and their use in clinical research.