Clinical Activity and Safety of Cabozantinib for Brain Metastases in Patients With Renal Cell Carcinoma

Therapeutic options for different metastatic sites arising from renal cell carcinoma: A review

Renal cell carcinoma (RCC) stands among the top 10 malignant neoplasms with the highest fatality rates. It exhibits pronounced heterogeneity and robust metastatic behavior. Patients with RCC may present with solitary or multiple metastatic lesions at various anatomical sites, and their prognoses are contingent upon the site of metastasis. When deliberating the optimal therapeutic approach for a patient, thorough evaluation of significant risk factors such as the feasibility of complete resection, the presence of oligometastases, and the patient's functional and physical condition is imperative. Recognizing the nuanced differences in RCC metastasis to distinct organs proves advantageous in contemplating potential treatment modalities aimed at optimizing survival outcomes. Moreover, discerning the metastatic site holds promise for enhancing risk stratification in individuals with metastatic RCC. This review summarizes the recent data pertaining to the current status of different RCC metastatic sites and elucidates their role in informing clinical management strategies across diverse metastatic locales of RCC.

Metastatic Kidney Cancer: Does the Location of the Metastases Matter? Moving towards Personalized Therapy for Metastatic Renal Cell Carcinoma

The management of renal cell carcinoma (RCC) has been revolutionized over the past two decades with several practice-changing treatments. Treatment for RCC often requires a multimodal approach: Local treatment, such as surgery or ablation, is typically recommended for patients with localized tumors, while stage IV cancers often require both local and systemic therapy. The treatment of advanced RCC heavily relies on immunotherapy and targeted therapy, which are highly contingent upon histological subtypes. Despite years of research on biomarkers for RCC, the standard of care is to choose systemic therapy based on the risk profile according to the International Metastatic RCC Database Consortium and Memorial Sloan Kettering Cancer Centre models. However, many questions still need to be answered. Should we consider metastatic sites when deciding on treatment options for metastatic RCC? How do we choose between dual immunotherapy and combinations of immunotherapy and tyrosine kinase inhibitors? This review article aims to answer these unresolved questions surrounding the concept of personalized medicine.

Fatal tumoral hemorrhage from brain metastases of renal cell carcinoma after stereotactic radiotherapy and immune checkpoint inhibitor and vascular endothelial growth factor-targeted therapy combinations

Introduction

Brain metastasis in renal cell carcinoma, which is reported in 10% of cases, leads to significant morbidity and mortality. Establishment of appropriate and safe treatment for brain metastasis renal cell carcinoma remains a pressing need.

Case presentation

A 56-year-old female patient, presenting with anorexia, headache, and occipital swelling, was subsequently diagnosed with clear cell renal cell carcinoma with multiple metastases, including intracranial and epicranial tumors. The patient initially underwent stereotactic radiotherapy for metastatic brain tumors and then received combination therapy with pembrolizumab and lenvatinib. However, after 30 days of treatment, the patient experienced a sudden loss of consciousness due to massive multifocal intracranial hemorrhage, leading to her death the following day.

Conclusion

Although fatal tumoral hemorrhage during combined stereotactic radiotherapy and immune checkpoint inhibitor/VEGF-targeted therapy for patients with brain metastasis renal cell carcinoma is an extremely rare complication, it should always be considered a possibility.

Special populations in metastatic renal cell carcinoma

PURPOSE OF REVIEW

This review focuses on special populations poorly represented in current evidence-based practice for metastatic renal cell carcinoma (mRCC). This includes the elderly and frail, patients on immunosuppression or with autoimmune diseases, patients with brain, liver, and/or bone metastases, and RCC with sarcomatoid features.

RECENT FINDINGS

Certain populations are poorly represented in current trials for mRCC. Patients with central nervous system (CNS) metastases are often excluded from first-line therapy trials. Modern doublet systemic therapy appears to benefit patients with bone or liver metastases, but data supporting this conclusion is not robust. Post-hoc analyses on patients with sarcomatoid differentiation have shown improved response to modern doublet therapy over historical treatments. The elderly are underrepresented in current clinical trials, and most trials exclude all but high-performing (nonfrail) patients, though true frailty is likely poorly captured using the current widely adopted indices. It is difficult to make conclusions about the efficacy of modern therapy in these populations from subgroup analyses. Data from trials on other malignancies in patients with autoimmune diseases or solid organ transplant recipients on immunosuppression suggest that immune checkpoint inhibitors (ICIs) may still have benefit, though at the risk of disease flare or organ rejection. The efficacy of ICIs has not been demonstrated specifically for RCC in this group of patients.

SUMMARY

The elderly, frail, and immunosuppressed, those with tumors having aggressive histologic features, and patients with brain, bone, and/or liver metastases represent the populations least understood in the modern era of RCC treatment.

Advanced renal cell carcinoma management: the Latin American Cooperative Oncology Group (LACOG) and the Latin American Renal Cancer Group (LARCG) consensus update

PURPOSE

Renal cell carcinoma is an aggressive disease with a high mortality rate. Management has drastically changed with the new era of immunotherapy, and novel strategies are being developed; however, identifying systemic treatments is still challenging. This paper presents an update of the expert panel consensus from the Latin American Cooperative Oncology Group and the Latin American Renal Cancer Group on advanced renal cell carcinoma management in Brazil.

METHODS

A panel of 34 oncologists and experts in renal cell carcinoma discussed and voted on the best options for managing advanced disease in Brazil, including systemic treatment of early and metastatic renal cell carcinoma as well as nonclear cell tumours. The results were compared with the literature and graded according to the level of evidence.

RESULTS

Adjuvant treatments benefit patients with a high risk of recurrence after surgery, and the agents used are pembrolizumab and sunitinib, with a preference for pembrolizumab. Neoadjuvant treatment is exceptional, even in initially unresectable cases. First-line treatment is mainly based on tyrosine kinase inhibitors (TKIs) and immune checkpoint inhibitors (ICIs); the choice of treatment is based on the International Metastatic Database Consortium (IMCD) risk score. Patients at favourable risk receive ICIs in combination with TKIs. Patients classified as intermediate or poor risk receive ICIs, without preference for ICI + ICIs or ICI + TKIs. Data on nonclear cell renal cancer treatment are limited. Active surveillance has a place in treating favourable-risk patients. Either denosumab or zoledronic acid can be used for treating metastatic bone disease.

CONCLUSION

Immunotherapy and targeted therapy are the standards of care for advanced disease. The utilization and sequencing of these therapeutic agents hinge upon individual risk scores and responses to previous treatments. This consensus reflects a commitment to informed decision-making, drawn from professional expertise and evidence in the medical literature.

Treatment of metastatic TFE3 microphthalmia transcription factor translocation renal cell carcinoma: a case report

Background

Microphthalmia-associated transcription factor/transcription factor E (MiTF/TFE) translocation renal cell carcinoma (RCC) is a rare type of non-clear cell RCC (nccRCC), which is more common in females. Currently, there is no standardized treatment for advanced metastatic microphthalmia translocation RCC (MiT-RCC). The main treatment modalities include surgery, chemotherapy, immunotherapy, anti-vascular endothelial growth factor or vascular endothelial growth factor receptor (VEGFR) inhibitors, mammalian target of rapamycin (mTOR) inhibitors, and targeted therapy against the mesenchymal-epithelial transition (MET) factor signaling pathway.

Case Description

We present the case of an 8-year-old male patient with hematuria and paroxysmal urinary pain. Based on tumor genetic testing results and targeted drug matching analysis, the patient underwent tumor biopsy, tumor radical surgery with vascular osteotomy, and cervicothoracic lymph node dissection. The patient was then treated with a combination of immunotherapy [sintilimab, a drug directed against programmed cell death receptor-1 (PD-1)] and VEGFR tyrosine kinase inhibitor (TKI) (from pazopanib to sunitinib). Throughout the 10 cycles of conventional chemotherapy (seven courses of sintilimab since the start of the third chemotherapy treatment), the patient's condition remained stable, with no tumor recurrence at the primary site. However, in the later stages, the patient developed a large amount of ascites, and the family requested discontinuation of treatment, ultimately leading to the patient's death.

Conclusions

In this case report, we summarize the therapeutic strategy of a young patient with metastatic transcription factor E3 (TFE3) MiT-RCC. For this disease, early immunotherapy and the use of precision-targeted drugs may have a favorable impact on the survival prognosis of the patient but may still be of less benefit in children with advanced multiple metastases. Therefore, further research on tumor driver genes, among other treatment components, is urgently needed to improve precision therapy.

Cabozantinib in the Routine Management of Renal Cell Carcinoma: A Systematic Literature Review of Real-World Evidence

Real-world cabozantinib use has increased since its approval to treat patients with advanced renal cell carcinoma (RCC) in 2016. We reviewed cabozantinib use in real-world clinical practice and compared outcomes with pivotal cabozantinib randomized control trials (RCTs). This PRISMA-standard systematic literature review evaluated real-world effectiveness and tolerability of cabozantinib in patients with RCC (PROSPERO registration: CRD42021245854). Systematic MEDLINE, Embase, and Cochrane database searches were conducted on November 2, 2022. Eligible publications included ≥ 20 patients with RCC receiving cabozantinib. After double-screening for eligibility, standardized data were abstracted, qualitatively summarized, and assessed for risk of bias using the Newcastle-Ottawa Scale. Of 353 screened publications, 41 were included, representing approximately 11,000 real-world patients. Most publications reported cabozantinib monotherapy cohort studies (40/41) of retrospective (39/41) and multicenter (32/41) design; most included patients from North America and/or Europe (30/41). Baseline characteristics were demographically similar between real-world and pivotal RCT populations, but real-world populations showed greater variation in prevalence of prior nephrectomy, multiple-site/brain metastasis, and nonclear-cell RCC histology. Cabozantinib activity was reported across real-world treatment lines and tumor types. Overall survival, progression-free survival, and objective response rate values from pivotal RCTs were within the ranges reported for equivalent outcomes across real-world studies. Common real-world grade ≥ 3 adverse events were consistent with those in pivotal RCTs (fatigue, palmar-plantar erythrodysesthesia syndrome, diarrhea, hypertension), but less frequent. No new tolerability concerns were identified. Real-world RCC survival outcomes for cabozantinib monotherapy were broadly consistent with pivotal RCTs, despite greater heterogeneity in real-world populations.

Incorporating Stereotactic Ablative Radiotherapy into the Multidisciplinary Management of Renal Cell Carcinoma

Stereotactic ablative radiotherapy (SABR) has challenged the conventional wisdom surrounding the radioresistance of renal cell carcinoma (RCC). In the past decade, there has been a significant accumulation of clinical data to support the safety and efficacy of SABR in RCC. Herein, we review the use of SABR across the spectrum of RCC. We performed an online search of the Pubmed database from January 1990 through April 2023. Studies of SABR/stereotactic radiosurgery targeting primary, extracranial, and intracranial metastatic RCC were included. For SABR in non-metastatic RCC, this includes its use in small renal masses, larger renal masses, and inferior vena cava tumor thrombi. In the metastatic setting, SABR can be used at diagnosis, for oligometastatic and oligoprogressive disease, and for symptomatic reasons. Notably, SABR can be used for both the primary renal tumor and metastasis-directed therapy. Management of RCC is evolving rapidly, and the role that SABR will have in this landscape is being assessed in a number of ongoing prospective clinical trials. The objective of this narrative review is to summarize the evidence corroborating the use of SABR in RCC.

Efficacy and safety of second-line cabozantinib after immuno-oncology combination therapy for advanced renal cell carcinoma: Japanese multicenter retrospective study

Immuno-oncology (IO) combination therapy is utilized as a first-line systemic treatment for advanced renal cell carcinoma. However, evidence supporting the use of cabozantinib after IO combination therapy is lacking. We retrospectively analyzed patients who received second-line cabozantinib after IO combination therapy using the Japanese Urological Oncology Group (JUOG) database. In total, 254 patients were enrolled in the JUOG global study, and 118 patients who received second-line cabozantinib comprised the study cohort. The objective response rate, disease control rate, second-line cabozantinib progression-free survival (PFS), and overall survival from second-line for overall were 32%, 75%, 10.5 months, and not reached, respectively, for first-line IO-IO therapy were 37%, 77%, 11.1 months, and not reached, respectively, versus 24%, 71%, 8.3 months, and not reached, respectively, for first-line IO-tyrosine kinase inhibitor therapy. In univariate and multivariate analyses, discontinuation of first-line treatment because of progressive disease and liver metastasis were independent risk factors for PFS. All-grade adverse events occurred in 72% of patients, and grade 3 or higher adverse events occurred in 28% of patients. Second line-cabozantinib after first-line IO combination therapy for advanced renal cell carcinoma was expected to be effective after either IO-IO or IO-TKI treatment and feasible in real-world practice.

Management of Brain Metastases in Metastatic Renal Cell Carcinoma

The development of brain metastases is a poor prognostic indicator in renal cell carcinoma. Regular imaging and clinical examinations are necessary to monitor the brain before or during systemic therapy. Central nervous system-targeted radiation therapy, including stereotactic radiosurgery, whole-brain radiation therapy, and surgical resection, is a standard treatment option. Clinical trials are currently investigating the role of targeted therapy and immune checkpoint inhibitor combinations in treating brain metastases and decreasing intracranial disease progression.

An Overview of Systemic Targeted Therapy in Renal Cell Carcinoma, with a Focus on Metastatic Renal Cell Carcinoma and Brain Metastases

The most commonly diagnosed malignancy of the urinary system is represented by renal cell carcinoma. Various subvariants of RCC were described, with a clear-cell type prevailing in about 85% of all RCC tumors. Patients with metastases from renal cell carcinoma did not have many effective therapies until the end of the 1980s, as long as hormonal therapy and chemotherapy were the only options available. The outcomes were unsatisfactory due to the poor effectiveness of the available therapeutic options, but then interferon-alpha and interleukin-2 showed treatment effectiveness, providing benefits but only for less than half of the patients. However, it was not until 2004 that targeted therapies emerged, prolonging the survival rate. Currently, new technologies and strategies are being developed to improve the actual efficacy of available treatments and their prognostic aspects. This article summarizes the mechanisms of action, importance, benefits, adverse events of special interest, and efficacy of immunotherapy in metastatic renal cell carcinoma, with a focus on brain metastases.

Profiling tyrosine kinase inhibitors as AD therapeutics in a mouse model of AD

Alzheimer's disease (AD) is a neurodegenerative disease characterized by Aβ deposition, tauopathy, neuroinflammation, and impaired cognition. The recent identification of associations between protein kinases and AD pathology has spurred interest in tyrosine kinase inhibitors (TKIs) as potential strategic therapeutic agents for AD. In the present study, we investigated whether the TKIs ibrutinib, PD180970, and cabozantinib, which have different on-targets, selectively regulate AD pathology in 3.5- to 4-month-old 5xFAD mice (a model of the early phase of AD). Ibrutinib (10 mg/kg, i.p.) effectively reduced amyloid-β (Aβ) plaque number, tau hyperphosphorylation and neuroinflammation in 5xFAD mice. Surprisingly, PD180970 (10 mg/kg, i.p.) did not alter Aβ plaque number or neuroinflammatory responses and exacerbated tau hyperphosphorylation in 5xFAD mice. Cabozantinib (10 mg/kg, i.p.) had no effect on amyloidopathy but partially relieved tau hyperphosphorylation and astrogliosis. Taken together, our results suggest that not all TKIs have therapeutic effects on AD pathology in a mouse model of AD. Consequently, optimization of drug dosage, injection periods and administration routes should be considered when repurposing TKIs as novel AD therapeutics.

Immune dysfunction revealed by digital spatial profiling of immuno-oncology markers in progressive stages of renal cell carcinoma and in brain metastases

BACKGROUND

The tumor microenvironment (TME) contributes to cancer progression and treatment response to therapy, including in renal cell carcinoma (RCC). Prior profiling studies, including single-cell transcriptomics, often involve limited sample sizes and lack spatial orientation. The TME of RCC brain metastases, a major cause of morbidity, also remains largely uncharacterized.

METHODS

We performed digital spatial profiling on the NanoString GeoMx platform using 52 validated immuno-oncology markers on RCC tissue microarrays representing progressive stages of RCC, including brain metastases. We profiled 76 primary tumors, 27 adjacent histologically normal kidney samples, and 86 metastases, including 24 brain metastases.

RESULTS

We observed lower immune checkpoint (TIM-3 and CTLA-4), cytolytic (GZMA and GZMB), and T cell activation (CD25) protein expression in metastases compared with primary tumors in two separate cohorts. We also identified changes in macrophages in metastases, with brain metastases-susceptible patients showing less M1-like, inflammatory macrophage markers (HLA-DR and CD127) in metastatic samples. A comparison of brain metastases to extracranial metastases revealed higher expression of the anti-apoptotic, BCL-2-family protein BCL-XL and lower expression of the innate immune activator STING in brain metastases. Lower TIM-3 and CD40 in the TME of brain metastases appear to be associated with longer survival, a finding that requires further validation.

CONCLUSIONS

Compared with primary tumors, RCC metastases, including brain metastases, express lower levels of numerous markers of immune activation and current or investigational therapeutic targets. Our findings may have important implications for designing future biomarker and treatment studies and may aid in development of brain metastases-specific therapies.

Exceptional response to lorlatinib and cabozantinib in ROS1-rearranged NSCLC with acquired F2004V and L2086F resistance

Patients with ROS1-rearranged NSCLC demonstrate excellent disease control with ROS1-targeted therapy, but acquired resistance is inevitable. Of particular interest is the ROS1 L2086F kinase domain mutation which is refractory to all currently available ROS1 TKIs apart from cabozantinib. We present a case of a patient with metastatic ROS1-rearranged NSCLC with dual ROS1 F2004V and L2086F resistance mutations who radiographically responded to the combination of lorlatinib and cabozantinib in a patient with metastatic NSCLC. Furthermore, the patient experienced exceptional clinical improvement and tolerance with the combined use of lorlatinib and cabozantinib. This case builds the case for cabozantinib as an agent to overcome ROS1 L2086F resistance. It also highlights the efficacy and safety of using combination of ROS1 TKIs to overcome complex resistance patterns.

Building Team Medicine in the Management of CNS Metastases

CNS metastases are often terminal for cancer patients and occur at an approximately 10-fold higher rate than primary CNS tumors. The incidence of these tumors is approximately 70,000-400,000 cases annually in the US. Advances that have occurred over the past two decades have led to more personalized treatment approaches. Newer surgical and radiation techniques, as well as targeted and immune therapies, have enanled patient to live longer, thus increasing the risk for the development of CNS, brain, and leptomeningeal metastases (BM and LM). Patients who develop CNS metastases have often been heavily treated, and options for future treatment could best be addressed by multidisciplinary teams. Studies have indicated that patients with brain metastases have improved survival outcomes when cared for in high-volume academic institutions using multidisciplinary teams. This manuscript discusses a multidisciplinary approach for both parenchymal brain metastases as well as leptomeningeal metastases implemented in three academic institutions. Additionally, with the increasing development of healthcare systems, we discuss optimizing the management of CNS metastases across healthcare systems and integrating basic and translational science into our clinical care to further improve outcomes. This paper summarizes the existing therapeutic approaches to the treatment of BM and LM and discusses novel and emerging approaches to optimizing access to neuro-oncologic care while simultaneously integrating multidisciplinary teams in the care of patients with BM and LM.

Effectiveness of immune checkpoint inhibitors in combination with stereotactic radiosurgery for patients with brain metastases from renal cell carcinoma: inverse probability of treatment weighting using propensity scores

OBJECTIVE

Stereotactic radiosurgery (SRS) is the mainstay for treating brain metastases (BMs) from renal cell carcinoma (RCC). In recent years, immune checkpoint inhibitors (ICIs) have been applied to metastatic RCC and have contributed to improved outcomes. The authors investigated whether SRS with concurrent ICIs for RCC BM prolongs overall survival (OS) and improves intracranial disease control and whether there are any safety concerns.

METHODS

Patients who underwent SRS for RCC BMs at the authors' institution between January 2010 and January 2021 were included. Concurrent use of ICIs was defined as no more than 3 months between SRS and ICI administration. The time-to-event analysis of OS and intracranial progression-free survival (IC-PFS) between the groups with and without ICIs (ICI+SRS and SRS, respectively) was performed using inverse probability of treatment weighting (IPTW) based on propensity scores (PSs) to control for selection bias. Four baseline covariates (Karnofsky Performance Scale score, extracranial metastases, hemoglobin, and number of BMs) were selected to calculate PSs.

RESULTS

In total, 57 patients with 147 RCC BMs were eligible. The median OS for all patients was 9.1 months (95% CI 6.0-18.9 months), and the median IC-PFS was 4.4 months (95% CI 3.1-6.8 months). Twelve patients (21%) received concurrent ICIs. The IPTW-adjusted 1-year OS rates in the ICI+SRS and SRS groups were 66% and 38%, respectively (HR 0.30, 95% C 0.13-0.69; p = 0.005), and the IPTW-adjusted 1-year IC-PFS rates were 52% and 16%, respectively (HR 0.30, 95% CI 0.14-0.62; p = 0.001). Severe tumor hemorrhage (Common Terminology Criteria for Adverse Events [CTCAE] grade 4 or 5) occurred immediately after SRS in 2 patients in the SRS group. CTCAE grade 2 or 3 toxicity was observed in 2 patients in the ICI+SRS group and 5 patients in the SRS group.

CONCLUSIONS

Although the patient number was small and the analysis preliminary, the present study found that SRS with concurrent ICIs for RCC BM patients prolonged survival and provided durable intracranial disease control, with no apparent increase in treatment-related adverse events.

Triplet Strategies in Metastatic Clear Cell Renal Cell Carcinoma: A Worthy Option in the First-Line Setting?

Significant strides have been made in the frontline treatment of patients with advanced clear cell renal cell carcinoma (ccRCC). There are multiple standard-of-care doublet regimens consisting of either the combined dual immune checkpoint inhibitors, ipilimumab and nivolumab, or combinations of a vascular endothelial growth factor receptor tyrosine kinase inhibitor and an immune checkpoint inhibitor. Currently, there is an emergence of clinical trials examining triplet combinations. In COSMIC-313, a randomized phase III trial for patients with untreated advanced ccRCC, the triplet combination of ipilimumab, nivolumab, and cabozantinib was compared with a contemporary control arm of ipilimumab and nivolumab. While patients receiving the triplet regimen demonstrated improved progression-free survival, these patients also experienced greater toxicity and the overall survival data are still maturing. In this article, we discuss the role of doublet therapy as standard of care, the current data available for the promise of triplet therapy, the rationale to continue pursuing trials with triplet combinations, and factors for clinicians and patients to consider when choosing among frontline treatments. We present ongoing trials with an adaptive design that may serve as alternative methods for escalating from doublet to triplet regimens in the frontline setting and explore clinical factors and emerging predictive biomarkers (both baseline and dynamic) that may guide future trial design and frontline treatment for patients with advanced ccRCC.

Impressive reduction of brain metastasis radionecrosis after cabozantinib therapy in metastatic renal carcinoma: A case report and review of the literature

Introduction

Radionecrosis is a consequence of SRS (stereotactic radiosurgery) for brain metastases in 34% of cases, and if symptomatic (8%-16%), it requires therapy with corticosteroids and bevacizumab and, less frequently, surgery. Oncological indications are increasing and appropriate stereotactic adapted LINACs (linear accelerators) are becoming more widely available worldwide. Efforts are being made to treat brain radionecrosis in order to relieve symptoms and spare the use of active therapies.

Case presentation

Herein, we describe a 65-year-old female patient presenting with brain radionecrosis 6 months after stereotactic radiotherapy for two brain metastatic lesions. Being symptomatic with headache and slow cognitive-motor function, the patient received corticosteroids. Because of later lung progression, the patient took cabozantinib. An impressive reduction of the two brain radionecrosis areas was seen at the brain MRI 2 months after the initiation of the angiogenic drug.

Discussion

The high incidence of radionecrosis (2/2 treated lesions) can be interpreted by the combination of SRS and previous ipilimumab that is associated with increased risk of radionecrosis. The molecular mechanisms of brain radionecrosis, and its exact duration in time, are poorly understood. We hypothesize that the antiangiogenic effect of cabozantinib may have had a strong effect in reducing brain radionecrosis areas.

Conclusion

In this clinical case, cabozantinib is associated with a fast and significant volume reduction of brain radionecrosis appearing after SRS and concomitant immunotherapy. This drug seems to show, like bevacizumab, clinical implications not only for its efficacy in systemic disease control but also in reducing brain radionecrosis. More research is needed to evaluate all molecular mechanisms of brain radionecrosis and their interaction with systemic therapies like third-generation TKIs.

Analysis of Anti-Angiogenesis-Related Adverse Events Associated with Vascular Endothelial Growth Factor Receptor-Tyrosine Kinase Inhibitors (VEGFR-TKIs) in Patients with Metastatic Renal Cell Carcinoma

BACKGROUND

Limited studies have evaluated anti-angiogenesis-related adverse events involving oral vascular endothelial growth factor receptor-tyrosine kinase inhibitors (VEGFR-TKIs) in metastatic renal cell carcinoma using real-world data.

OBJECTIVE

This study aimed to investigate the incidence, patterns, and impact on the dose intensity of anti-angiogenesis-related adverse events associated with the use of VEGFR-TKIs in patients with metastatic renal cell carcinoma using real-world data.

METHODS

This cross-sectional study included patients with a diagnosis of metastatic renal cell carcinoma who received axitinib, cabozantinib, pazopanib, sorafenib, and sunitinib at a tertiary hospital in South Korea. We categorized the patients into those who had not previously received a VEGFR-TKI (VEGFR-TKI-naive) and those who had previously received a VEGFR-TKI (VEGFR-TKI-experienced). Anti-angiogenesis-related adverse events were defined as hypertension, proteinuria, bleeding, thrombosis, hypothyroidism, and left ventricular dysfunction, which were rated "possible" or higher based on a causality assessment scale.

RESULTS

Among a total of 988 patients, 674 patients were VEGFR-TKI-naïve and 314 patients were VEGFR-TKI-experienced. Anti-angiogenesis-related adverse events of any grade and severe adverse events occurred in 65.1 and 34.6% of VEGFR-TKI-naïve patients and 54.8 and 36.0% of VEGFR-TKI-experienced patients, respectively. Regardless of treatment history, the most common adverse event was hypertension, with 48.6% in VEGFR-TKI-naïve patients and 35.0% in VEGFR-TKI-experienced patients. For VEGFR-TKI-experienced patients, the overall rate of anti-angiogenesis-related adverse events for sorafenib (24.3%) was lower than that for other VEGFR-TKIs (p < 0.05). Patients experiencing anti-angiogenesis-related adverse events were 1.6 times more likely to receive a low relative dose intensity.

CONCLUSIONS

More than half and more than one-third of patients with renal cell carcinoma receiving VEGFR-TKIs experienced any and severe anti-angiogenesis-related adverse events, respectively. The relative dose intensity of VEGFR-TKI treatment was associated with anti-angiogenesis-related adverse events.

Combinations of Anti-Angiogenic Agents and Immune Checkpoint Inhibitors in Renal Cell Carcinoma: Best Option?

Over the past decade, major advances have been made in the treatment of advanced and metastatic renal cell carcinomas, specifically clear cell carcinomas. For many years the optimal approach was sequential; thus, monotherapies [principally tyrosine kinase inhibitors (TKIs)] targeting angiogenesis until toxicity or progressive disease developed. The rationale was the common mechanisms of action of the targeting agents and avoidance of the risk of overlapping toxicities. Immune checkpoint inhibitors (ICIs) are effective monotherapies, and combinations thereof with anti-angiogenic agents were thus later considered. Synergistic interactions were reported in vitro. Clinical efficacy was evident in three pivotal phase III trials with axitinib-pembrolizumab, cabozantinib-nivolumab, and lenvatinib-pembrolizumab combinations. Two other combinations showed interesting results but did not improve overall survival. However, the data aided our understanding of the new therapeutic approaches. A combination of the ICIs nivolumab and ipilimumab was the first to evidence better progression-free and overall survival compared to sunitinib in patients with intermediate or unfavourable prognoses as evaluated by the International mRCC Database Consortium (IMDC). Here we focus on the TKI-ICI combinations, emphasising the rationale of their use and the clinical results. To date, no biomarker facilitating the selection of an optimal treatment by disease and patient status has been reported.

Clinical and genomic features in patients with second primary glioblastoma following first primary renal cell carcinoma

PURPOSE

To explore the potential pathogenesis and clinical features of second primary glioblastoma (spGBM) following first primary renal cell carcinoma (fpRCC).

METHODS

Patients with spGBM after fpRCC were enrolled from our institution and the SEER dataset. Sanger sequencing, whole genome sequencing, and immunehistochemistry were used to detect molecular biomarkers.

RESULTS

Four and 122 cases from our institution and the SEER dataset, respectively, were collected with an overall median age of 69 years at spGBM diagnosis following fpRCC. The median interval time between fpRCC and spGBM was 50.7 months and 4 years, for the four and 122 cases respectively. The median overall survival time was 11.2 and 6.0 months for the two datasets. In addition, spGBM patients of younger age (< 75 years) or shorter interval time (< 1 year) had favorable prognosis (p = 0.081 and 0.05, respectively). Moreover, the spGBM cases were molecularly classified as TERT only paired with TP53 mutation, PIK3CA mutation, EGFR alteration, low tumor mutation burden, and stable microsatellite status.

CONCLUSIONS

This is the first study to investigate the pathogenesis and clinical features of spGBM following spRCC. We found that spGBMs are old-age related, highly malignant, and have short survival time. Moreover, they might be misdiagnosed and treated as brain metastases from RCC. Thus, the incidence of spGBMs after fpRCC is underestimated. Further studies are needed to investigate the underlying molecular mechanisms and clinical biomarkers for the development of spGBM following fpRCC.

Contemplation of the Effect of Nivolumab Plus Cabosantinib Therapy on Cerebral Hemorrhage in Patients with Brain Metastasis of Renal Cell Carcinoma: A Case Report

Although the response to combination therapy has been reported in patients with brain metastases from advanced renal cancer, treatment-related cerebral hemorrhage has not been adequately studied. The CheckMate 9ER clinical trial of nivolumab and cabozantinib excluded patients with brain metastases. Therefore, the associated treatment outcomes in these patients with brain metastases are unclear. Herein, we report a case of bleeding from brain metastases in a patient with advanced renal cancer after gamma knife combination therapy with nivolumab and cabozantinib. Fortunately, the cerebral hemorrhage of the patient was alleviated by conservative treatment. Despite treatment interruption, the metastatic lesions reduced in size, and treatment was gradually resumed. In this case study, we report the risk of cerebral hemorrhage in combination therapy for brain metastasis cases, how to manage hemorrhage cases, and their prognosis.

Less is More? First Impressions From COSMIC-313

The COSMIC-313 phase 3 randomized controlled trial tested the triplet combination of cabozantinib with nivolumab and ipilimumab in comparison with nivolumab plus ipilimumab control as fist-line systemic therapy in metastatic clear cell renal cell carcinoma. The first results presented at the 2022 European Society of Medical Oncology Congress are a milestone for the renal cell carcinoma field because they signal the advent of triplet combinations as potential treatment options for our patients. The present commentary highlights some considerations and potential next steps based on these first impressions.

Outcomes and prognostic factors in metastatic renal cell carcinoma patients with brain metastases

BACKGROUND

To evaluate the outcomes and prognostic factors in patients with brain metastatic renal cell carcinoma (bmRCC).

METHODS

The data of 322 patients with metastatic renal cell carcinoma, taken between 2012 and 2020, were retrospectively reviewed. Overall survival (OS) and prognostic factors were evaluated with Kaplan-Meier analysis and Cox regression analysis.

RESULTS

Forty (12.4%) of the patients had bmRCC. Seventeen (42.5%) of the patients were de novo metastatic, and nine (22.5%) of the patients had brain metastases at presentation. Twenty-four (60%) patients previously had received various therapies (tyrosine kinase inhibitor or checkpoint inhibitors). After brain metastases developed, 35 (87.5%) of the patients received brain radiotherapy (whole-brain radiotherapy or stereotactic radiosurgery), and twenty-five (62.5%) patients received different systemic therapies. Nine patients received sunitinib, nine received pazopanib, five received nivolumab, and two received axitinib. The median OS was 8.8 months (range: 2.9-14.6) for all patients with bmRCC. In univariate analysis, the number of brain metastasis (P = 0.35), the site of brain metastasis (left, right or bilateral) (P = 0.79), the largest size of brain metastasis (P = 0.45), the number of extracranial metastatic sites (P = 0.81), de novo metastatic disease (P = 0.17), primary tumor site (left or right) (P = 0.90), and tumor grade (P = 0.09) were not statistically significant factors on OS. However, age (P = 0.02), a history of nephrectomy (P < 0.001), receiving brain radiotherapy (P = 0.005), and type of systemic treatment (P = 0.04) were statistically significant. Only, the effect of brain radiotherapy on OS (P = 0.01) was confirmed in multivariate analysis.

CONCLUSIONS

In this study, we observed that the prognosis of patients with bmRCC was poor. Despite a small number of patients, we detected that the effect of tyrosine kinase inhibitors and nivolumab was comparable, and receiving brain radiotherapy was a prognostic factor for OS.

VEGFR-TKI treatment for radiation-induced brain injury after gamma knife radiosurgery for brain metastases from renal cell carcinomas

OBJECTIVE

Antiangiogenic vascular endothelial growth factor receptor tyrosine kinase inhibitors play an essential role in systemic therapy for renal cell carcinoma. Given the anti-edematous effect of bevacizumab, an antiangiogenic antibody targeting vascular endothelial growth factor, vascular endothelial growth factor receptor tyrosine kinase inhibitors should exert therapeutic effects on radiation-induced brain injury after stereotactic radiosurgery. This preliminary study aimed to investigate the therapeutic effect of vascular endothelial growth factor receptor tyrosine kinase inhibitor against radiation-induced brain injury.

METHODS

Magnetic resonance images for six patients treated with vascular endothelial growth factor receptor tyrosine kinase inhibitors who were diagnosed with radiation-induced brain injury following gamma knife radiosurgery were retrospectively reviewed.

RESULTS

The median brain edema volume and tumour mass volume in the pre-tyrosine kinase inhibitor period were 57.6 mL (range: 39.4-188.2) and 3.2 mL (range: 1.0-4.6), respectively. Axitinib, pazopanib (followed by cabozantinib) and sunitinib were administered in four, one and one cases, respectively. The median brain edema volume and tumour mass volume in the post-tyrosine kinase inhibitor period were 4.8 mL (range: 1.5-27.8) and 1.6 mL (range: 0.4-3.6), respectively. The median rates of reduction in brain edema volume and tumour mass volume were 90.8% (range: 51.9-97.6%) and 57.2% (range: 20.0-68.6%), respectively. The post-tyrosine kinase inhibitor values for brain edema volume (P = 0.027) and tumour mass volume (P = 0.008) were significantly lower than the pre-tyrosine kinase inhibitor values. Changes in volume were correlated with tyrosine kinase inhibitor use.

CONCLUSION

This study is the first to demonstrate the therapeutic effects of vascular endothelial growth factor receptor tyrosine kinase inhibitors on radiation-induced brain injury in patients with brain metastases from renal cell carcinoma treated via gamma knife radiosurgery.

Determining Front-Line Therapeutic Strategy for Metastatic Clear Cell Renal Cell Carcinoma

The therapeutic landscape for metastatic renal cell carcinoma has rapidly evolved over the years, and we are now in an era of combination therapy strategies employing immune checkpoint blockade and anti-angiogenesis targeted therapy. Since 2018, we have gained regulatory approval for four distinct combination therapies, all with survival benefits, and with guideline recommendation for use in the front-line setting. As such, treatment selection has become increasingly complex with a myriad of treatment choices but little high-level head-to-head data to guide treatment selection. Heterogeneity in tumor biology further complicates treatment selection as tumors vary in behavior and treatment responsiveness. Ongoing development of biomarkers will certainly assist in this setting, and validation of predictive markers represents an unmet need. In their absence, we highlight features of disease and nuances to datasets from landmark prospective clinical trials to help inform treatment selection. There is growing evidence to support deferring upfront systemic therapy in some patients, with opportunities for active surveillance or metastasis-directed therapy. In others, upfront systemic therapy is warranted and necessitates thoughtful consideration of multiple clinicopathologic parameters to inform optimal patient-centered decision making.

An interdisciplinary consensus on the management of brain metastases in patients with renal cell carcinoma

Brain metastases are a challenging manifestation of renal cell carcinoma. We have a limited understanding of brain metastasis tumor and immune biology, drivers of resistance to systemic treatment, and their overall poor prognosis. Current data support a multimodal treatment strategy with radiation treatment and/or surgery. Nonetheless, the optimal approach for the management of brain metastases from renal cell carcinoma remains unclear. To improve patient care, the authors sought to standardize practical management strategies. They performed an unstructured literature review and elaborated on the current management strategies through an international group of experts from different disciplines assembled via the network of the International Kidney Cancer Coalition. Experts from different disciplines were administered a survey to answer questions related to current challenges and unmet patient needs. On the basis of the integrated approach of literature review and survey study results, the authors built algorithms for the management of single and multiple brain metastases in patients with renal cell carcinoma. The literature review, consensus statements, and algorithms presented in this report can serve as a framework guiding treatment decisions for patients. CA Cancer J Clin. 2022;72:454-489.

The Role of Stereotactic Ablative Body Radiotherapy in Renal Cell Carcinoma

CONTEXT

Stereotactic ablative body radiotherapy (SABR) is an emerging treatment modality for primary and metastatic renal cell carcinoma (RCC).

OBJECTIVE

To review and summarise the evidence on the use of SABR in RCC in a narrative review.

EVIDENCE ACQUISITION

We performed an online search of the PubMed database from January 2000 through December 2021. Studies of SABR/stereotactic radiosurgery (SRS) targeting primary, extracranial, or intracranial metastatic RCC were included.

EVIDENCE SYNTHESIS

Two meta-analyses (including 54 studies), and 13 prospective and 20 retrospective studies were included in this review. In aggregate, SABR for 589 primary RCCs in 575 patients resulted in a local control rate of above 90% with grade 3-4 toxicity of 0-9%. Similarly, the local control rate ranged between 90% and 97% with SRS in 1225 patients with intracranial metastatic RCC. SABR was able to delay systemic therapy for at least 1 yr in 70-90% of oligometastatic RCC patients with grade 3-4 toxicity of <10%. As per the early data, the combination of SABR with systemic therapy for metastatic RCC, such as targeted therapy or immunotherapy, appears safe, feasible, and tolerable.

CONCLUSIONS

We outlined data supporting SABR in the key clinical scenarios of primary and metastatic, including oligometastatic, RCC in lieu of systemic therapy, in combination with systemic therapy, and palliation of brain and spinal metastases.

PATIENT SUMMARY

Stereotactic ablative body radiotherapy (SABR) is a relatively new treatment option in kidney cancer. Here, we review the published literature on the experience of using SABR in kidney cancer. The accumulated evidence demonstrates that SABR can be used safely and effectively to treat selected cases of primary or secondary kidney cancer.

Management of Metastatic Clear Cell Renal Cell Carcinoma: ASCO Guideline

PURPOSE

To provide recommendations for the management of patients with metastatic clear cell renal cell carcinoma (ccRCC).

METHODS

An Expert Panel conducted a systematic literature review to obtain evidence to guide treatment recommendations.

RESULTS

The panel considered peer-reviewed reports published in English.

RECOMMENDATIONS

The diagnosis of metastatic ccRCC should be made using tissue biopsy of the primary tumor or a metastatic site with the inclusion of markers and/or stains to support the diagnosis. The International Metastatic RCC Database Consortium risk criteria should be used to inform treatment. Cytoreductive nephrectomy may be offered to select patients with kidney-in-place and favorable- or intermediate-risk disease. For those who have already had a nephrectomy, an initial period of active surveillance may be offered if they are asymptomatic with a low burden of disease. Patients with favorable-risk disease who need systemic therapy may be offered an immune checkpoint inhibitor (ICI) in combination with a vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitor (TKI); patients with intermediate or poor risk should be offered a doublet regimen (no recommendation was provided between ICIs or an ICI in combination with a VEGFR TKI). For select patients, monotherapy with either an ICI or a VEGFR TKI may be offered on the basis of comorbidities. Interleukin-2 remains an option, although selection criteria could not be identified. Recommendations are also provided for second- and subsequent-line therapy as well as the treatment of bone metastases, brain metastases, or the presence of sarcomatoid features. Participation in clinical trials is highly encouraged for patients with metastatic ccRCC.Additional information is available at www.asco.org/genitourinary-cancer-guidelines.

Metastatic Clear-Cell Renal Cell Carcinoma in the Era of Immune Checkpoint Inhibitors: Therapies and Ongoing Trials

Immune checkpoint inhibitors (ICI) are now the bedrock for the treatment of metastatic renal cell carcinoma (RCC). Clear cell RCC (ccRCC) represents the most common subtype of this malignancy. Herein, we explore the therapeutic landscape of ccRCC by discussing the standard of care whose backbone consists of immune checkpoint inhibitors (ICI) and vascular endothelial growth factor inhibitors (VEGF). For ccRCC, pembrolizumab-axitinib, pembrolizumab-lenvatinib, and avelumab-axitinib or nivolumab-cabozantinib are now FDA-approved frontline options for all risk groups while nivolumab-ipilimumab is reserved for intermediate- and poor-risk groups. Monotherapy with pembrolizumab or nivolumab is a potential option for patients who are unable to take VEGFR-tyrosine kinase inhibitors. While outcomes have improved with the adoption of ICI therapies, many patients develop therapy-resistant disease, creating an unmet need for further investigation. The efficacy of novel therapies as well as novel combinations in the post-ICI era is unclear. This review summarizes the most significant clinical trials involving dual ICI/ICI and ICI/VEGFR therapies, in addition to other selected combination therapies that are likely to inform management in the near future.

An Evaluation of Cabozantinib for the Treatment of Renal Cell Carcinoma: Focus on Patient Selection and Perspectives

Cabozantinib is an oral tyrosine kinase inhibitor (TKI) with activity against several receptors involved in the angiogenesis pathway, including vascular endothelial growth factor receptor (VEGFR), c-MET and AXL. The antiangiogenic properties of cabozantinib led to its use as a monotherapy for the treatment of metastatic renal cell cancer (RCC), and quickly resulted in this treatment becoming part of the standard of care for these tumors. Since the advent of immune checkpoint inhibitors (ICIs), new standards of care have emerged in first-line settings, involving dual ICI or ICI–VEGF-TKI (including ICI–cabozantinib) combination treatments, and leading to a more complex algorithm of care. Cabozantinib remains an option in second-line settings and is still a first-line standard of care treatment in cases where the use of ICIs is contraindicated. This review focuses on the selection of patients who may benefit most from cabozantinib therapy, including those with bone and brain metastases and those with a non-clear cell RCC histology. The need to consider disease-related symptoms, comorbidities, age, drug interactions and biomarker analyses in the choice of therapeutic strategy is also highlighted. Finally, the perspectives for the use of cabozantinib in RCC treatment are discussed.

Cabozantinib as First-line Treatment in Patients With Metastatic Collecting Duct Renal Cell Carcinoma: Results of the BONSAI Trial for the Italian Network for Research in Urologic-Oncology (Meet-URO 2 Study)

Importance

Metastatic collecting duct carcinoma (mCDC) is a rare type of non-clear cell renal cell carcinoma (ncRCC) with poor prognosis and no standard treatments. Despite retrospective series that have documented the benefit of cabozantinib in ncRCC, no prospective trials have evaluated this treatment in mCDC.

Objective

To determine whether cabozantinib is an active treatment in patients with mCDC.

Design, Setting, and Participants

The caBozantinib in cOllectiNg ductS Renal Cell cArcInoma (BONSAI) trial was an open-label, single-arm, phase 2 clinical trial carried out between January 2018 and November 2020 at a single academic center with data cut off in September 2021 on behalf of the the Italian Network for Research in Urologic-Oncology (Meet-URO 2). Eligible patients had histologic diagnosis of centrally confirmed mCDC with measurable disease according to Response Evaluation Criteria in Solid Tumors (RECIST; version 1.1). In total, 25 patients were screened.

Interventions

Patients received cabozantinib, 60 mg orally once daily, until disease progression, unacceptable toxic effects, or withdrawal of consent.

Main Outcomes and Measures

The primary end point was objective response rate (ORR) per RECIST, version 1.1.

Results

At data cut off, of 25 patients enrolled, 23 started treatment because 2 were excluded after failing the screening process at pathologic review. The median follow-up cannot be estimated using the reverse Kaplan-Meier estimator. The median time to censoring was 11 months (95% CI, 0-22 months). Median (range) age was 66 (53-74) years. As best overall response, 3 patients presented stable disease, 1 patient achieved a complete response, and 7 a partial response. The ORR was 35% (95% CI, 16%-57%). The median progression-free survival was 4 months (95% CI, 3-13 months). The median OS was 7 months (95% CI, 3-31 months). All patients reported at least 1 grade (G) 1 to 2 adverse event (AE). The most common G1 to G2 AEs were fatigue (14 [60%]), anorexia (9 [39%]), hand-foot syndrome (7 [30%]), hypothyroidism (7 [30%]), mucositis (7 [30%]), diarrhea (5 [22%]), and hypertension (3 [13%]). Six G3 AEs were reported: 2 arterial hyperthension, 1 pulmonary thromboembolism, 1 bleeding, and 2 fatigue. There were no permanent discontinuations from the study owing to AEs. Four patients (17%) required dose reduction to 40 mg, and 4 (17%) required a transitory interruption to manage toxic effects.

Conclusions and Relevance

The study met the ORR primary end point, showing encouraging efficacy of cabozantinib in untreated patients with mCDC. Further investigations to advance the molecular understanding of this tumor are ongoing.

Trial Registration

ClinicalTrials.gov Identifier: NCT03354884.

Exposure-response analyses of cabozantinib in patients with metastatic renal cell cancer

Aim

In the registration trial, cabozantinib exposure ≥ 750 ng/mL correlated to improved tumor size reduction, response rate and progression free survival (PFS) in patients with metastatic renal cell cancer (mRCC). Because patients in routine care often differ from patients in clinical trials, we explored the cabozantinib exposure–response relationship in patients with mRCC treated in routine care.

Methods

Cabozantinib trough concentrations (C_min) were collected and average exposure was calculated per individual. Exposure–response analyses were performed using the earlier identified target of C_min > 750 ng/mL and median C_min. In addition, the effect of dose reductions on response was explored. PFS was used as measure of response.

Results

In total, 59 patients were included:10% were classified as favourable, 61% as intermediate and 29% as poor IMDC risk group, respectively. Median number of prior treatment lines was 2 (0–5). Starting dose was 60 mg in 46%, 40 mg in 42% and 20 mg in 12% of patients. Dose reductions were needed in 58% of patients. Median C_min was 572 ng/mL (IQR: 496–701). Only 17% of patients had an average C_min ≥ 750 ng/mL. Median PFS was 52 weeks (95% CI: 40–64). No improved PFS was observed for patients with C_min ≥ 750 ng/mL or ≥ 572 ng/ml. A longer PFS was observed for patients with a dose reduction vs. those without (65 vs. 31 weeks, p = .001). After incorporating known covariates (IMDC risk group and prior treatment lines (< 2 vs. ≥ 2)) in the multivariable analysis, the need for dose reduction remained significantly associated with improved PFS (HR 0.32, 95% CI:0.14–0.70, p = .004).

Conclusion

In these explorative analyses, no clear relationship between increased cabozantinib exposure and improved PFS was observed. Average cabozantinib exposure was below the previously proposed target in 83% of patients. Future studies should focus on validating the cabozantinib exposure required for long term efficacy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09338-1.

First-line Immune Checkpoint Inhibitor Combinations in Metastatic Renal Cell Carcinoma: Where Are We Going, Where Have We Been?

The combination of targeted therapy and immunotherapy in the treatment of metastatic renal cell carcinoma (mRCC) has significantly improved outcomes for many patients. There are multiple FDA-approved regimens for the frontline setting based on numerous randomized Phase III trials. Despite these efforts, there remains a conundrum of identifying a biomarker-driven approach for these patients and it is unclear how to predict which patients are most likely to respond to these agents. This is due, in part, to an incomplete understanding of how these drug combinations work. The use of tyrosine kinase inhibitors that have multiple 'off-target' effects may lend themselves to the benefits observed when given in combination with immunotherapy. Further, targeting multiple clones within a patient's heterogenic tumor that are responsive to targeted therapy and others that are responsive to immunotherapy may also explain some level of improved response rates to the combination approaches compared to monotherapies. This review highlights the 5 FDA-approved regimens for mRCC in the frontline setting and offers insights into potential mechanisms for improved outcomes seen in these combination approaches.

Cabozantinib Is Effective in Melanoma Brain Metastasis Cell Lines and Affects Key Signaling Pathways

Melanomas have a high potential to metastasize to the brain. Recent advances in targeted therapies and immunotherapies have changed the therapeutical landscape of extracranial melanomas. However, few patients with melanoma brain metastasis (MBM) respond effectively to these treatments and new therapeutic strategies are needed. Cabozantinib is a receptor tyrosine kinase (RTK) inhibitor, already approved for the treatment of non-skin-related cancers. The drug targets several of the proteins that are known to be dysregulated in melanomas. The anti-tumor activity of cabozantinib was investigated using three human MBM cell lines. Cabozantinib treatment decreased the viability of all cell lines both when grown in monolayer cultures and as tumor spheroids. The in vitro cell migration was also inhibited and apoptosis was induced by cabozantinib. The phosphorylated RTKs p-PDGF-Rα, p-IGF-1R, p-MERTK and p-DDR1 were found to be downregulated in the p-RTK array of the MBM cells after cabozantinib treatment. Western blot validated these results and showed that cabozantinib treatment inhibited p-Akt and p-MEK 1/2. Further investigations are warranted to elucidate the therapeutic potential of cabozantinib for patients with MBM.