Multicenter, phase II study of axitinib, a selective second-generation inhibitor of vascular endothelial growth factor receptors 1, 2, and 3, in patients with metastatic melanoma

VEGF/VEGFR axis and its signaling in melanoma: Current knowledge toward therapeutic targeting agents and future perspectives

Melanoma is responsible for most skin cancer-associated deaths globally. The progression of melanoma is influenced by a number of pathogenic processes. Understanding the VEGF/VEGFR axis, which includes VEGF-A, PlGF, VEGF-B, VEGF-C, and VEGF-D and their receptors, VEGFR-1, VEGFR-2, and VEGFR-3, is of great importance in melanoma due to its crucial role in angiogenesis. This axis generates multifactorial and complex cellular signaling, engaging the MAPK/ERK, PI3K/AKT, PKC, PLC-γ, and FAK signaling pathways. Melanoma cell growth and proliferation, migration and metastasis, survival, and acquired resistance to therapy are influenced by this axis. The VEGF/VEGFR axis was extensively examined for their potential as diagnostic/prognostic biomarkers in melanoma patients and results showed that VEGF overexpression can be associated with unfavorable prognosis, higher level of tumor invasion and poor response to therapy. MicroRNAs linking to the VEGF/VEGFR axis were identified and, in this review, divided into two categories according to their functions, some of them promote melanoma angiogenesis (promotive group) and some restrict melanoma angiogenesis (protective group). In addition, the approach of treating melanoma by targeting the VEGF/VEGFR axis has garnered significant interest among researchers. These agents can be divided into two main groups: anti-VEGF and VEGFR inhibitors. These therapeutic options may be a prominent step along with the modern targeting and immune therapies for better coverage of pathological processes leading to melanoma progression and therapy resistance.

Recent advances in tyrosine kinase inhibitors VEGFR 1-3 for the treatment of advanced metastatic melanoma

INTRODUCTION

Increasing evidence from preclinical and clinical studies suggests the role of vascular endothelial growth factor (VEGF) signaling in melanoma progression, response to therapy, and overall survival. Moreover, the discovery of the potential involvement of the VEGF pathway in resistance to immunotherapy has led to new clinical trials with VEGFR inhibitors.

AREAS COVERED

We have reviewed recent literature, mainly published within the last 5 years, on VEGFR-targeted treatments for advanced melanoma, including mucosal, acral, and uveal melanoma. The VEGFR inhibitors were used as a single therapy or combined with either immunotherapy or chemotherapy, and they were employed in treatment for KIT-mutated cutaneous melanoma and for patients with brain metastases.

EXPERT OPINION

Trials involving monotherapy have been unsuccessful in demonstrating meaningful efficacy. Despite some activity, the combination of VEGFR-targeting tyrosine kinase inhibitors (TKIs) with immune checkpoint inhibitors (ICI) in patients with ICI-resistant melanoma, the combination did not significantly improve outcomes compared to anti-PD-1 monotherapy in the first-line settings. On the contrary, some patients with mucosal, acral or KIT-mutant melanoma may benefit from TKI-based therapies. Further studies focused on biomarker discovery and randomized trials are necessary to better understand the role of VEGFR1-3 as a therapeutic target in melanoma.

Advances in targeted therapy and immunotherapy for melanoma (Review)

Melanoma is the most aggressive and deadly type of skin cancer and is known for its poor prognosis as soon as metastasis occurs. Since 2011, new and effective therapies for metastatic melanoma have emerged, with US Food and Drug Administration approval of multiple targeted agents, such as V-Raf murine sarcoma viral oncogene homolog B1/mitogen-activated protein kinase kinase inhibitors and multiple immunotherapy agents, such as cytotoxic T lymphocyte-associated protein 4 and anti-programmed cell death protein 1/ligand 1 blockade. Based on insight into the respective advantages of the above two strategies, the present article provided a review of clinical trials of the application of targeted therapy and immunotherapy, as well as novel approaches of their combinations for the treatment of metastatic melanoma in recent years, with a focus on upcoming initiatives to improve the efficacy of these treatment approaches for metastatic melanoma.

Neoadjuvant treatment for stage III and IV cutaneous melanoma

BACKGROUND

Cutaneous melanoma is amongst the most aggressive of all skin cancers. Neoadjuvant treatment is a form of induction therapy, given to shrink a cancerous tumour prior to the main treatment (usually surgery). The purpose is to improve survival and surgical outcomes. This review systematically appraises the literature investigating the use of neoadjuvant treatment for stage III and IV cutaneous melanoma.

OBJECTIVES

To assess the effects of neoadjuvant treatment in adults with stage III or stage IV melanoma according to the seventh edition American Joint Committee on Cancer (AJCC) staging system.

SEARCH METHODS

We searched the following databases up to 10 August 2021 inclusive: Cochrane Skin Specialised Register, CENTRAL, MEDLINE, Embase, LILACS and four trials registers, together with reference checking and contact with study authors to identify additional studies. We also handsearched proceedings from specific conferences from 2016 to 2020 inclusive.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of people with stage III and IV melanoma, comparing neoadjuvant treatment strategies (using targeted treatments, immunotherapies, radiotherapy, topical treatments or chemotherapy) with any of these agents or current standard of care (SOC), were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Primary outcomes were overall survival (OS) and adverse effects (AEs). Secondary outcomes included time to recurrence (TTR), quality of life (QOL), and overall response rate (ORR). We used GRADE to evaluate the certainty of the evidence.

MAIN RESULTS

We included eight RCTs involving 402 participants. Studies enrolled adults, mostly with stage III melanoma, investigated immunotherapies, chemotherapy, or targeted treatments, and compared these with surgical excision with or without adjuvant treatment. Duration of follow-up and therapeutic regimens varied, which, combined with heterogeneity in the population and definitions of the endpoints, precluded meta-analysis of all identified studies. We performed a meta-analysis including three studies. We are very uncertain if neoadjuvant treatment increases OS when compared to no neoadjuvant treatment (hazard ratio (HR) 0.43, 95% confidence interval (CI) 0.15 to 1.21; 2 studies, 171 participants; very low-certainty evidence). Neoadjuvant treatment may increase the rate of AEs, but the evidence is very uncertain (26% versus 16%, risk ratio (RR) 1.58, 95% CI 0.97 to 2.55; 2 studies, 162 participants; very low-certainty evidence). We are very uncertain if neoadjuvant treatment increases TTR (HR 0.51, 95% CI 0.22 to 1.17; 2 studies, 171 participants; very low-certainty evidence). Studies did not report ORR as a comparative outcome or measure QOL data. We are very uncertain whether neoadjuvant targeted treatment with dabrafenib and trametinib increases OS (HR 0.28, 95% CI 0.03 to 2.25; 1 study, 21 participants; very low-certainty evidence) or TTR (HR 0.02, 95% CI 0.00 to 0.22; 1 study, 21 participants; very low-certainty evidence) when compared to surgery. The study did not report comparative rates of AEs and overall response, and did not measure QOL. We are very uncertain if neoadjuvant immunotherapy with talimogene laherparepvec increases OS when compared to no neoadjuvant treatment (HR 0.49, 95% CI 0.15 to 1.64; 1 study, 150 participants, very low-certainty evidence). It may have a higher rate of AEs, but the evidence is very uncertain (16.5% versus 5.8%, RR 2.84, 95% CI 0.96 to 8.37; 1 study, 142 participants; very low-certainty evidence). We are very uncertain if it increases TTR (HR 0.75, 95% CI 0.31 to 1.79; 1 study, 150 participants; very low-certainty evidence). The study did not report comparative ORRs or measure QOL. OS was not reported for neoadjuvant immunotherapy (combined ipilimumab and nivolumab) when compared to the combination of ipilimumab and nivolumab as adjuvant treatment. There may be little or no difference in the rate of AEs between these treatments (9%, RR 1.0, 95% CI 0.75 to 1.34; 1 study, 20 participants; low-certainty evidence). The study did not report comparative ORRs or measure TTR and QOL. Neoadjuvant immunotherapy (combined ipilimumab and nivolumab) likely results in little to no difference in OS when compared to neoadjuvant nivolumab monotherapy (P = 0.18; 1 study, 23 participants; moderate-certainty evidence). It may increase the rate of AEs, but the certainty of this evidence is very low (72.8% versus 8.3%, RR 8.73, 95% CI 1.29 to 59; 1 study, 23 participants); this trial was halted early due to observation of disease progression preventing surgical resection in the monotherapy arm and the high rate of treatment-related AEs in the combination arm. Neoadjuvant combination treatment may lead to higher ORR, but the evidence is very uncertain (72.8% versus 25%, RR 2.91, 95% CI 1.02 to 8.27; 1 study, 23 participants; very low-certainty evidence). It likely results in little to no difference in TTR (P = 0.19; 1 study, 23 participants; low-certainty evidence). The study did not measure QOL. OS was not reported for neoadjuvant immunotherapy (combined ipilimumab and nivolumab) when compared to neoadjuvant sequential immunotherapy (ipilimumab then nivolumab). Only Grade 3 to 4 immune-related AEs were reported; fewer were reported with combination treatment, and the sequential treatment arm closed early due to a high incidence of severe AEs. The neoadjuvant combination likely results in a higher ORR compared to sequential neoadjuvant treatment (60.1% versus 42.3%, RR 1.42, 95% CI 0.87 to 2.32; 1 study, 86 participants; low-certainty evidence). The study did not measure TTR and QOL. No data were reported on OS, AEs, TTR, or QOL for the comparison of neoadjuvant interferon (HDI) plus chemotherapy versus neoadjuvant chemotherapy. Neoadjuvant HDI plus chemotherapy may have little to no effect on ORR, but the evidence is very uncertain (33% versus 22%, RR 1.75, 95% CI 0.62 to 4.95; 1 study, 36 participants; very low-certainty evidence).

AUTHORS' CONCLUSIONS

We are uncertain if neoadjuvant treatment increases OS or TTR compared with no neoadjuvant treatment, and it may be associated with a slightly higher rate of AEs. There is insufficient evidence to support the use of neoadjuvant treatment in clinical practice. Priorities for research include the development of a core outcome set for neoadjuvant trials that are adequately powered, with validation of pathological and radiological responses as intermediate endpoints, to investigate the relative benefits of neoadjuvant treatment compared with adjuvant treatment with immunotherapies or targeted therapies.

Candidate therapeutic agents in a newly established triple wild‐type mucosal melanoma cell line

Background

Mucosal melanoma has characteristically distinct genetic features and typically poor prognosis. The lack of representative mucosal melanoma models, especially cell lines, has hindered translational research on this melanoma subtype. In this study, we aimed to establish and provide the biological properties, genomic features and the pharmacological profiles of a mucosal melanoma cell line that would contribute to the understanding and treatment optimization of molecularly‐defined mucosal melanoma subtype.

Methods

The sample was collected from a 67‐year‐old mucosal melanoma patient and processed into pieces for the establishment of cell line and patient‐derived xenograft (PDX) model. The proliferation and tumorigenic property of cancer cells from different passages were evaluated, and whole‐genome sequencing (WGS) was performed on the original tumor, PDX, established cell line, and the matched blood to confirm the establishment and define the genomic features of this cell line. AmpliconArchitect was conducted to depict the architecture of amplified regions detected by WGS. High‐throughput drug screening (HTDS) assay including a total of 103 therapeutic agents was implemented on the established cell line, and selected candidate agents were validated in the corresponding PDX model.

Results

A mucosal melanoma cell line, MM9H‐1, was established which exhibited robust proliferation and tumorigenicity after more than 100 serial passages. Genomic analysis of MM9H‐1, corresponding PDX, and the original tumor showed genetic fidelity across genomes, and MM9H‐1 was defined as a triple wild‐type (TWT) melanoma subtype lacking well‐characterized “driver mutations”. Instead, the amplification of several oncogenes, telomerase reverse transcriptase (TERT), v‐Raf murine sarcoma viral oncogene homolog B1 (BRAF), melanocyte Inducing transcription factor (MITF) and INO80 complex ATPase subunit (INO80), via large‐scale genomic rearrangement potentially contributed to oncogenesis of MM9H‐1. Moreover, HTDS identified proteasome inhibitors, especially bortezomib, as promising therapeutic candidates for MM9H‐1, which was verified in the corresponding PDX model in vivo.

Conclusions

We established and characterized a new mucosal melanoma cell line, MM9H‐1, and defined this cell line as a TWT melanoma subtype lacking well‐characterized “driver mutations”. The MM9H‐1 cell line could be adopted as a unique model for the preclinical investigation of mucosal melanoma.

Managing Metastatic Melanoma in 2022: A Clinical Review

Cutaneous melanoma remains the most lethal of the primary cutaneous neoplasms, and although the incidence of primary melanoma continues to rise, the mortality from metastatic disease remains unchanged, in part through advances in treatment. Major developments in immunomodulatory and targeted therapies have provided robust improvements in response and survival trends that have transformed the clinical management of patients with metastatic melanoma. Additional advances in immunologic and cancer cell biology have contributed to further optimization in (1) risk stratification, (2) prognostication, (3) treatment, (4) toxicity management, and (5) surveillance approaches for patients with an advanced melanoma diagnosis. In this review, we provide a comprehensive overview of the historical and future advances regarding the translational and clinical implications of advanced melanoma and share multidisciplinary recommendations to aid clinicians in the navigation of current treatment approaches for a variety of patient cohorts.

Toripalimab plus axitinib in patients with metastatic mucosal melanoma: 3-year survival update and biomarker analysis

BACKGROUND

Mucosal melanoma is an aggressive melanoma subtype with poor response to antiprogrammed cell death-1 (PD-1) monotherapy. Axitinib in combination with toripalimab, a humanized IgG4 mAb against PD-1, showed a promising response rate in patients with metastatic mucosal melanoma (MM) in a phase Ib study. Here, we report the updated overall survival (OS), duration of response (DoR), and biomarker analysis results.

METHODS

Patients with advanced MM received toripalimab 1 or 3 mg/kg intravenously every 2 weeks combined with axitinib 5 mg orally two times per day until disease progression or unacceptable toxicity. Tumor programmed cell death ligand-1 (PD-L1) expression, tumor mutational burden (TMB), and gene expression profile (GEP) by messenger RNA sequencing were evaluated for correlation with survival.

RESULTS

As of April 2, 2021, the median follow-up was 42.5 months. Among 29 chemotherapy-naïve patients with metastatic MM, the median OS was 20.7 months (95% CI 9.7 to 32.7 months); the median progression-free survival (PFS) was 7.5 months (95% CI 3.8 to 14.8 months); and the median DoR was 13.4 months (95% CI 5.5 to 20.6 months). The OS rates of 1, 2, and 3 years were 62.1%, 44.8%, and 31.0%, respectively. Biomarker analysis found that PD-L1 expression and TMB level were not associated with survival benefits. In contrast, a 12-GEP signature correlated with improved PFS (17.7 vs 5.7 months, p=0.0083) and OS (35.6 vs 17.6 months, p=0.039).

CONCLUSIONS

The 3-year survival update confirmed the antitumor activity and long-term survival benefit of the toripalimab plus axitinib combination in patients with advanced MM. The 12-gene GEP is of value in predicting the outcomes of vascular endothelial growth factor receptor-tyrosine kinase inhibitor and PD-1 blockade combination therapy, but requires further validation.

TRIAL REGISTRATION NUMBERS

NCT03086174.

Molecular Markers and Targets in Melanoma

Melanoma develops as a result of several genetic alterations, with UV radiation often acting as a mutagenic risk factor. Deep knowledge of the molecular signaling pathways of different types of melanoma allows better characterization and provides tools for the development of therapies based on the intervention of signals promoted by these cascades. The latest World Health Organization classification acknowledged the specific genetic drivers leading to melanoma and classifies melanocytic lesions into nine distinct categories according to the associate cumulative sun damage (CSD), which correlates with the molecular alterations of tumors. The largest groups are melanomas associated with low-CSD or superficial spreading melanomas, characterized by frequent presentation of the BRAFV600 mutation. High-CSD melanomas include lentigo maligna type and desmoplastic melanomas, which often have a high mutation burden and can harbor NRAS, BRAFnon-V600E, or NF1 mutations. Non-CSD-associated melanomas encompass acral and mucosal melanomas that usually do not show BRAF, NRAS, or NF1 mutations (triple wild-type), but in a subset may have KIT or SF3B1 mutations. To improve survival, these driver alterations can be treated with targeted therapy achieving significant antitumor activity. In recent years, relevant improvement in the prognosis and survival of patients with melanoma has been achieved, since the introduction of BRAF/MEK tyrosine kinase inhibitors and immune checkpoint inhibitors. In this review, we describe the current knowledge of molecular pathways and discuss current and potential therapeutic targets in melanoma, focusing on their clinical relevance of development.

Current Perspectives and Novel Strategies of NRAS-Mutant Melanoma

Melanoma is the deadliest cutaneous cancer. Activating mutations in NRAS are found in 20% of melanomas. NRAS-mutant melanoma is more aggressive and, therefore, has poorer outcomes, compared to non-NRAS-mutant melanoma. Despite promising preclinical data, to date immune checkpoint inhibitors remain the standard of care for locally advanced unresectable or metastatic NRAS melanoma. Data for efficacy of immunotherapy for NRAS melanoma mainly come from retrospective cohorts with divergent conclusions. MEK inhibitors have been the most developed targeted therapy approach. Although associated with an increase in progression-free survival, MEK inhibitors do not provide any benefit in terms of overall survival. Combination strategies with PI3K-AKT-mTOR pathway and CDK4/6 inhibitors seem to increase MEK inhibitors' benefit. Nevertheless, results from clinical trials are still prelaminar. A greater comprehension of the biology and intracellular interactions of NRAS-mutant melanoma will outline novel impactful strategies which could improve prognosis of these subgroup of patients.

Hypoxia-dependent drivers of melanoma progression

Hypoxia, a condition of low oxygen availability, is a hallmark of tumour microenvironment and promotes cancer progression and resistance to therapy. Many studies reported the essential role of hypoxia in regulating invasiveness, angiogenesis, vasculogenic mimicry and response to therapy in melanoma. Melanoma is an aggressive cancer originating from melanocytes located in the skin (cutaneous melanoma), in the uveal tract of the eye (uveal melanoma) or in mucosal membranes (mucosal melanoma). These three subtypes of melanoma represent distinct neoplasms in terms of biology, epidemiology, aetiology, molecular profile and clinical features.In this review, the latest progress in hypoxia-regulated pathways involved in the development and progression of all melanoma subtypes were discussed. We also summarized current knowledge on preclinical studies with drugs targeting Hypoxia-Inducible Factor-1, angiogenesis or vasculogenic mimicry. Finally, we described available evidence on clinical studies investigating the use of Hypoxia-Inducible Factor-1 inhibitors or antiangiogenic drugs, alone or in combination with other strategies, in metastatic and adjuvant settings of cutaneous, uveal and mucosal melanoma.Hypoxia-Inducible Factor-independent pathways have been also reported to regulate melanoma progression, but this issue is beyond the scope of this review.As evident from the numerous studies discussed in this review, the increasing knowledge of hypoxia-regulated pathways in melanoma progression and the promising results obtained from novel antiangiogenic therapies, could offer new perspectives in clinical practice in order to improve survival outcomes of melanoma patients.

RTK Inhibitors in Melanoma: From Bench to Bedside

MAPK (mitogen activated protein kinase) and PI3K/AKT (Phosphatidylinositol-3-Kinase and Protein Kinase B) pathways play a key role in melanoma progression and metastasis that are regulated by receptor tyrosine kinases (RTKs). Although RTKs are mutated in a small percentage of melanomas, several receptors were found up regulated/altered in various stages of melanoma initiation, progression, or metastasis. Targeting RTKs remains a significant challenge in melanoma, due to their variable expression across different melanoma stages of progression and among melanoma subtypes that consequently affect response to treatment and disease progression. In this review, we discuss in details the activation mechanism of several key RTKs: type III: c-KIT (mast/stem cell growth factor receptor); type I: EGFR (Epidermal growth factor receptor); type VIII: HGFR (hepatocyte growth factor receptor); type V: VEGFR (Vascular endothelial growth factor), structure variants, the function of their structural domains, and their alteration and its association with melanoma initiation and progression. Furthermore, several RTK inhibitors targeting the same receptor were tested alone or in combination with other therapies, yielding variable responses among different melanoma groups. Here, we classified RTK inhibitors by families and summarized all tested drugs in melanoma indicating the rationale behind the use of these drugs in each melanoma subgroups from preclinical studies to clinical trials with a specific focus on their purpose of treatment, resulted effect, and outcomes.

Nuances to precision dosing strategies of targeted cancer medicines

Selecting the dose of a targeted cancer medicine that is most appropriate for a specific individual is a rational approach to maximize therapeutic outcomes and minimize toxicity. There are many different options for optimizing the dose of targeted cancer medicines and the purpose of this review is to provide a comprehensive comparison of the main options explored in prospective studies. Precision initial dose selection of targeted cancer therapies has been minimally explored to date; however, concentration, toxicity, and therapeutic outcome markers are used to guide on-therapy dose adaption of targeted cancer therapies across several medicines and cancers. While a specific concentration, toxicity, or therapeutic outcome marker commonly dominates an investigated precision on-therapy dose adaption strategy, greater attention to simultaneously account for exposure, toxicity, therapeutic outcomes, disease status, time since treatment initiation and patient preferences are required for optimal patient outcomes. To enable successful implementation of precision dosing strategies for targeted cancer medicines into clinical practice, future prospective studies aiming to develop strategies should consider these elements in their design.

Glioblastoma Cells Do Not Affect Axitinib-Dependent Senescence of HUVECs in a Transwell Coculture Model

Axitinib is an orally available inhibitor of tyrosine kinases, with high specificity for vascular endothelial growth factor receptors (VEGFRs) 1, 2, and 3. It is approved for the treatment of advanced renal cell carcinoma and is in phase II clinical trials for recurrent glioblastoma (GBM). GBM is a brain tumor peculiar in its ability to induce neoangiogenesis. Since both GBM tumor cells and endothelial cells of tumor vasculature express VEGFRs, Axitinib exerts its inhibitory action on both tumor and endothelial cells. We and others previously demonstrated that Axitinib triggers cellular senescence. In particular, Axitinib-dependent senescence of HUVECs (human umbilical vein endothelial cells) is accompanied by intracellular reactive oxygen species(ROS) increase and early ataxia telangiectasia mutated(ATM) activation. Here we wondered if the presence of glioblastoma tumor cells could affect the HUVEC senescence upon Axitinib exposure. To address this issue, we cocultured HUVECs together with GBM tumor cells in transwell plates. HUVEC senescence did not result in being affected by GBM cells, neither in terms of β galactosidase activity nor of proliferation index or ATM phosphorylation. Conversely, Axitinib modulation of HUVEC gene expression was altered by cocultured GBM cells. These data demonstrate that the GBM secretome modifies HUVECs’ transcriptomic profile upon Axitinib exposure, but does not prevent drug-induced senescence.

Uveal Melanoma, Angiogenesis and Immunotherapy, Is There Any Hope?

Uveal melanoma is considered a rare disease but it is the most common intraocular malignancy in adults. Local treatments are effective, but the systemic recurrence rate is unacceptably high. Moreover, once metastasis have developed the prognosis is poor, with a 5-year survival rate of less than 5%, and systemic therapies, including immunotherapy, have rendered poor results. The tumour biology is complex, but angiogenesis is a highly important pathway in these tumours. Vasculogenic mimicry, the ability of melanomas to generate vascular channels independently of endothelial cells, could play an important role, but no effective therapy targeting this process has been developed so far. Angiogenesis modulates the tumour microenvironment of melanomas, and a close interplay is established between them. Therefore, combining immune strategies with drugs targeting angiogenesis offers a new therapeutic paradigm. In preclinical studies, these approaches effectively target these tumours, and a phase I clinical study has shown encouraging results in cutaneous melanomas. In this review, we will discuss the importance of angiogenesis in uveal melanoma, with a special focus on vasculogenic mimicry, and describe the interplay between angiogenesis and the tumour microenvironment. In addition, we will suggest future therapeutic approaches based on these observations and mention ways in which to potentially enhance current treatments.

Gene expression and promoter methylation of angiogenic and lymphangiogenic factors as prognostic markers in melanoma

The high mortality rate of melanoma is broadly associated with its metastatic potential. Tumor cell dissemination is strictly dependent on vascularization; therefore, angiogenesis and lymphangiogenesis play an essential role in metastasis. Hence, a better understanding of the players of tumor vascularization and establishing them as new molecular biomarkers might help to overcome the poor prognosis of melanoma patients. Here, we further characterized a linear murine model of melanoma progression and showed that the aggressiveness of melanoma cells is closely associated with high expression of angiogenic factors, such as Vegfc, Angpt2, and Six1, and that blockade of the vascular endothelial growth factor pathway by the inhibitor axitinib abrogates their tumorigenic potential in vitro and in the in vivo chicken chorioallantoic membrane assay. Furthermore, analysis of The Cancer Genome Atlas data revealed that the expression of the angiogenic factor ANGPT2 (P‐value = 0.044) and the lymphangiogenic receptor VEGFR‐3 (P‐value = 0.002) were independent prognostic factors of overall survival in melanoma patients. Enhanced reduced representation bisulfite sequencing‐based methylome profiling revealed for the first time a link between abnormal VEGFC, ANGPT2, and SIX1 gene expression and promoter hypomethylation in melanoma cells. In patients, VEGFC (P‐value = 0.031), ANGPT2 (P‐value < 0.001), and SIX1 (P‐value = 0.009) promoter hypomethylation were independent prognostic factors of shorter overall survival. Hence, our data suggest that these angio‐ and lymphangiogenesis factors are potential biomarkers of melanoma prognosis. Moreover, these findings strongly support the applicability of our melanoma progression model to unravel new biomarkers for this aggressive human disease.

Antitumor effect of axitinib combined with dopamine and PK-PD modeling in the treatment of human breast cancer xenograft

Rising evidence has shown the development of resistance to vascular endothelial growth factor receptor (VEGFR) inhibitors in the practices of cancer therapy. It is reported that the efficacy of axitinib (AX), a VEGFR inhibitor, is limited in the treatment of breast cancer as a single agent or in combination with other chemotherapeutic drugs due to the probability of rising population of cancer stem-like cells (CSCs) caused by AX. The present study evaluated the effect of dopamine (DA) improving AX's efficacy on MCF-7/ADR breast cancer in vitro and in vivo, and developed a pharmacokinetic-pharmacodynamic (PK-PD) model describing the in vivo experimental data and characterizing the interaction of effect between AX and DA. The results showed that AX up-regulated the expression of breast CSC (BCSC) markers (CD44⁺/CD24^-/low) in vivo, and DA significantly synergized the inhibitory effect on tumor growth by deducting the BCSC frequency. The PK-PD model quantitatively confirmed the synergistic interaction with the parameter estimate of interaction factor ψ 2.43. The dose regimen was optimized as 60 mg/kg AX i.g. b.i.d. combined with 50 mg/kg DA i.p. q3d in the simulation study on the basis of the PK-PD model. The model where DA synergistically enhances the effect of AX in an all-or-none manner provides a possible solution in modeling the agents like DA. Moreover, the outcome of AX and DA combination therapy in MCF-7/ADR breast cancer provided further insight of co-administering DA in the treatment of the possible CSC-causing AX-resisting breast cancer. And this combination therapy has the prospect of clinical translation.

A study of axitinib, a VEGF receptor tyrosine kinase inhibitor, in children and adolescents with recurrent or refractory solid tumors: A Children's Oncology Group phase 1 and pilot consortium trial (ADVL1315)

BACKGROUND

Axitinib is an oral small molecule that inhibits receptor tyrosine kinases vascular endothelial growth factor receptors 1 to 3. A phase 1 and pharmacokinetic (PK) trial evaluating axitinib was conducted in children with refractory solid tumors.

METHODS

Axitinib was administered orally twice daily in continuous 28-day cycles. Dose levels (2.4 mg/m² /dose and 3.2 mg/m² /dose) were evaluated using a rolling 6 design. Serial PKs (cycle 1, days 1 and 8) and exploratory biomarkers were analyzed.

RESULTS

A total of 19 patients were enrolled; 1 patient was ineligible due to inadequate time having elapsed from prior therapy. The median age of the patients was 13.5 years (range, 5-17 years). Two of 5 patients who were treated at dose level 2 experienced dose-limiting toxicities (palmar-plantar erythryodysesthesia syndrome in 1 patient and intratumoral hemorrhage in 1 patient). Frequent (>20%) grade 1 to 2 toxicities during cycle 1 included anemia, anorexia, fatigue, diarrhea, nausea, and hypertension. Nonhematological toxicities of grade ≥3 in subsequent cycles included hypertension and elevated serum lipase. PK analysis demonstrated variability in axitinib exposure, the median time to peak plasma concentration was 2 hours, and the half-life ranged from 0.7 to 5.2 hours. Exposure and dose were not found to be significantly associated with hypertension. Five patients achieved stable disease for ≤6 cycles as their best response, including patients with malignant peripheral nerve sheath tumor (1 patient), Ewing sarcoma (1 patient), hepatocellular carcinoma (1 patient), and osteosarcoma (2 patients). One patient with alveolar soft part sarcoma achieved a partial response. Kidney injury biomarkers were found to be elevated at baseline; no trends were identified.

CONCLUSIONS

In children with refractory solid tumors, the maximum tolerated and recommended dose of axitinib appears to be 2.4 mg/m² /dose, which provides PK exposures similar to those of adults.

Phase II study of pazopanib in combination with paclitaxel in patients with metastatic melanoma

PURPOSE

This phase II study evaluated the safety and clinical activity of pazopanib, a potent and mutlitargeted tyrosine kinase inhibitor (TKI) of vascular endothelial growth factor receptors (VEGFRs)-1, -2 and -3, platelet-derived growth factor receptor (PDGFR)-α and β, and cKit, in combination with metronomic paclitaxel in patients with metastatic melanoma.

EXPERIMENTAL DESIGN

Sixty chemotherapy-naive patients received pazopanib at a starting dose of 800 mg daily in combination with metronomic dosing of paclitaxel 80 mg/m² weekly thrice every 4 weeks. The primary endpoint was 6-month progression-free survival (PFS) rate, while secondary endpoints included 1-year overall survival rate, RECIST response rates, progression-free survival rates and median overall survival. Prior BRAF-targeted therapy or checkpoint inhibitors were permitted.

RESULTS

The 6-month PFS rate was 68%, with a 1-year OS rate of 48%. Objective response rate was 37% comprising one complete and 20 partial responses. Stable disease at 8 weeks was noted in 32 patients (55%) with an overall clinical benefit rate of 93%. Six-month median progression-free survival was 8 months and median OS was 12.7 months. The most frequently (> 15%) reported non-hematologic, treatment-related adverse events were fatigue, diarrhea, hypertension, transaminitis and peripheral neuropathy. Treatment-related non-fatal bowel perforation, a known class effect, occurred in one patient. No significant association was noted between plasma levels of pazopanib and response.

CONCLUSIONS

The combination of pazopanib and metronomic paclitaxel was well-tolerated, demonstrating significant activity in metastatic melanoma. Further evaluation of this combination is warranted.

The Versatile Tanycyte: A Hypothalamic Integrator of Reproduction and Energy Metabolism

The fertility and survival of an individual rely on the ability of the periphery to promptly, effectively, and reproducibly communicate with brain neural networks that control reproduction, food intake, and energy homeostasis. Tanycytes, a specialized glial cell type lining the wall of the third ventricle in the median eminence of the hypothalamus, appear to act as the linchpin of these processes by dynamically controlling the secretion of neuropeptides into the portal vasculature by hypothalamic neurons and regulating blood-brain and blood-cerebrospinal fluid exchanges, both processes that depend on the ability of these cells to adapt their morphology to the physiological state of the individual. In addition to their barrier properties, tanycytes possess the ability to sense blood glucose levels, and play a fundamental and active role in shuttling circulating metabolic signals to hypothalamic neurons that control food intake. Moreover, accumulating data suggest that, in keeping with their putative descent from radial glial cells, tanycytes are endowed with neural stem cell properties and may respond to dietary or reproductive cues by modulating hypothalamic neurogenesis. Tanycytes could thus constitute the missing link in the loop connecting behavior, hormonal changes, signal transduction, central neuronal activation and, finally, behavior again. In this article, we will examine these recent advances in the understanding of tanycytic plasticity and function in the hypothalamus and the underlying molecular mechanisms. We will also discuss the putative involvement and therapeutic potential of hypothalamic tanycytes in metabolic and fertility disorders.

Prognostic and Predictive Factors for Renal Cell Carcinoma

Metastatic renal cell carcinoma (mRCC) is an incurable malignancy, characterized by its resistance to traditional chemotherapy, radiation, and hormonal therapy. Treatment perspectives and prognosis of patients with mRCC have been significantly improved by advances in the understanding of its molecular pathogenesis, which have led to the development of targeted therapeutics. Different molecular factors derived from the tumor or the host detected in both tissue or serum could be predictive of therapeutic benefit. Some of them suggest a rational selection of patients to be treated with certain therapies, though none have been validated for routine use. This article provides an overview of both clinical and molecular factors associated with predictive or prognostic value in mRCC and emphasizes that both should be considered in parallel to provide the most appropriate, individualized treatment and achieve the best outcomes in clinical practice.

A Randomized Phase II Study of Axitinib as Maintenance Therapy After First-line Treatment for Metastatic Colorectal Cancer

INTRODUCTION

The aim of this study was to evaluate the efficacy and safety of maintenance therapy with axitinib versus placebo following induction therapy in patients with metastatic colorectal cancer (mCRC).

PATIENTS AND METHODS

In this double-blinded, phase II trial, patients with mCRC who had not progressed after 6 to 8 months of first-line chemotherapy were randomized to receive axitinib (5 mg twice a day) (arm A) or placebo (arm B).

RESULTS

Forty-nine patients were included: 25 in arm A and 24 in arm B. The median follow-up was 26.07 months (95% confidence interval [CI], 18.44-31.73 months). Progression-free survival (PFS) rate at 6 months was 40.00% (95% CI, 21.28%-58.12%) in the axitinib arm versus 8.33% (95% CI, 1.44%-23.30%) in the placebo arm (P = .0141). The median PFS was statistically significantly longer in the axitinib group than in the placebo group (4.96 vs. 3.16 months; hazard ratio, 0.46; 95% CI, 0.25-0.86; P = .0116). Median overall survival was also longer in the axitinib arm but did not reach statistical significance (27.61 vs. 19.99 months; hazard ratio, 0.68; 95% CI, 0.31-1.48; P = .3279). Grade 3 to 4 treatment-related toxicities were experienced by 7 patients (28%) in cohort A and 1 patient (4%) in cohort B (P = .0488). The most frequent grade 3 to 4 treatment-related toxicities were hypertension, diarrhea, and asthenia. There were no toxic deaths. The study was prematurely closed because of slow recruitment.

CONCLUSIONS

In our study, maintenance treatment with axitinib monotherapy showed a significant increase in PFS and a good safety profile. Axitinib should be further explored as a possible option for first-line chemotherapy maintenance treatment in patients with mCRC.

A first-in-human phase I, multicenter, open-label, dose-escalation study of the oral RAF/VEGFR-2 inhibitor (RAF265) in locally advanced or metastatic melanoma independent from BRAF mutation status

To establish the maximum tolerated dose (MTD), dose‐limiting toxicities (DLT), safety profile, and anti‐tumor efficacy of RAF265. We conducted a multicenter, open‐label, phase‐I, dose‐escalation trial of RAF265, an orally available RAF kinase/VEGFR‐2 inhibitor, in patients with advanced or metastatic melanoma. Pharmacokinetic (PK) analysis, pharmacodynamics (PD) and tumor response assessment were conducted. We evaluated metabolic tumor response by 18[F]‐fluorodeoxyglucose‐positron‐emission tomography (FDG‐PET), tissue biomarkers using immunohistochemistry (IHC), and modulators of angiogenesis. RAF265 has a serum half‐life of approximately 200 h. The MTD was 48 mg once daily given continuously. Among 77 patients, most common treatment‐related adverse effects were fatigue (52%), diarrhea (34%), weight loss (31%) and vitreous floaters (27%). Eight of 66 evaluable patients (12.1%) had an objective response, including seven partial and one complete response. Responses occurred in BRAF‐mutant and BRAF wild‐type (WT) patients. Twelve of 58 (20.7%) evaluable patients had a partial metabolic response. On‐treatment versus pretreatment IHC staining in 23 patients showed dose‐dependent p‐ERK inhibition. We observed a significant temporal increase in placental growth factor levels and decrease in soluble vascular endothelial growth factor receptor 2 (sVEGFR‐2) levels in all dose levels. RAF265 is an oral RAF/VEGFR‐2 inhibitor that produced antitumor responses, metabolic responses, and modulated angiogenic growth factor levels. Antitumor activity occurred in patients with BRAF‐mutant and BRAF‐WT disease. Despite low activity at tolerable doses, this study provides a framework for the development of pan‐RAF inhibitors and modulators of angiogenesis for the treatment of melanoma.

Emerging growth factor receptor antagonists for the treatment of advanced melanoma

INTRODUCTION

Therapy for metastatic melanoma has undergone a rapid transformation over the past 5-10 years. Advances in immunotherapy with checkpoint inhibitors, including both anti-CTLA-4 and anti-PD-1/PD-L1, have led to durable responses in up to 50% of patients. As our understanding of the processes driving the transformation of melanocytes has improved, progress in targeted therapies has also continued. Areas covered: Angiogenesis and the tumor's dependence on an expanded vascular supply has been a target for novel therapies since the 1970's, as this tissue is derived from endothelial cells that are genetically stable in adults. A phase II trial studying combined therapy with bevacizumab (an inhibitor of angiogenesis) and ipilimumab found promising results. Other agents such as sorafenib have not been as successful, failing to extend progression free or overall survival in clinical trials. In this paper other targeted growth factor inhibitors will also be discussed. Expert opinion: Ultimately, melanoma may not be vulnerable solely to chemotherapy or targeted therapy, but may be efficaciously treated with immunotherapy due to its high mutational rate resulting in the expression of numerous neo-antigens. Therapies with combinations of agents including growth factor receptor and either other targeted therapies or immunotherapy may be a promising complimentary approach.

Treatment of NRAS-mutated advanced or metastatic melanoma: rationale, current trials and evidence to date

The disease course of BRAF (v-raf murine sarcoma viral oncogene homolog B1)-mutant melanoma has been drastically improved by the arrival of targeted therapies. NRAS (neuroblastoma RAS viral oncogene homolog)-mutated melanoma represents 15–25% of all metastatic melanoma patients. It currently does not have an approved targeted therapy. Metastatic patients receive immune-based therapies as first-line treatments, then cytotoxic chemotherapy like carboplatin/paclitaxel (C/P), dacarbazine (DTIC) or temozolomide (TMZ) as a second-line treatment. We will review current preclinical and clinical developments in NRAS-mutated melanoma, and analyze ongoing clinical trials that are evaluating the benefit of different targeted and immune-based therapies, either tested as single agents or in combination, in NRAS-mutant melanoma.

Evolving systemic targeted therapy strategies in uveal melanoma and implications for ophthalmic management: a review

Uveal melanoma (UM) is the most common primary ocular tumour in adults. Despite good local control of the primary tumour with current methods, survival after the development of metastasis has remained poor over the last 30 years. After cutaneous melanoma, UM is the most common type of melanoma, and an ongoing debate exists regarding whether these conditions should be considered separate entities, particularly in the context of targeted therapy, where many of the initial trials for patients with metatatic cutaneous melanoma excluded metastatic UM. This paper will review the recent and ongoing investigations designed to validate systemic targeted therapy and immunotherapy in patients with metastatic UM and suggests ways in which these developments may affect management of UM by ophthalmologists in the near future.

Hepatocellular carcinoma: Will novel targeted drugs really impact the next future?

Cancer treatment has been revolutionized by the advent of new molecular targeted and immunotherapeutic agents. Identification of the role of tumor angiogenesis changed the understanding of many tumors. After the unsuccessful results with chemotherapy, sorafenib, by interfering with angiogenic pathways, has become pivotal in the treatment of hepatocellular carcinoma. Sorafenib is the only systemic treatment to show a modest but statistically significant survival benefit. All novel drugs and strategies for treatment of advanced hepatocellular carcinoma must be compared with the results obtained with sorafenib, but no new drug or drug combination has yet achieved better results. In our opinion, the efforts to impact the natural history of the disease will be directed not only to drug development but also to understanding the underlying liver disease (usually hepatitis B virus- or hepatitis C virus-related) and to interrupting the progression of cirrhosis. It will be important to define the role and amount of mutations in the complex pathogenesis of hepatocellular carcinoma and to better integrate locoregional and systemic therapies. It will be important also to optimize the therapeutic strategies with existing chemotherapeutic drugs and new targeted agents.

Angiogenesis in melanoma: an update with a focus on current targeted therapies

Angiogenesis plays a crucial role in melanoma metastasis and progression. In recent years, numerous studies have investigated the prognostic and clinical significance of this phenomenon, and the development of molecular techniques has enabled us to achieve a better understanding of angiogenesis in melanoma. Herein, we review the current state of knowledge regarding angiogenesis in melanoma, including the pathophysiological, histological and immunohistochemical aspects of this phenomenon. We also review the molecular pathways involved in angiogenesis and the interplay between different components that might be manipulated in the future development of efficient targeted therapies. Recently developed targeted antiangiogenic therapies in clinical trials and included in the treatment of advanced-stage melanoma are also reviewed.

Spheroid-plug model as a tool to study tumor development, angiogenesis, and heterogeneity in vivo

Subcutaneous injection of the tumor cell suspension is a simple and commonly used tool for studying tumor development in vivo. However, subcutaneous models poorly resemble tumor complexity due to the fast growth not reflecting the natural course. Here, we describe an application of the new spheroid-plug model to combine the simplicity of subcutaneous injection with improved resemblance to natural tumor progression. Spheroid-plug model relies on in vitro formation of tumor spheroids, followed by injection of single tumor spheroid subcutaneously in Matrigel matrix. In spheroid-plug model, tumors grow slower in comparison to tumors formed by injection of cell suspension as assessed by 3D ultrasonography (USG) and in vivo bioluminescence measurements. The slower tumor growth rate in spheroid-plug model is accompanied by reduced necrosis. The spheroid-plug model ensures increased and more stable vascularization of tumor than classical subcutaneous tumor model as demonstrated by 3D USG Power Doppler examination. Flow cytometry analysis showed that tumors formed from spheroids have enhanced infiltration of endothelial cells as well as hematopoietic and progenitor cells with stem cell phenotype (c-Kit(+) and Sca-1(+)). They also contain more tumor cells expressing cancer stem cell marker CXCR4. Here, we show that spheroid-plug model allows investigating efficiency of anticancer drugs. Treatment of spheroid-plug tumors with known antiangiogenic agent axitinib decreased their size and viability. The antiangiogenic activity of axitinib was higher in spheroid-plug model than in classical model. Our results indicate that spheroid-plug model imitates natural tumor growth and can become a valuable tool for cancer research.

Metastatic melanoma treatment: Combining old and new therapies

Metastatic melanoma is an aggressive form of cancer characterised by poor prognosis and a complex etiology. Until 2010, the treatment options for metastatic melanoma were very limited. Largely ineffective dacarbazine, temozolamide or fotemustine were the only agents in use for 35 years. In recent years, the development of molecularly targeted inhibitors in parallel with the development of checkpoint inhibition immunotherapies has rapidly improved the outcomes for metastatic melanoma patients. Despite these new therapies showing initial promise; resistance and poor duration of response have limited their effectiveness as monotherapies. Here we provide an overview of the history of melanoma treatment, as well as the current treatments in development. We also discuss the future of melanoma treatment as we go beyond monotherapies to a combinatorial approach. Combining older therapies with the new molecular and immunotherapies will be the most promising way forward for treatment of metastatic melanoma.

Long-Term Safety With Axitinib in Previously Treated Patients With Metastatic Renal Cell Carcinoma

BACKGROUND

Axitinib is an approved treatment for advanced renal cell carcinoma (RCC) after failure of 1 systemic therapy.

PATIENTS AND METHODS

Long-term safety with single-agent axitinib was analyzed using pooled data from clinical trials in 672 previously treated patients with metastatic RCC (mRCC) and in 1304 patients with different advanced solid tumors. In all studies, except the phase I first-in-human, dose-finding study, the starting dose of oral axitinib was 5 mg twice daily continuously. Common long-term treatment-emergent adverse events (AEs) were identified in patients who received axitinib for ≥ 2 years, then evaluated in all patients, and assessed using interval, cumulative, and latency analyses.

RESULTS

In all, 108 (16%) previously treated patients with mRCC received axitinib for ≥ 2 years. In interval analysis, most AEs occurred during the first 6 months of treatment, with rates stable or decreased over time; rates increased for proteinuria, peripheral edema, and increased blood creatinine. Common Grade ≥ 3 AE rates declined or plateaued over time, except for increased amylase and myocardial infarction. Results were similar in cumulative analysis in this population, and in interval and cumulative analyses in all patients with mRCC and those with advanced solid tumors.

CONCLUSION

Declining or stable rates of most AEs support an acceptable long-term safety profile for axitinib in patients with mRCC. However, increases in the rates of some AEs warrant monitoring. This analysis is limited in that it was retrospective and included a relatively small patient population.

Vascular endothelial growth factor receptor tyrosine kinase inhibitors versus bevacizumab in metastatic colorectal cancer: A systematic review and meta-analysis

Bevacizumab has demonstrated a survival benefit in patients with metastatic colorectal cancer (mCRC) when combined with chemotherapy. Several randomized clinical trials comparing the efficacy and toxicity of vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitors (TKIs) against bevacizumab have been reported. The present meta-analysis was conducted to identify the potentially significant benefit of the combined treatment regimens in patients with mCRC. PubMed, Embase and Cochrane Library databases were searched for the randomized controlled trials published on or before September 2014, which compared the efficacy and toxicity of VEGFR TKIs with bevacizumab in combination with chemotherapy in patients with mCRC. The primary endpoints included progression-free survival (PFS), overall survival (OS) and overall response rate (ORR), and secondary endpoints were the toxicity profiles. Relative risks (RRs) with 95% confidence intervals (CIs) for response rate and adverse events (AEs) were calculated, as well as hazard ratios (HRs) for PFS and OS. The final analysis included 4 studies comprising a total of 1,929 intent-to-treat patients with mCRC, which compared VEGFR TKIs (cediranib and axitinib) plus chemotherapy with bevacizumab plus chemotherapy. Results demonstrated that VEGFR TKIs plus chemotherapy significantly resulted in a modest but significantly shorter PFS [hazard ratio (HR), 1.12; 95% CI, 1.00-1.25; P=0.05] compared with that of bevacizumab plus chemotherapy but not in OS (HR, 1.10; 95% CI, 0.88-1.17; P=0.87) and ORR (RR, 0.95; 95% CI, 0.85-1.05; P=0.30). VEGFR TKIs treatment showed a less favorable AE profile compared with bevacizumab, with higher rates of grade-III/IV diarrhea, fatigue, hypertension, neutropenia and thrombocytopenia, whereas a higher incidence of peripheral neuropathy associated with the bevacizumab group was observed. In conclusion, the addition of VEGFR TKIs to chemotherapy resulted in a modest but significantly shorter PFS but not in OS and ORR compared with bevacizumab. The VEGFR TKIs group showed a less favorable AE profile with higher rates of diarrhea, fatigue, hypertension, neutropenia and thrombocytopenia, whereas a higher incidence of peripheral neuropathy associated with the bevacizumab was observed.

The combination of axitinib followed by paclitaxel/carboplatin yields extended survival in advanced BRAF wild-type melanoma: results of a clinical/correlative prospective phase II clinical trial

BACKGROUND

Simultaneous chemotherapy with vascular endothelial growth factor (VEGF) inhibition has not shown additional benefit over chemotherapy alone in advanced melanoma. We tested administration of the potent VEGF inhibitor axitinib followed by paclitaxel/carboplatin to determine whether enhanced tumour proliferation during axitinib withdrawal leads to sustained chemosensitivity.

METHODS

We conducted a prospective phase II trial in metastatic melanoma patients with ECOG performance status 0-1 and normal organ function. Axitinib 5 mg PO b.i.d. was taken on days 1-14 of each 21-day treatment cycle, and carboplatin (AUC=5) with paclitaxel (175 mg m(-2)) was administered on day 1 starting with cycle 2. 3'-Deoxy-3'-(18)F-fluorothymidine ((18)F-FLT)-PET scans were performed in five patients to assess tumour proliferation on days 1, 14, 17, and 20 of cycle 1. Molecular profiling for BRAF was performed for all patients with cutaneous, acral, or mucosal melanoma.

RESULTS

The treatment was well tolerated. The most common grade 3 AEs were hypertension, neutropenia, and anaemia. Grade 4 non-haematologic AEs were not observed. Four of five patients completing (18)F-FLT-PET scans showed increases (23-92%) in SUV values during the axitinib holiday. Of 36 evaluable patients, there were 8 confirmed PRs by Response Evaluation Criteria in Solid Tumors. Overall, 20 patients had SD and 8 had PD as the best response. The median PFS was 8.7 months and the median overall survival was 14.0 months. Five BRAF(V600E/K) patients had significantly worse PFS than patients without these mutations.

CONCLUSIONS

Axitinib followed by carboplatin and paclitaxel was well tolerated and effective in BRAF wild-type metastatic melanoma. 3'-Deoxy-3'-(18)F-fluorothymidine-PET scans showed increased proliferation during axitinib withdrawal.

Receptor tyrosine kinase inhibitors: Are they real tumor killers?

Inhibiting tumor growth by targeting the tumor vasculature was first proposed by Judah Folkman almost 40 years ago. Since then, different approaches and numerous drugs and agents have been developed to achieve this goal, either with the aim of inhibiting tumor neoangiogenesis or normalizing the tumor vasculature. Among the most promising therapeutic targets are receptor tyrosine kinases (RTKs), some of which are predominantly expressed on tumor endothelial cells, although they are sometimes also present on tumor cells. The majority of RTK inhibitors investigated over the past two decades competes with ATP at the active site of the kinase and therefore block the phosphorylation of intracellular targets. Some of these drugs have been approved for therapy, whereas others are still in clinical trials. Here, we discuss the scientific basis, current status, problems and future prospects of RTK inhibition in anti-tumor therapy.

Genotype Correlations With Blood Pressure and Efficacy From a Randomized Phase III Trial of Second-Line Axitinib Versus Sorafenib in Metastatic Renal Cell Carcinoma

BACKGROUND

In the phase III axitinib second-line (AXIS) trial, axitinib significantly prolonged progression-free survival (PFS) versus sorafenib in patients with previously treated metastatic renal cell carcinoma (mRCC). Analyses of associations between germline single-nucleotide polymorphisms (SNPs) and outcomes are reported.

PATIENTS AND METHODS

DNA samples from blood were genotyped using TaqMan allelic discrimination. Logistic/Cox regression analyses were used to evaluate association of 15 SNPs in vascular endothelial growth factor (VEGF)-A, VEGF receptor (VEGFR)1, VEGFR2, or hypoxia-inducible factor (HIF)-1α with outcomes for blood pressure (BP; Grade ≥ 3 hypertension, diastolic BP > 90 mm Hg, and increase ≥ 15 mm Hg from baseline) and efficacy (independent review committee-assessed objective response rate and PFS, and overall survival [OS]). Multivariate analyses assessed SNPs and baseline characteristics as potential predictors of PFS and OS.

RESULTS

Genotype data were available for 305 (42.7%) of 714 patients; 159 received axitinib and 146 sorafenib. After Bonferroni adjustment, no SNP was associated with BP outcomes. In axitinib-treated patients, VEGF-A rs699947 (A/A vs. C/C) and rs833061 (C/C vs. T/T) were associated with longer OS (27.0 vs. 13.4 months; hazard ratio [HR], 0.39; Padjusted = .015). In sorafenib-treated patients, VEGFR2 rs2071559 (G/G vs. A/A) was associated with longer OS (26.8 vs. 13.8 months; HR, 0.41; Padjusted = .030). In multivariate analyses, no SNP predicted axitinib efficacy; VEGFR2 rs2071559 predicted PFS (P = .0053) and OS (P = .0027) for sorafenib. Sensitivity/specificity of VEGFR2 rs2071559 for OS was < 80%.

CONCLUSION

No SNP predicted axitinib outcomes. Although VEGFR2 rs2071559 predicted sorafenib efficacy in patients with mRCC, sensitivity/specificity limitations preclude its use for selecting individual patients for sorafenib treatment.

Phase I Study of Axitinib in Combination with Cisplatin and Capecitabine in Patients with Previously Untreated Advanced Gastric Cancer

PURPOSE

This phase I trial evaluated the question of whether the standard starting dose of axitinib could be administered in combination with therapeutic doses of cisplatin/capecitabine in patients with previously untreated advanced gastric cancer, and assessed overall safety, pharmacokinetics, and preliminary antitumor activity of this combination.

MATERIALS AND METHODS

Patients in dose level (DL) 1 received axitinib 5 mg twice a day (days 1 to 21) with cisplatin 80 mg/m(2) (day 1) and capecitabine 1,000 mg/m(2) twice a day (days 1 to 14) in 21-day cycles. Maximum tolerated dose (MTD) was the highest dose at which ≤ 30% of the first 12 patients experienced a dose-limiting toxicity (DLT) during cycle 1. Ten additional patients were enrolled and treated at the MTD in order to obtain additional safety and pharmacokinetic data.

RESULTS

Three DLTs occurred during cycle 1 in three (25%) of the first 12 patients: ruptured abdominal aortic aneurysm, acute renal failure, and > 5 consecutive days of missed axitinib due to thrombocytopenia. DL1 was established as the MTD, since higher DL cohorts were not planned. Common grade 3/4 non-hematologic adverse events in 22 patients treated at DL1 included hypertension (36.4%) and decreased appetite and stomatitis (18.2% each). Cisplatin/capecitabine slightly increased axitinib exposure; axitinib decreased capecitabine and 5-fluorouracil exposure. Eight patients (36.4%) each had partial response or stable disease. Median response duration was 9.1 months; median progression-free survival was 3.8 months.

CONCLUSION

In patients with advanced gastric cancer, standard doses of axitinib plus therapeutic doses of cisplatin and capecitabine could be administered in combination. Adverse events were manageable.

Axitinib increases the infiltration of immune cells and reduces the suppressive capacity of monocytic MDSCs in an intracranial mouse melanoma model

Melanoma patients are at a high risk of developing brain metastases, which are strongly vascularized and therefore have a significant risk of spontaneous bleeding. VEGF not only plays a role in neo-angiogenesis but also in the antitumor immune response. VEGFR-targeted therapy might not only have an impact on the tumor vascularization but also on tumor-infiltrating immune cells. In this study, we investigated the effect of axitinib, a small molecule TKI of VEGFR-1, -2, and -3, on tumor growth and on the composition of tumor-infiltrating immune cells in subcutaneous and intracranial mouse melanoma models. In vivo treatment with axitinib induced a strong inhibition of tumor growth and significantly improved survival in both tumor models. Characterization of the immune cells within the spleen and tumor of tumor-bearing mice respectively showed a significant increase in the number of CD3⁺CD8⁺ T cells and CD11b⁺ cells of axitinib-treated mice. More specifically, we observed a significant increase of intratumoral monocytic myeloid-derived suppressor cells (moMDSCs; CD11b⁺Ly6C^highLy6G^-). Interestingly, in vitro proliferation assays showed that moMDSCs isolated from spleen or tumor of axitinib-treated mice had a reduced suppressive capacity on a per cell basis as compared to those isolated from vehicle-treated mice. Moreover, MDSCs from axitinib-treated animals displayed the capacity to stimulate allogeneic T cells. Thus, treatment with axitinib induces differentiation of moMDSC toward an antigen-presenting phenotype. Based on these observations, we conclude that the impact of axitinib on tumor growth and survival is most likely not restricted to direct anti-angiogenic effects but also involves important effects on tumor immunity.

Pharmacokinetics of single-agent axitinib across multiple solid tumor types

PURPOSE

Axitinib, a potent and selective inhibitor of vascular endothelial growth factor receptors, showed antitumor activity as a single agent against several solid tumor types in Phase II and III trials. This study was conducted to evaluate axitinib pharmacokinetics across a variety of solid tumors.

METHODS

The current study analyzed the pharmacokinetics of axitinib in 110 patients with non-small cell lung cancer (NSCLC), thyroid cancer, or melanoma from three Phase II trials plus 127 healthy volunteers, using nonlinear mixed-effects modeling. Boxplots of maximum observed plasma concentration (C max) and area under the plasma concentration-time curve (AUC) of data from these tumor populations was compared to C max and AUC from the final population pharmacokinetic model developed for metastatic renal cell carcinoma (mRCC) to compare axitinib pharmacokinetics across different tumor types.

RESULTS

Axitinib disposition based on data from 237 subjects was best described using a two-compartment model with first-order absorption and lag time. Population estimates for systemic clearance, central volume of distribution, absorption rate constant, absolute bioavailability, and lag time were 20.1 L/h, 56.2 L, 1.26/h(-1), 0.663, and 0.448 h, respectively. Statistically significant covariates included gender on clearance, and body weight on central volume of distribution. However, predicted changes due to gender and body weight were found not clinically meaningful. The final analysis indicated that the pharmacokinetic model for mRCC was able to successfully describe axitinib pharmacokinetics in patients with NSCLC, thyroid cancer, and melanoma.

CONCLUSION

The pharmacokinetics of axitinib appears to be similar across a variety of tumor types.

Mechanisms of tumour vascularization in cutaneous malignant melanoma: clinical implications

Malignant melanoma represents < 10% of all skin cancers but is responsible for the majority of skin-cancer-related deaths. Metastatic melanoma has historically been considered as one of the most therapeutically challenging malignancies. Fortunately, for the first time after decades of basic research and clinical investigation, new drugs have produced major clinical responses. Angiogenesis has been considered an important target for cancer treatment. Initial efforts have focused primarily on targeting endothelial and tumour-related vascular endothelial growth factor signalling. Here, we review different mechanisms of tumour vascularization described in melanoma and discuss the potential clinical implications.

Axitinib alone or in combination with chemotherapeutic drugs exerts potent antitumor activity against human gastric cancer cells in vitro and in vivo

OBJECTIVE

As the new oral selective VEGFR tyrosine kinase inhibitor, axitinib (AG-013736) exerts powerful antitumor activity in multiple solid tumors, while its' effect was unclear in gastric cancer. We aimed to investigate the antitumor activity of axitinib alone or combined with chemotherapeutic drugs against human gastric cancer cells in vitro and in vivo.

METHODS

The IC50 values of drugs were determined by MTS assay. The median effect of Chou-Talalay was used to assess the synergistic effect of two drugs. Flow cytometry was employed to analyze cell cycle and cell apoptosis. Cell senescence and microvessel density were evaluated by SA-β-gal staining and CD34 staining, respectively. BGC-823-derived xenografts in nude mice were established to investigate the effects of drugs in vivo.

RESULTS

Axitinib alone could inhibit cell proliferation and retard tumor growth through inducing cell cycle arrest at G2/M phase, cell senescence, cell apoptosis, and antiangiogenesis in vitro and in vivo. Axitinib combined with 5-fluorouracil (5-FU) had synergistic inhibitory effect compared to axitinib or 5-FU alone. However, the highest inhibitory effect was found between axitinib and cisplatin (inhibitory ratio >80 % compared to control), which was significantly higher than any single drug (inhibitory ratio for single 5-FU, cisplatin, and axitinib >10, >40, and >40 %, respectively, compared to control) or axitinib combined with 5-FU (inhibitory ratio >50 % compared to control).

CONCLUSION

We highlighted for the first time that axitinib alone or in combination with 5-fluorouracil or cisplatin has potent antitumor activity against human gastric cancer in vitro and in vivo, which provided solid evidence for future clinical trial.

Incidence and risk of hypertension with a novel multi-targeted kinase inhibitor axitinib in cancer patients: a systematic review and meta-analysis

AIMS

To investigate the overall incidence and risk of hypertension in cancer patients who receive axitinib and compare the differences in incidences between axitinib and the other four approved vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitors (TKIs).

METHODS

Several databases were searched, including Pubmed, Embase and Cochrane databases. Eligible studies were phase II and III prospective clinical trials of patients with cancer assigned axitinib at a starting dose of 5 mg orally twice daily with data on hypertension available. Overall incidence rates, relative risk (RR), and 95% confidence intervals (CI) were calculated employing fixed or random effects models depending on the heterogeneity of the included trials.

RESULTS

A total of 1908 patients from 10 clinical trials were included. The overall incidences of all grade and high grade hypertension in cancer patients were 40.1% (95% CI 30.9, 50.2%) and 13.1% (95% CI 6.7, 24%). The use of axitinib was associated with significantly increased risk of all grade (RR 3.00, 95% CI 1.29, 6.97, P = 0.011) and high grade hypertension (RR 1.71, 95% CI 1.21, 2.43, P = 0.003). The risk of axitinib associated all grade and high grade hypertension in renal cell carcinoma (RCC) was significantly higher than that in non-RCC. Additionally, the risk of hypertension with axitinib was substantially higher than other approved VEGFR-TKIs, while the risk of all grade hypertension with axitinib was similar to pazopanib (RR 1.05; 95% CI 0.95-, 1.17, P = 0.34).

CONCLUSIONS

While sharing a similar spectrum of target receptors with other VEGFR-TKIs, axitinib is associated with an unexpectedly high risk of developing hypertension. Close monitoring and appropriate management for hypertension are recommended during the treatment.

Axitinib (AG-013736), an oral specific VEGFR TKI, shows potential therapeutic utility against cholangiocarcinoma

OBJECTIVE

Cholangiocarcinoma is a refractory cancer whose incidence has been increasing worldwide in recent years. Neoangiogenesis plays an important role in the growth of various solid cancers, including cholangiocarcinoma. Vascular endothelial growth factor plays an important role in tumor-induced angiogenesis and its expression is associated with the progression and prognosis of cholangiocarcinoma. This study examined whether axitinib (AG-013736, INLYTA(®)), a potent and selective second-generation inhibitor of vascular endothelial growth factor receptors 1, 2 and 3, could be a potentially useful therapeutic agent for cholangiocarcinoma.

METHODS

We performed expression profiling of angiogenesis-related molecules in eight cholangiocarcinoma cell lines and found that three of them showed high vascular endothelial growth factor expression. Among them, we examined the in vivo anti-tumor effect of axitinib on NCC-BD1 (a gemcitabine-sensitive extra-hepatic cholangiocarcinoma cell line) and TKKK (a gemcitabine-resistant intra-hepatic cholangiocarcinoma cell line) using subcutaneous xenograft models.

RESULTS

Oral administration of axitinib significantly inhibited the growth of TKKK xenografts at a dose of 6 mg kg(-1) day(-1) (P<0.05), and the growth of NCC-BD1 xenografts at 30 mg kg(-1)day(-1) (P<0.05). Treated tumors showed a significant decrease of microvessel density and the tumor cell proliferation index and a mild but significant increase of the apoptotic index in comparison with untreated tumors.

CONCLUSIONS

Our results suggest that axitinib should be a promising therapy for vascular endothelial growth factor-expressing cholangiocarcinoma, irrespective of tumor origin and gemcitabine sensitivity.

Adjuvant bevacizumab in patients with melanoma at high risk of recurrence (AVAST-M): preplanned interim results from a multicentre, open-label, randomised controlled phase 3 study

BACKGROUND

Bevacizumab, a monoclonal antibody that targets VEGF, has shown restricted activity in patients with advanced melanoma. We aimed to assess the role of bevacizumab as adjuvant treatment for patients with resected melanoma at high risk of recurrence. We report results from the preplanned interim analysis.

METHODS

We did a multicentre, open-label, randomised controlled phase 3 trial at 48 centres in the UK between July 18, 2007, and March 29, 2012. Patients aged 16 years or older with American Joint Committee on Cancer stage (AJCC) stage IIB, IIC, and III cutaneous melanoma were randomly allocated (1:1), via a central, computer-based minimisation procedure, to receive intravenous bevacizumab 7.5 mg/kg, every 3 weeks for 1 year, or to observation. Randomisation was stratified by Breslow thickness of the primary tumour, N stage according to AJCC staging criteria, ulceration of the primary tumour, and patient sex. The primary endpoint was overall survival; secondary endpoints included disease-free interval, distant-metastases interval and quality of life. Analysis was by intention-to-treat. This trial is registered as an International Standardised Randomised Controlled Trial, number ISRCTN81261306.

FINDINGS

1343 patients were randomised to either the bevacizumab group (n=671) or the observation group (n=672). Median follow-up was 25 months (IQR 16-37) in the bevacizumab group and 25 months (17-37) in the observation group. At the time of interim analysis, 286 (21%) of 1343 enrolled patients had died: 140 (21%) of 671 patients in the bevacizumab group, and 146 (22%) of 672 patients in the observation group. 134 (96%) of patients in the bevacizumab group died because of melanoma versus 139 (95%) in the observation group. We noted no significant difference in overall survival between treatment groups (hazard ratio [HR] 0.97, 95% CI 0.78-1.22; p=0.76); this finding persisted after adjustment for stratification variables (HR 1.03; 95% CI 0.81-1.29; p=0.83). Median duration of treatment with bevacizumab was 51 weeks (IQR 21-52) and dose intensity was 86% (41-96), showing good tolerability. 180 grade 3 or 4 adverse events were recorded in 101 (15%) of 671 patients in the bevacizumab group, and 36 (5%) of 672 patients in the observation group. Bevacizumab resulted in a higher incidence of grade 3 hypertension than did observation (41 [6%] vs one [<1%]). There was an improvement in disease-free interval for patients in the bevacizumab group compared with those in the observation group (HR 0.83, 95% CI 0.70-0.98, p=0.03), but no significant difference between groups for distant-metastasis-free interval (HR 0.88, 95% CI 0.73-1.06, p=0.18). No significant differences were noted between treatment groups in the standardised area under the curve for any of the quality-of-life scales over 36 months. Three adverse drug reactions were regarded as both serious and unexpected: one patient had optic neuritis after the first bevacizumab infusion, a second patient had persistent erectile dysfunction, and a third patient died of a haemopericardium after receiving two bevacizumab infusions and was later identified to have had significant predisposing cardiovascular risk factors.

INTERPRETATION

Bevacizumab has promising tolerability. Longer follow-up is needed to identify an effect on the primary endpoint of overall survival at 5 years.

Resistance to the tyrosine kinase inhibitor axitinib is associated with increased glucose metabolism in pancreatic adenocarcinoma

Alterations in energy (glucose) metabolism are key events in the development and progression of cancer. In pancreatic adenocarcinoma (PDAC) cells, we investigated changes in glucose metabolism induced by resistance to the receptor tyrosine kinase inhibitor (RTKI) axitinib. Here, we show that human cell lines and mouse PDAC cell lines obtained from the spontaneous pancreatic cancer mouse model (Kras(G12D)Pdx1-cre) were sensitive to axitinib. The anti-proliferative effect was due to a G2/M block resulting in loss of 70-75% cell viability in the most sensitive PDAC cell line. However, a surviving sub-population showed a 2- to 3-fold increase in [C-14]deoxyglucose ([C-14]DG) uptake. This was sustained in axitinib-resistant cell lines, which were derived from parental PDAC. In addition to the axitinib-induced increase in [C-14]DG uptake, we observed a translocation of glucose transporter-1 (Glut-1) transporters from cytosolic pools to the cell surface membrane and a 2-fold increase in glycolysis rates measured by the extracellular acidification rate (ECAR). We demonstrated an axitinib-induced increase in phosphorylated Protein Kinase B (pAkt) and by blocking pAkt with a phosphatidylinositol-3 kinase (PI3K) inhibitor we reversed the Glut-1 translocation and restored sensitivity to axitinib treatment. Combination treatment with both axitinib and Akt inhibitor in parental pancreatic cell line resulted in a decrease in cell viability beyond that conferred by single therapy alone. Our study shows that PDAC resistance to axitinib results in increased glucose metabolism mediated by activated Akt. Combining axitinib and an Akt inhibitor may improve treatment in PDAC.