Targeted therapies in brain metastases

Impact of Broadening Trial Eligibility Criteria on the Inclusion of Patients With Brain Metastases in Cancer Clinical Trials: Time Series Analyses for 2012-2022

PURPOSE

In October 2017, an ASCO, Friends of Cancer Research (FoCR), and US Food and Drug Administration (ASCO/FoCR/FDA) task force recommended that common eligibility criteria be modified to make trials more inclusive. We examined whether patterns of exclusions regarding patients with brain metastases changed over time in relation to these recommendations.

METHODS

Trial eligibility criteria were abstracted from ClinicalTrials.gov for phase I-III US-based interventional clinical trials for patients with advanced breast, colorectal, lung, or melanoma cancers from January 2012 to December 2022. Trials were examined to determine whether patients with brain metastases were not excluded, conditionally excluded (ie, excluded in some circumstances), or wholly excluded. An interrupted time series analysis with multinomial logistic regression was used to determine whether the ASCO/FoCR/FDA recommendations were associated with changes in brain metastases criteria.

RESULTS

We evaluated N = 3,077 trials. Patients with brain metastases were not excluded in 506 trials (16.4%), conditionally excluded in 2,263 trials (73.5%), and wholly excluded in 308 trials (10.0%). In the postrecommendation period, we estimated a 68% increase in the odds of brain metastases not excluded compared with conditionally excluded (odds ratio, 1.68 [95% CI, 1.06 to 2.66], P = .03). The proportion of trials in which patients with brain metastases were not excluded increased (from 11.5% v 17.3%) and conditionally excluded decreased (from 82.3% to 75.2%, P = .03). We found no difference in the proportion of trials in which patients with brain metastases were wholly excluded (7.5% v 6.2%, P = .42).

CONCLUSION

The ASCO/FoCR/FDA task force recommendations were associated with a shift in patterns of brain metastases exclusion criteria from conditionally excluded to not excluded. These findings demonstrate that the cancer clinical trial community has begun to change the way trials are written to be more inclusive.

Amplifying the Patient's Voice in Oncology Early-Phase Clinical Trials: Solutions to Burdens and Barriers

Dose-finding oncology trials (DFOTs) provide early access to novel compounds of potential therapeutic benefit in addition to providing critical safety and dosing information. While access to trials for which a patient is eligible remains the largest barrier to enrollment on clinical trials, additional direct and indirect barriers unique to enrollment on DFOTs are often overlooked but worthy of consideration. Direct barriers including financial costs of care, travel and time investments, and logical challenges including correlative study designs are important to bear in mind when developing strategies to facilitate the patient experience on DFOTs. Indirect barriers such as strict eligibility criteria, washout periods, and concomitant medication restrictions should be accounted for during DFOT design to maintain the fidelity of the trial without being overly exclusionary. Involving patients and advocates and incorporating patient-reported outcomes (PROs) throughout the process, from initial DFOT design, through patient recruitment and participation, is critical to informing strategies to minimize identified barriers to offer the benefit of DFOTs to all patients.

Identification of a novel peptide ligand for the cancer-specific receptor mutation EGFRvIII using high-throughput sequencing of phage-selected peptides

We report here the selection and characterization of a novel peptide ligand using phage display targeted against the cancer-specific epidermal growth factor tyrosine kinase receptor mutation variant III (EGFRvIII). This receptor is expressed in several kinds of cancer: ovarian cancer, breast cancer and glioblastoma, but not in normal tissues. A 12-mer random peptide library was screened against EGFRvIII. Phage-selected peptides were sequenced in high-throughput by next generation sequencing (NGS), and their diversity was studied to identify highly abundant clones expected to bind with the highest affinities to EGFRvIII. The enriched peptides were characterized and their binding capacity towards stable cell lines expressing EGFRvIII, EGFR wild type (EGFR WT), or a low endogenous level of EGFR WT was confirmed by flow cytometry analysis. The best peptide candidate, VLGREEWSTSYW, was synthesized, and its binding specificity towards EGFRvIII was validated in vitro. Additionally, computational docking analysis suggested that the identified peptide binds selectively to EGFRvIII. The novel VLGREEWSTSYW peptide is thus a promising EGFRvIII-targeting agent for future applications in cancer diagnosis and therapy.

Recent Trends in Synchronous Brain Metastasis Incidence and Mortality in the United States: Ten-Year Multicenter Experience

BACKGROUND

Large epidemiological studies describing the trends in incidence rates and mortality of synchronous brain metastases (SBMs) are lacking. The study aimed to provide a comprehensive understanding of the changes in the incidence and mortality of SBMs over the previous ten years.

METHODS

Trends in the incidence of solid malignancies outside of the CNS in patients with SBMs and incidence-based mortality rates were assessed using data from the Surveillance, Epidemiology, and End Results database. Joinpoint analyses were used to calculate annual percent changes (APCs) and 95% CIs.

RESULTS

Between 2010 and 2019, 66,655 patients, including 34,821 (52.24%) men and 31,834 (47.76%) women, were found to have SBMs, and 57,692 deaths occurred over this period. Lung cancer SBMs, melanoma SBMs, and breast cancer SBMs were ranked in the top three, having the highest age-standardized incidence rates. The incidence of SBMs decreased significantly with an APC of -0.6% from 2010 to 2019, while the APC was 1.2% for lung cancer SBMs, 2.5% for melanoma SBMs, and 0.6% for breast cancer SBMs. The SBM mortality first experienced a rapid increase (APC = 28.6%) from 2010 to 2012 and then showed a significant decline at an APC of -1.8% from 2012 to 2019. Lung cancer SBMs showed similar trends, while melanoma SBM and breast cancer SBM mortality increased continuously.

CONCLUSIONS

SBMs incidence (2010-2019) and incidence-based mortality (2012-2019) declined significantly. These findings can advance our understanding of the prevalence of SBMs.

Fluorescein-guided resection of cerebral metastases is associated with greater tumor resection

BACKGROUND

Sodium fluorescein (fluorescein) crosses a disrupted blood-brain barrier similarly to gadolinium contrast in contrast-enhancing cerebral tumors. When exposed to light with 560 nm wavelength during surgery, fluorescein emits a yellow-green fluorescent light that can be visualized through an operating microscope equipped with an appropriate emission filter. The distribution of the fluorescence correlates with the contrast on a gadolinium contrast-enhanced MRI.

OBJECTIVE

The objective of this single-center retrospective study was to investigate if the use of fluorescein would increase the extent of resection and to examine if fluorescein guided resection influences postoperative neurological status.

METHODS

During the study period from August 2014 to August 2018, 117 patients were operated for cerebral metastases. Of these, 56 operations were guided by fluorescein and 61 by traditional white light. All patients had an early postoperative MRI within 72 h after surgery.

RESULTS

The use of fluorescein increased the extent of resection in patients with cerebral metastases. The use of fluorescein was not associated with increased postoperative sequelae or neurological damage regardless of underlying primary cancer.

CONCLUSION

Fluorescein is a helpful supplement in the neurosurgical treatment of cerebral metastases.

Two case reports of brain metastases in patients with pancreatobiliary neuroendocrine carcinoma

Brain metastases are extremely rare in patients with pancreatobiliary neuroendocrine caricnoma (PB-NEC). In this case report, we report two rare cases of brain metastases in patients with PB-NEC. Each patient was diagnosed with brain metastases five and ten months after the initial diagnosis of PB-NEC. It is noteworthy that the serum tumor marker neuron-specific enolase (NSE) or pro-gastrin-releasing peptide (Pro-GRP) was elevated, although the primary and metastatic lesions other than in the brain were under control with systemic chemotherapy. Moreover, the patients complained of no neurological symptoms until they were diagnosed with brain metastases. Although the incidence of brain metastases of PB-NEC is exceedingly low, it is important to keep in mind the possibility of brain metastases during the course of treatment for PB-NEC. In addition, we discuss a strategy of treatment and screening for brain metastases of PB-NEC in this case report.

Clinical effects of apatinib mesylate for treatment of multiple brain micrometastases: Two case reports

BACKGROUND

Apatinib is a small-molecule multitargeted tyrosine kinase inhibitor. Apatinib has demonstrated encouraging antitumor activities. This study aimed to observe the efficacy and safety of apatinib for the treatment of multiple brain micrometastases.

CASE SUMMARY

We report two patients with multiple brain micrometastases after failure of second-line treatment. Both patients had extracerebral metastases. When the patients took 250 mg/d apatinib orally, the intracerebral lesions disappeared. The extracerebral lesions were partially alleviated. Both patients had a progression-free survival of more than 12 mo and were still stable. The safety was good. The main adverse events (AEs) were mild hypertension and proteinuria, which could be controlled.

CONCLUSION

Apatinib has clear efficacy and good tolerance in patients with multiple brain micrometastases after failure of second-line treatment.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines on Treatment Options for Adults With Multiple Metastatic Brain Tumors

TARGET POPULATION

These recommendations apply to adult patients newly diagnosed with multiple (more than 1) brain metastases.

QUESTION 1

In what circumstances should whole brain radiation therapy be recommended to improve tumor control and survival in patients with multiple brain metastases?

RECOMMENDATION

Level 2: It is recommended that whole brain radiation therapy can be added to stereotactic radiosurgery to improve local and distant control keeping in mind the potential for worsened neurocognitive outcomes and that there is unlikely to be a significant impact on overall survival.

QUESTION 2

In what circumstances should stereotactic radiosurgery be recommended to improve tumor control and survival in patients with multiple brain metastases?

RECOMMENDATIONS

Level 1: In patients with 2 to 3 brain metastases not amenable to surgery, the addition of stereotactic radiosurgery to whole brain radiation therapy is not recommended to improve survival beyond that obtained with whole brain radiation therapy alone. Level 3: The use of stereotactic radiosurgery alone is recommended to improve median overall survival for patients with more than 4 metastases having a cumulative volume < 7 cc.

QUESTION 3

In what circumstances should surgery be recommended to improve tumor control and survival in patients with multiple brain metastases?

RECOMMENDATION

Level 3: In patients with multiple brain metastases, tumor resection is recommended in patients with lesions inducing symptoms from mass effect that can be reached without inducing new neurological deficit and who have control of their cancer outside the nervous system.The full guideline can be found at https://www.cns.org/guidelines/guidelines-treatment-adults-metastatic-brain-tumors/chapter_6.

Epidemiology, Treatment, and Complications of Central Nervous System Metastases

PURPOSE OF REVIEW

Neurologic problems resulting from systemic cancer metastases to brain parenchyma, dura, spinal cord, and leptomeninges are among the most common types of consultations addressed by neurologists. With patients surviving longer from systemic cancer, along with the rapidly evolving therapeutic options, the treatment of these devastating complications has become both more effective and more complicated. This article reviews current patterns of metastatic disease and the increasingly nuanced landscape of evolving therapies, their complications, and their impact on quality of survival.

RECENT FINDINGS

Targeted therapies with tyrosine kinase inhibitors and immune checkpoint inhibitors and cytotoxic therapies directed at disease-specific chemosensitivity patterns have dramatically improved the prognosis of non-small cell lung cancer, melanoma, and breast cancer, but have led to some novel complications and altered recurrence patterns. Clinical trials suggest the superiority of hippocampal-avoidance radiation fields and the use of stereotactic radiosurgery over whole-brain radiation therapy to minimize long-term cognitive consequences of radiation therapy. Emerging data document tolerable safety when brain radiation is combined with immunotherapy. Chemotherapy can be a first-line treatment for some inoperable brain metastases, eliminating or deferring whole-brain radiation therapy. Stereotactic body radiation therapy is a new technique of radiation used for spinal and epidural metastases that spares spinal cord tissue while ablating tumors.

SUMMARY

Metastases to the nervous system remain devastating, but their prognosis and therapies are more heterogeneous than previously appreciated. Neurologists now can offer more personalized prognostic information based on new stratification criteria, can predict drug complications relevant to the nervous system, and can provide critical partnership in the multidisciplinary effort to balance effective longer-term disease control with treatment-related adverse consequences.

Mechanisms and Therapy for Cancer Metastasis to the Brain

Advances in chemotherapy and targeted therapies have improved survival in cancer patients with an increase of the incidence of newly diagnosed brain metastases (BMs). Intracranial metastases are symptomatic in 60–70% of patients. Magnetic resonance imaging (MRI) with gadolinium is more sensitive than computed tomography and advanced neuroimaging techniques have been increasingly used in the detection, treatment planning, and follow-up of BM. Apart from the morphological analysis, the most effective tool for characterizing BM is immunohistochemistry. Molecular alterations not always reflect those of the primary tumor. More sophisticated methods of tumor analysis detecting circulating biomarkers in fluids (liquid biopsy), including circulating DNA, circulating tumor cells, and extracellular vesicles, containing tumor DNA and macromolecules (microRNA), have shown promise regarding tumor treatment response and progression. The choice of therapeutic approaches is guided by prognostic scores (Recursive Partitioning Analysis and diagnostic-specific Graded Prognostic Assessment-DS-GPA). The survival benefit of surgical resection seems limited to the subgroup of patients with controlled systemic disease and good performance status. Leptomeningeal disease (LMD) can be a complication, especially in posterior fossa metastases undergoing a “piecemeal” resection. Radiosurgery of the resection cavity may offer comparable survival and local control as postoperative whole-brain radiotherapy (WBRT). WBRT alone is now the treatment of choice only for patients with single or multiple BMs not amenable to surgery or radiosurgery, or with poor prognostic factors. To reduce the neurocognitive sequelae of WBRT intensity modulated radiotherapy with hippocampal sparing, and pharmacological approaches (memantine and donepezil) have been investigated. In the last decade, a multitude of molecular abnormalities have been discovered. Approximately 33% of patients with non-small cell lung cancer (NSCLC) tumors and epidermal growth factor receptor mutations develop BMs, which are targetable with different generations of tyrosine kinase inhibitors (TKIs: gefitinib, erlotinib, afatinib, icotinib, and osimertinib). Other “druggable” alterations seen in up to 5% of NSCLC patients are the rearrangements of the “anaplastic lymphoma kinase” gene TKI (crizotinib, ceritinib, alectinib, brigatinib, and lorlatinib). In human epidermal growth factor receptor 2-positive, breast cancer targeted therapies have been widely used (trastuzumab, trastuzumab-emtansine, lapatinib-capecitabine, and neratinib). Novel targeted and immunotherapeutic agents have also revolutionized the systemic management of melanoma (ipilimumab, nivolumab, pembrolizumab, and BRAF inhibitors dabrafenib and vemurafenib).

Stereotactic Radiosurgery in the Management of Patients With Brain Metastases of Non-Small Cell Lung Cancer: Indications, Decision Tools and Future Directions

Brain metastases (BM) frequently occur in non-small cell lung cancer (NSCLC) patients. Most patients with BM have a limited life expectancy, measured in months. Selected patients may experience a very long progression-free survival, for example, patients with a targetable driver mutation. Traditionally, whole-brain radiotherapy (WBRT) has been the cornerstone of the treatment, but its indication is a matter of debate. A randomized trial has shown that for patients with a poor prognosis, WBRT does not add quality of life (QoL) nor survival over the best supportive care. In recent decades, stereotactic radiosurgery (SRS) has become an attractive non-invasive treatment for patients with BM. Only the BM is irradiated to an ablative dose, sparing healthy brain tissue. Intracranial recurrence rates decrease when WBRT is administered following SRS or resection but does not improve overall survival and comes at the expense of neurocognitive function and QoL. The downside of SRS compared with WBRT is a risk of radionecrosis (RN) and a higher risk of developing new BM during follow-up. Currently, SRS is an established treatment for patients with a maximum of four BM. Several promising strategies are currently being investigated to further improve the indication and outcome of SRS for patients with BM: the effectivity and safety of SRS in patients with more than four BM, combining SRS with systemic therapy such as targeted agents or immunotherapy, shared decision-making with SRS as a treatment option, and individualized isotoxic dose prescription to mitigate the risk of RN and further enhance local control probability of SRS. This review discusses the current indications of SRS and future directions of treatment for patients with BM of NSCLC with focus on the value of SRS.

Proteomics-based insights into mitogen-activated protein kinase inhibitor resistance of cerebral melanoma metastases

Background

MAP kinase inhibitor (MAPKi) therapy for BRAF mutated melanoma is characterized by high response rates but development of drug resistance within a median progression-free survival (PFS) of 9-12 months. Understanding mechanisms of resistance and identifying effective therapeutic alternatives is one of the most important scientific challenges in melanoma. Using proteomics, we want to specifically gain insight into the pathophysiological process of cerebral metastases.

Methods

Cerebral metastases from melanoma patients were initially analyzed by a LC-MS shotgun approach performed on a QExactive HF hybrid quadrupole-orbitrap mass spectrometer. For further validation steps after bioinformatics analysis, a targeted LC-QQQ-MS approach, as well as Western blot, immunohistochemistry and immunocytochemistry was performed.

Results

In this pilot study, we were able to identify 5977 proteins by LC-MS analysis (data are available via ProteomeXchange with identifier PXD007592). Based on PFS, samples were classified into good responders (PFS ≥ 6 months) and poor responders (PFS [Formula: see text] 3 months). By evaluating these proteomic profiles according to gene ontology (GO) terms, KEGG pathways and gene set enrichment analysis (GSEA), we could characterize differences between the two distinct groups. We detected an EMT feature (up-regulation of N-cadherin) as classifier between the two groups, V-type proton ATPases, cell adhesion proteins and several transporter and exchanger proteins to be significantly up-regulated in poor responding patients, whereas good responders showed an immune activation, among other features. We identified class-discriminating proteins based on nearest shrunken centroids, validated and quantified this signature by a targeted approach and could correlate parts of this signature with resistance using the CPL/MUW proteome database and survival of patients by TCGA analysis. We further validated an EMT-like signature as a major discriminator between good and poor responders on primary melanoma cells derived from cerebral metastases. Higher immune activity is demonstrated in patients with good response to MAPKi by immunohistochemical staining of biopsy samples of cerebral melanoma metastases.

Conclusions

Employing proteomic analysis, we confirmed known extra-cerebral resistance mechanisms in the cerebral metastases and further discovered possible brain specific mechanisms of drug efflux, which might serve as treatment targets or as predictive markers for these kinds of metastasis.

Modernizing Clinical Trial Eligibility Criteria: Recommendations of the American Society of Clinical Oncology-Friends of Cancer Research Brain Metastases Working Group

Purpose Broadening trial eligibility to improve accrual and access and to better reflect intended-to-treat populations has been recognized as a priority. Historically, patients with brain metastases have been understudied, because of restrictive eligibility across all phases of clinical trials. Methods In 2016, after a literature search and series of teleconferences, a multistakeholder workshop was convened. Our working group focused on developing consensus recommendations regarding the inclusion of patients with brain metastases in clinical trials, as part of a broader effort that encompassed minimum age, HIV status, and organ dysfunction. The working group attempted to balance the needs of protecting patient safety, facilitating access to investigational therapies, and ensuring trial integrity. On the basis of input at the workshop, guidelines were further refined and finalized. Results The working group identified three key populations: those with treated/stable brain metastases, defined as patients who have received prior therapy for their brain metastases and whose CNS disease is radiographically stable at study entry; those with active brain metastases, defined as new and/or progressive brain metastases at the time of study entry; and those with leptomeningeal disease. In most circumstances, the working group encourages the inclusion of patients with treated/stable brain metastases in clinical trials. A framework of key considerations for patients with active brain metastases was developed. For patients with leptomeningeal disease, inclusion of a separate cohort in both early-phase and later-phase trials is recommended, if CNS activity is anticipated and when relevant to the specific disease type. Conclusion Expanding eligibility to be more inclusive of patients with brain metastasis is justified in many cases and may speed the development of effective therapies in this area of high clinical need.

Broadening Eligibility Criteria to Make Clinical Trials More Representative: American Society of Clinical Oncology and Friends of Cancer Research Joint Research Statement

Purpose The primary purposes of eligibility criteria are to protect the safety of trial participants and define the trial population. Excessive or overly restrictive eligibility criteria can slow trial accrual, jeopardize the generalizability of results, and limit understanding of the intervention's benefit-risk profile. Methods ASCO, Friends of Cancer Research, and the US Food and Drug Administration examined specific eligibility criteria (ie, brain metastases, minimum age, HIV infection, and organ dysfunction and prior and concurrent malignancies) to determine whether to modify definitions to extend trials to a broader population. Working groups developed consensus recommendations based on review of evidence, consideration of the patient population, and consultation with the research community. Results Patients with treated or clinically stable brain metastases should be routinely included in trials and only excluded if there is compelling rationale. In initial dose-finding trials, pediatric-specific cohorts should be included based on strong scientific rationale for benefit. Later phase trials in diseases that span adult and pediatric populations should include patients older than age 12 years. HIV-infected patients who are healthy and have low risk of AIDS-related outcomes should be included absent specific rationale for exclusion. Renal function criteria should enable liberal creatinine clearance, unless the investigational agent involves renal excretion. Patients with prior or concurrent malignancies should be included, especially when the risk of the malignancy interfering with either safety or efficacy endpoints is very low. Conclusion To maximize generalizability of results, trial enrollment criteria should strive for inclusiveness. Rationale for excluding patients should be clearly articulated and reflect expected toxicities associated with the therapy under investigation.

Targeted Therapies for the Treatment of Brain Metastases in Solid Tumors

Brain metastases are a major cause of morbidity and mortality in cancer patients. While the mainstay treatment comprises surgery and radiation therapy, the role of systemic agents remains controversial. In general, it has been presumed that poor blood-brain barrier (BBB) penetration and inherently more resistant metastatic brain disease preclude a favorable systemic treatment approach. However, a better understanding of tumor biology and the subsequent development of targeted drugs have reawakened interest in systemic therapy. Despite still limited brain distribution, a variety of targeted drugs have demonstrated activity in brain metastases in early clinical trials. Nevertheless, disease progression commonly occurs, and it remains to be elucidated whether limited CNS drug distribution or the acquisition of resistant metastatic clones must be held responsible for this prognosis. Moreover, micrometastatic brain disease beyond an intact BBB-and ultimately prevention of brain metastasis formation-may generally remain inaccessible for first-generation targeted agents with poor CNS penetration. To overcome limited brain distribution and possibly emerging acquired resistance, highly potent next-generation targeted drugs with enhanced CNS distribution have been developed. In view of this emerging but yet undefined role of targeted therapies in the treatment of brain metastases from solid tumors, this review aims to summarize the current knowledge from clinical trials and discusses clinically relevant obstacles to overcome.

Incidence and prognosis of patients with brain metastases at diagnosis of systemic malignancy: a population-based study

BACKGROUND

Brain metastases are associated with significant morbidity and mortality. Population-level data describing the incidence and prognosis of patients with brain metastases are lacking. The aim of this study was to characterize the incidence and prognosis of patients with brain metastases at diagnosis of systemic malignancy using recently released data from the Surveillance, Epidemiology, and End Results (SEER) program.

METHODS

We identified 1302166 patients with diagnoses of nonhematologic malignancies originating outside of the CNS between 2010 and 2013 and described the incidence proportion and survival of patients with brain metastases.

RESULTS

We identified 26430 patients with brain metastases at diagnosis of cancer. Patients with small cell and non-small cell lung cancer displayed the highest rates of identified brain metastases at diagnosis; among patients presenting with metastatic disease, patients with melanoma (28.2%), lung adenocarcinoma (26.8%), non-small cell lung cancer not otherwise specified/other lung cancer (25.6%), small cell lung cancer (23.5%), squamous cell carcinoma of the lung (15.9%), bronchioloalveolar carcinoma (15.5%), and renal cancer (10.8%) had an incidence proportion of identified brain metastases of >10%. Patients with brain metastases secondary to prostate cancer, bronchioloalveolar carcinoma, and breast cancer displayed the longest median survival (12.0, 10.0, and 10.0 months, respectively).

CONCLUSIONS

In this study we provide generalizable estimates of the incidence and prognosis for patients with brain metastases at diagnosis of a systemic malignancy. These data may allow for appropriate utilization of brain-directed imaging as screening for subpopulations with cancer and have implications for clinical trial design and counseling of patients regarding prognosis.

A framework for understanding and targeting residual disease in oncogene-driven solid cancers

Molecular targeted therapy has the potential to dramatically improve survival in patients with cancer. However, complete and durable responses to targeted therapy are rare in individuals with advanced-stage solid cancers. Even the most effective targeted therapies generally do not induce a complete tumor response, resulting in residual disease and tumor progression that limits patient survival. We discuss the emerging need to more fully understand the molecular basis of residual disease as a prelude to designing therapeutic strategies to minimize or eliminate residual disease so that we can move from temporary to chronic control of disease, or a cure, for patients with advanced-stage solid cancers. Ultimately, we propose a shift from the current reactive paradigm of analyzing and treating acquired drug resistance to a pre-emptive paradigm of defining the mechanisms that result in residual disease, to target and limit this disease reservoir.

Comparing available criteria for measuring brain metastasis response to immunotherapy

The response assessment in neuro-oncology (RANO) working group recently proposed standardized response criteria for brain metastases (RANO-BM). We sought to compare RANO-BM to other criteria in an ongoing brain metastasis trial. The first 36 patients enrolled on NCT02085070, an ongoing trial of pembrolizumab for patients with untreated brain metastases, were included in this analysis. As RANO-BM had not been proposed when the protocol was written, response on trial was assessed using an institutional modification of RECIST 1.1 (mRECIST), wherein minimum target brain lesion size was 5 mm in longest diameter and up to five target brain lesions were followed. We here additionally assessed response using standard RECIST 1.1, RANO high-grade glioma (RANO-HGG), and RANO-BM. Comparison between the four criteria sets using cases eligible across the board revealed excellent concordance (kappa statistic > 0.8), with only one discordant case. However, compared to RECIST 1.1 or RANO-BM, using a 5 mm threshold for target brain lesions in mRECIST allowed enrollment of 13 additional patients, five of whom had durable responses. Compared to RANO-HGG, 19 additional patients were enrolled using mRECIST, eight of whom had durable responses. Consequently, this resulted in response rates ranging from 12% with RANO-HGG to 28% with mRECIST. This study supports using a 5 mm threshold for target brain lesions when using high resolution MRI with ≤2 mm slices to facilitate accrual to similar clinical trials and provide earlier access to novel therapies for brain metastasis patients. Concordance among the four criteria studied was otherwise very high.

Best Practices in Treatment Selection for Patients With Advanced NSCLC

Worldwide, lung cancer is the most prevalent form of cancer, and its non-small-cell subtype constitutes up to 85% of cases. Overall, lung cancer is the most common cause of cancer-related death in the United States for both sexes, and its 5-year survival rate is 17%. It is a heterogeneous disease characterized by a variety of biomarkers and differing histologies. Non-small-cell lung cancer may be squamous or nonsquamous in nature and fueled by a number of oncodrivers. Obtaining sufficient tissue during biopsy to perform thorough biomarker testing is a challenge but essential for the modern, targeted therapeutic environment. Although platinum-based doublets still play a major role in first-line treatment, novel therapeutic agent targeting BRAF, EGFR, ALK, and ROS1, as well as agents targeting the T790M mutation, may offer options for patients whose disease fails to respond to initial therapy or relapses following an initial response. The emergence of immunotherapy as second-line standard therapy has changed the treatment paradigm. Some patients will have more favorable outcomes in the first-line setting with immunotherapy. However, managing lung cancer has become more complex than it was 15 years ago when the challenge of treatment was seen as being only binary, ie, small-cell vs non-small-cell disease.

Brain metastasis: Unique challenges and open opportunities

The metastasis of cancer to the central nervous system (CNS) remains a devastating clinical reality, carrying an estimated survival time of less than one year in spite of recent therapeutic breakthroughs for other disease contexts. Advances in brain metastasis research are hindered by a number of factors, including its complicated nature and the difficulty of modeling metastatic cancer growth in the unique brain microenvironment. In this review, we will discuss the clinical challenge, and compare the merits and limitations of the available models for brain metastasis research. Additionally, we will specifically address current knowledge on how brain metastases take advantage of the unique brain environment to benefit their own growth. Finally, we will explore the distinctive metabolic and chemical characteristics of the brain and how these paradoxically represent barriers to establishment of brain metastasis, but also provide ample supplies for metastatic cells' growth in the brain. We envision that multi-disciplinary innovative approaches will open opportunities for the field to make breakthroughs in tackling unique challenges of brain metastasis.

Timing and type of immune checkpoint therapy affect the early radiographic response of melanoma brain metastases to stereotactic radiosurgery

BACKGROUND

Growing evidence suggests that immunotherapy and radiation therapy can be synergistic in the treatment of cancer. This study was performed to determine the effect of the relative timing and type of immune checkpoint therapy on the response of melanoma brain metastases (BrMets) to treatment with stereotactic radiosurgery (SRS).

METHODS

Seventy-five melanoma patients with 566 BrMets were treated with both SRS and immune checkpoint therapy between 2007 and 2015 at a single institution. Immunotherapy and radiosurgery treatment of any single lesion were considered concurrent if SRS was administered within 4 weeks of immunotherapy. The impact of the timing and type of immunotherapy on the lesional response was determined with the Wilcoxon rank-sum test, which was used to compare the median percent lesion volume change 1.5, 3, and 6 months after SRS treatment, with significance determined by P = .0167 according to the Bonferroni correction for multiple comparisons.

RESULTS

Concurrent use of immunotherapy and SRS resulted in a significantly greater median percent reduction in the lesion volume at 1.5 (-63.1% vs -43.2%, P < .0001), 3 (-83.0% vs -52.8%, P < .0001), and 6 months (-94.9% vs -66.2%, P < .0001) in comparison with nonconcurrent therapy. The median percent reduction in the lesion volume was also significantly greater for anti-programmed cell death protein 1 (anti-PD-1) than anti-cytotoxic T-lymphocyte-associated protein 4 (anti-CTLA-4) at 1.5 (-71.1% vs -48.2%, P < .0001), 3 (-89.3% vs -66.2%, P < .0001), and 6 months (-95.1% vs -75.9%, P = .0004).

CONCLUSIONS

The administration of immunotherapy within 4 weeks of SRS results in an improved lesional response of melanoma BrMets in comparison with treatment separated by longer than 4 weeks. Anti-PD-1 therapy also results in a greater lesional response than anti-CTLA-4 after SRS. Cancer 2016;122:3051-3058. © 2016 American Cancer Society.

Pharmacokinetic Properties of Anticancer Agents for the Treatment of Central Nervous System Tumors: Update of the Literature

Despite significant improvement in outcomes for patients with hematologic malignancies and solid tumors over the past 10 years, patients with primary or metastatic brain tumors continue to have a poor prognosis. A primary reason for this is the inability of many chemotherapeutic drugs to penetrate into the brain and brain tumors at concentrations high enough to exert an antitumor effect because of unique barriers and efflux transporters. Several studies have been published recently examining the central nervous system pharmacokinetics of various anticancer drugs in patients with primary and metastatic brain tumors. To summarize recent advances in the field, this review critically presents studies published within the last 9 years examining brain and cerebrospinal fluid penetration of clinically available anticancer agents for patients with central nervous system tumors.

Quantitative [Fe]MRI of PSMA-targeted SPIONs specifically discriminates among prostate tumor cell types based on their PSMA expression levels

We report the development, experimental verification, and application of a general theory called [Fe]MRI (pronounced fem-ree) for the non-invasive, quantitative molecular magnetic resonance imaging (MRI) of added magnetic nanoparticles or other magnetic contrast agents in biological tissues and other sites. [Fe]MRI can easily be implemented on any MRI instrument, requiring only measurements of the background nuclear magnetic relaxation times (T₁, T₂) of the tissue of interest, injection of the magnetic particles, and the subsequent acquisition of a pair of T₁-weighted and T₂-weighted images. These images, converted into contrast images, are subtracted to yield a contrast difference image proportional to the absolute nanoparticle, iron concentration, ([Fe]) image. [Fe]MRI was validated with the samples of superparamagnetic iron oxide nanoparticles (SPIONs) both in agarose gels and bound to human prostate tumor cells. The [Fe]MRI measurement of the binding of anti-prostate specific membrane antigen (PSMA) conjugated SPIONs to PSMA-positive LNCaP and PSMA-negative DU145 cells in vitro allowed a facile discrimination among prostate tumor cell types based on their PSMA expression level. The low [Fe] detection limit of ~2 μM for SPIONs allows sensitive MRI of added iron at concentrations considerably below the US Food and Drug Administration’s human iron dosage guidelines (<90 μM, 5 mg/kg).

The Rationale for Targeted Therapies and Stereotactic Radiosurgery in the Treatment of Brain Metastases

Brain metastases are the most common intracranial malignancy. Many approaches, including radiation therapy, surgery, and cytotoxic chemotherapy, have been used to treat patients with brain metastases depending on the patient's disease burden and symptoms. However, stereotactic surgery (SRS) has revolutionized local treatment of brain metastases. Likewise, targeted therapies, including small-molecule inhibitors and monoclonal antibodies that target cancer cell metabolism or angiogenesis, have transformed managing systemic disease. Prospective data on combining these treatments for synergistic effect are limited, but early data show favorable safety and efficacy profiles. The combination of SRS and targeted therapy will further individualize treatment, potentially obviating the need for cytotoxic chemotherapy or whole-brain radiation. There is a great need to pursue research into these exciting modalities and novel combinations to further improve the treatment of patients with brain metastases. This article discusses reported and ongoing clinical trials assessing the safety and efficacy of targeted therapy during SRS.

IMPLICATIONS FOR PRACTICE

Treatment of patients with brain metastases requires a multidisciplinary approach. Stereotactic radiosurgery is increasingly used in the upfront setting to treat new brain metastasis. Targeted therapies have revolutionized systemic treatment of many malignancies and may sometimes be used as initial treatment in metastatic patients. There is sparse literature regarding safety and efficacy of combining these two treatment modalities. This article summarizes the supporting literature and highlights ongoing clinical trials in combining radiosurgery with targeted therapy.

Recent advances in the treatment of melanoma with BRAF and MEK inhibitors

Selective inhibition of the mitogen activated protein kinase (MAPK) pathway with either BRAF or MEK inhibition has emerged as the key component for the treatment of BRAF-mutant metastatic melanoma. New evidence from several phase III trials suggests that the combination of BRAF and MEK inhibitors improves tumor response rate and progression-free survival (PFS). Some of the serious adverse events, in particular, the incidence of cutaneous squamous cell carcinoma seen with the monotherapy treatment with a BRAF inhibitor are attenuated with combination therapy, whereas milder side effects such as pyrexia can be more common with combination therapy. Although dose reductions and dose interruptions are slightly more common with combination therapy, overall data supports the notion that combination therapy is safe and improves the outcomes for metastatic melanoma patients compared to single agent BRAF inhibitors.

CAVEOLIN-1 expression in brain metastasis from lung cancer predicts worse outcome and radioresistance, irrespective of tumor histotype

Brain metastases develop in one-third of patients with non-small-cell lung cancer and are associated with a dismal prognosis, irrespective of surgery or chemo-radiotherapy. Pathological markers for predicting outcomes after surgical resection and radiotherapy responsiveness are still lacking. Caveolin 1 has been associated with chemo- and radioresistance in various tumors, including non-small-cell lung cancer. Here, caveolin 1 expression was assessed in a series of 69 brain metastases from non-small-cell lung cancer and matched primary tumors to determine its role in predicting survival and radiotherapy responsiveness. Only caveolin 1 expression in brain metastasis was associated with poor prognosis and an increased risk of death (log rank test, p = 0.015). Moreover, in the younger patients (median age of <54 years), caveolin 1 expression neutralized the favorable effect of young age on survival compared with the older patients. Among the radiotherapy-treated patients, an increased risk of death was detected in the group with caveolin 1-positive brain metastasis (14 out of 22 patients, HR=6.839, 95% CI 1.849 to 25.301, Wald test p = 0.004). Overall, caveolin 1 expression in brain metastasis from non-small-cell lung cancer is independently predictive of worse outcome and radioresistance and could become an additional tool for personalized therapy in the critical subset of brain-metastatic non-small-cell lung cancer patients.

Afatinib in Treatment-Naive Patients With EGFR-Mutated Lung Adenocarcinoma With Brain Metastasis: A Case Series

Tyrosine kinase inhibitors (TKIs) of epidermal growth factor receptor (EGFR) were previously the standard first-line treatments for lung cancers with activating EGFR mutations. The first-generation reversible EGFR TKIs, gefitinib and erlotinib, demonstrated substantial efficacy in the treatment of brain metastases from EGFR-mutated lung adenocarcinoma. However, the efficacy of afatinib, the second-generation irreversible EGFR TKI, as the first-line treatment in lung adenocarcinoma patients with brain metastasis has yet to be evaluated.Here, we report cases of 3 patients who received afatinib alone as the first-line treatment in combination with whole-brain radiotherapy or following surgical resection of brain metastases. All 3 patients had EGFR L858R mutation. The first patient had lung adenocarcinoma with brain metastasis and no neurologic symptoms. After consultation, she received afatinib as a first-line treatment. Chest computed tomography and brain magnetic resonance imaging (MRI) showed partial response. The second patient had lung adenocarcinoma accompanied with a metastatic brain lesion associated with seizures. This patient received whole-brain radiotherapy and afatinib treatment following brain MRI and subsequently showed significant regression of the brain metastasis. The third patient had strabismus of the right eye, and brain MRI showed a single tumor at the cerebellar pontine angle. This patient underwent surgical resection of the tumor followed by afatinib treatment. He refused adjuvant radiotherapy after surgery for brain metastasis. The brain MRI showed no recurrent brain metastasis, and the patient had relatively less neurologic deficiency.This series of 3 cases indicate that afatinib may be an appropriate first-line treatment alternative in patients having lung adenocarcinoma with EGFR mutations. Further retrospective analyses and prospective clinical trials are required to substantiate the efficacy of afatinib in the treatment of brain metastases of lung adenocarcinoma.

Brain metastases: an overview

So far brain metastases represent a critical stage of a disease course and the frequency is increasing over the years. The treatment of brain metastases should be individualized for each patient: in case of single brain metastasis, surgery or radiosurgery should be considered as first options of treatment; in case of multiple lesions, whole-brain radiotherapy is the standard of care in association with systemic therapy or surgery/radiosurgery. Chemotherapy should be considered when surgery or radiation therapy are not possible. In the last decades, TKIs or monoclonal antibodies have shown increase in overall response rate and overall survival in Phase II-III trials. The aim of this paper is to make an overview of the current approaches in management of patients with brain metastases.

Advances in Imaging: Brain Tumors to Alzheimer's Disease

Professor Black and colleagues have been working to improve the quality and sensitivity of imaging in the early detection of conditions from brain tumors to Alzheimer's disease to enhance treatment protocols and patient management. Professor Black et al introduced nanoparticles to improve MRI imaging. These nanoparticles consist of poly (b-L- malic acid (PMLA)) conjugates with monoclonal antibodies ((mAbs)) and Gd-DOTA. These are known as MRI nano-imaging agents (NIA). Most importantly, they can penetrate the endothelial blood-brain barrier (BBB) to reach brain tumors (primary or metastasis). This is effective in cases of brain tumors or breast cancer or other cancers such as lung cancer and gastric cancer having HER2 and/or EGFR positive crossing BBB. By the covalent conjugation of MR contrast (NIA), the MRI virtual biopsy can differentiate brain tumors from infections or other brain pathological conditions. The brain's intrinsic natural fluorescence such as NADH, FAD, lipopigments and porphyrin in the brain tissue can be identified by using time resolved fluorescence spectroscopy (TRFS) which is operated through the use of ultra-short laser. TRFS produces various color bands to differentiate the tumor from normal brain tissue in real time and registers the data on a 3D map. This is significant, as this will provide a greatly improved assessment methodology of tissue type. Consequently, this will potentially result in shorter operation times as well as more satisfactory tumor removal. In the detection of Alzheimer disease, amyloid plaque is deposited in retina tissue (including the RGC, RNFL and inner plexiform layer) which can produce a fluorescence effect by using curcumin as a contrast. This is then shown by human retina amyloid imaging device. Immunotherapies with glatiramer acetate (GA) have been shown to reduce amyloid deposits in brain and retinal AB deposits in mice. The study of advanced imaging technology and techniques including NIA, TRFS and the detection of amyloid plaque in Alzheimer disease are very important approaches to create a new era for diagnostic and therapeutic management of brain tumors and other cancers (HER2 and/or EGFR positive). This pioneering work by Professor Black, and colleagues, gives rise to a new hope for cancer patients for targeted therapy and for immunotherapies in Alzheimer's disease.

MRI virtual biopsy and treatment of brain metastatic tumors with targeted nanobioconjugates: nanoclinic in the brain

Differential diagnosis of brain magnetic resonance imaging (MRI) enhancement(s) remains a significant problem, which may be difficult to resolve without biopsy, which can be often dangerous or even impossible. Such MRI enhancement(s) can result from metastasis of primary tumors such as lung or breast, radiation necrosis, infections, or a new primary brain tumor (glioma, meningioma). Neurological symptoms are often the same on initial presentation. To develop a more precise noninvasive MRI diagnostic method, we have engineered a new class of poly(β-l-malic acid) polymeric nanoimaging agents (NIAs). The NIAs carrying attached MRI tracer are able to pass through the blood-brain barrier (BBB) and specifically target cancer cells for efficient imaging. A qualitative/quantitative "MRI virtual biopsy" method is based on a nanoconjugate carrying MRI contrast agent gadolinium-DOTA and antibodies recognizing tumor-specific markers and extravasating through the BBB. In newly developed double tumor xenogeneic mouse models of brain metastasis this noninvasive method allowed differential diagnosis of HER2- and EGFR-expressing brain tumors. After MRI diagnosis, breast and lung cancer brain metastases were successfully treated with similar tumor-targeted nanoconjugates carrying molecular inhibitors of EGFR or HER2 instead of imaging contrast agent. The treatment resulted in a significant increase in animal survival and markedly reduced immunostaining for several cancer stem cell markers. Novel NIAs could be useful for brain diagnostic MRI in the clinic without currently performed brain biopsies. This technology shows promise for differential MRI diagnosis and treatment of brain metastases and other pathologies when biopsies are difficult to perform.

Enhanced antitumor effects of the BRBP1 compound peptide BRBP1-TAT-KLA on human brain metastatic breast cancer

Novel molecularly targeted agents that block the development and metastasis of human brain metastatic breast cancer hold great promise for their translational value. In this study, we constructed a novel targeting composite peptide BRBP1-TAT-KLA comprising of three elements: a brain metastatic breast carcinoma cell (231-BR)-binding peptide BRBP1, a cell penetrating peptide TAT, and a proapoptotic peptide KLA. This composite peptide efficiently internalized in 231-BR cells and consequently induced mitochondrial damage and cellular apoptosis. Exposure of 231-BR cells to BRBP1-TAT-KLA significantly decreased cell viability and increased apoptosis compared with the cells treated with the control peptides. In vivo relevance of these findings was further corroborated in the 231-BR tumor-bearing mice that demonstrated significantly delayed tumor development and metastasis following administration of BRBP1-TAT-KLA compared with those treated with TAT-KLA alone. Interestingly, BRBP1-TAT-KLA inhibited the formation of both large and micro-metastases, while TAT-KLA alone failed to significantly reduce micro-metastases in the breast cancer brain metastasis mice. BRBP1-TAT-KLA selectively homed to the tumors in vivo where it induced cellular apoptosis without significant toxicity on non-tumor tissues. Our findings therefore demonstrated the enhanced antitumor effects of the BRBP1 compound peptide BRBP1-TAT-KLA, providing insights toward development of a potential therapeutic strategy for brain metastatic breast cancer.

Stereotactic radiosurgery for multiple brain metastases

Stereotactic radiosurgery (SRS) alone has become one of the treatment options for patients with 1-4 metastases as the detrimental effects of whole brain radiation therapy on neurocognition and quality of life are becoming well known. Multiple randomized control trials also failed to show overall survival benefit of adding whole brain radiation therapy to SRS. However, the role of SRS in multiple brain metastases, especially those with ≥ 4 tumors, remains controversial. The literature is emerging, and the limited evidence suggests that the local control benefit is independent of the number of metastases, and that patients with more than four brain metastases have similar overall survival compared to those with 2-4 tumors. This review aims at summarizing the current evidence of SRS for multiple brain metastases, divided into limited (2-3) and multiple (≥ 4) lesions. It also reviews the technical aspects and cost-effectiveness of SRS.

New protein kinase inhibitors in breast cancer: afatinib and neratinib

INTRODUCTION

Human epidermal growth factor receptor (HER) 2 is overexpressed in 20 - 25% of breast cancers, and has historically been a poor prognostic marker. The introduction of trastuzumab, the first fully humanized monoclonal antibody targeting HER2, has drastically changed the outcomes of metastatic breast cancers. However, despite initial response, most patients develop resistance. Recent data suggest that strategies targeting more than one member of HER family may circumvent trastuzumab resistance and confer synergistic effects.

AREAS COVERED

Following a literature search on PubMed, national meetings and clinicaltrials.gov using 'afatinib', 'neratinib', 'HER2' and 'breast cancer' as keywords, we critically analyzed the different HER2-targeted therapies for their drug development and evidence-based therapeutic strategies. Afatinib and neratinib, two second-generation tyrosine kinase inhibitors (TKIs) that irreversibly inhibit more than one HER family member, are being actively investigated in clinical trials either as monotherapy or in combination. We reviewed the efficacy and optimal use of these agents in various settings, such as systemic therapy for advanced breast cancer including brain metastases, and neoadjuvant therapy in early-stage breast cancer.

EXPERT OPINION

HER2-targeted therapies have been widely used and greatly improved the outcome of HER2-positive breast cancer. Despite the accelerated advancement in recent years, several crucial questions remain unanswered, such as how to treat a prior resistance or affect a sanctuary site, that is, CNS metastasis. The novel next-generation TKIs, afatinib and neratinib, were rationally designed to overcome the resistance by targeting multiple HER family members and irreversibly binding the targets. In spite of the encouraging results of the afatinib and neratinib monotherapies, they have not been proven more efficacious in the combination therapies yet, even though multicenter international trials are still ongoing. The key tasks in the future are to study resistance pathways, design novel strategies to more efficiently test combinations for synergistic effects and identify biomarkers and novel imaging tools to guide individualized therapies.