Survival of patients with metastatic melanoma and brain metastases in the era of MAP-kinase inhibitors and immunologic checkpoint blockade antibodies: A systematic review

The treatment of advanced melanoma: Current approaches and new challenges

In recent years, advances in melanoma treatment have renewed patient hope. This comprehensive review emphasizes the evolving treatment landscape, particularly highlighting first-line strategies and the interplay between immune-checkpoint inhibitors (ICIs) and targeted therapies. Ipilimumab plus nivolumab has achieved the best median overall survival, exceeding 70 months. However, the introduction of new ICIs, like relatlimab, has added complexity to first-line therapy decisions. Our aim is to guide clinicians in making personalized treatment decisions. Various features, including brain metastases, PD-L1 expression, BRAF mutation, performance status, and prior adjuvant therapy, significantly impact the direction of advanced melanoma treatment. We also provide the latest insights into the treatment of rare melanoma subtypes, such as uveal melanoma, where tebentafusp has shown promising improvements in overall survival for metastatic uveal melanoma patients. This review provides invaluable insights for clinicians, enabling informed treatment choices and deepening our understanding of the multifaceted challenges associated with advanced melanoma management.

Outcomes in patients with BRAFV600-mutated melanoma and brain metastases at baseline treated with dabrafenib plus trametinib

BACKGROUND

Brain metastases (BM) and lactate dehydrogenase (LDH) levels above the upper limit of normal (ULN) are associated with poor prognosis in patients with melanoma. Although treatment with the BRAF inhibitor dabrafenib and the MEK inhibitor trametinib have demonstrated long-term clinical benefit in patients with melanoma, data on their efficacy in patients with BM are limited.

METHODS

DESCRIBE Italy is an observational, retrospective, real-world study evaluating dabrafenib plus trametinib in 499 patients with BRAFV600-mutant stage III unresectable or stage IV melanoma from various sites across Italy. Here, we analyzed the clinical outcomes for the subgroup of patients receiving first-line treatment and presenting with BM at diagnosis and assessed the impact of predictive factors such as LDH levels and the presence of other metastases on median progression-free survival (mPFS).

RESULTS

Overall, 325 evaluable patients were on first-line therapy and are the focus of this analysis; of these, 76 patients (23.4%) had BM at baseline. mPFS was lower for patients with BM at baseline compared with overall patients (8.7 months vs 9.3 months, respectively). Patients with BM at diagnosis and LDH >ULN had a considerably shorter mPFS compared with patients with LDH ⩽ULN (5.3 months vs 9.9 months, respectively). mPFS was noticeably longer for patients with cerebral metastases only compared with patients with cerebral and other metastases (15.0 months vs 8.7 months, respectively).

CONCLUSIONS

Dabrafenib plus trametinib showed effectiveness in a real-world population of patients with advanced BRAFV600-mutated melanoma and BM at baseline, supporting its use in this population with poor outcomes.

Estimating survival in patients with melanoma brain metastases: prognostic value of lactate dehydrogenase

Patients with melanoma brain metastases (MBM) have poor prognosis, albeit advances in locoregional and systemic treatments. The melanoma-specific Graded Prognostic Assessment (GPA) effectively stratifies survival for patients with MBM. Nevertheless, lactate dehydrogenase (LDH), a well known prognostic factor for patients with melanoma, is not represented in the GPA scores and might add prognostic information for patients with MBM. In this study, 150 consecutive patients with MBM were retrospectively analyzed with the aim of evaluating independent prognostic factors for MBM patients, including LDH. Furthermore, we implemented a disease-specific prognostic score and estimated survival according to treatment modalities. On the basis of multivariable Cox regression analyses, six prognostic factors (age, BRAF status, number of MBM, number of extracranial metastatic sites, performance status, and LDH level) resulted statistically significant in terms of survival and were combined in a prognostic score to stratify patients in distinct prognostic groups ( P  < 0.0001). Among treatment modalities, a multimodal approach with stereotactic radiosurgery or neurosurgery associated with systemic therapy showed the best outcome (median overall survival: 12.32 months, 95% confidence interval, 7.92-25.30). This is the first study to demonstrate that LDH has independent prognostic value for patients with MBM and might be used to improve prognostic stratification, albeit external validation is mandatory. Survival of patients with MBM is affected by both disease-specific risk factors and treatment modalities, with locoregional treatments associated with better outcomes.

Health-state utilities in long-term advanced melanoma survivors comparable with the general population

BACKGROUND

Checkpoint inhibitors have been shown to substantially improve the survival of patients with advanced melanoma. With this growing group of survivors treated with immunotherapies, assessing their health-state utilities is essential and can be used for the calculation of quality-adjusted life years and for cost-effectiveness analyses. Therefore, we evaluated the health-state utilities in long-term advanced melanoma survivors.

METHODS

Health-state utilities were evaluated in a cohort of advanced melanoma survivors 24-36 months (N = 37) and 36-plus months (N = 47) post-ipilimumab monotherapy. In addition, the health-state utilities of the 24-36 months survivor group were assessed longitudinally, and utilities of the combined survival groups (N = 84) were compared with a matched control population (N = 168). The EQ-5D was used to generate health-state utility values, and quality-of-life questionnaires were used to establish correlations and influencing factors of utility scores.

RESULTS

Health-state utility scores were similar between the 24-36 months'- and the 36-plus months' survival group (0.81 vs 0.86; p = .22). In survivors, lower utility scores were associated with symptoms of depression (β = - .82, p = .022) and fatigue burden (β = - .29, p = .007). Utility scores did not significantly change after 24-36 months of survival, and the utilities of survivors were comparable to the matched control population (0.84 vs 0.87; p = .07).

DISCUSSION

Our results show that long-term advanced melanoma survivors treated with ipilimumab monotherapy experience relatively stable and high health-state utility scores.

Systematic in vitro analysis of therapy resistance in glioblastoma cell lines by integration of clonogenic survival data with multi-level molecular data

Despite intensive basic scientific, translational, and clinical efforts in the last decades, glioblastoma remains a devastating disease with a highly dismal prognosis. Apart from the implementation of temozolomide into the clinical routine, novel treatment approaches have largely failed, emphasizing the need for systematic examination of glioblastoma therapy resistance in order to identify major drivers and thus, potential vulnerabilities for therapeutic intervention. Recently, we provided proof-of-concept for the systematic identification of combined modality radiochemotherapy treatment vulnerabilities via integration of clonogenic survival data upon radio(chemo)therapy with low-density transcriptomic profiling data in a panel of established human glioblastoma cell lines. Here, we expand this approach to multiple molecular levels, including genomic copy number, spectral karyotyping, DNA methylation, and transcriptome data. Correlation of transcriptome data with inherent therapy resistance on the single gene level yielded several candidates that were so far underappreciated in this context and for which clinically approved drugs are readily available, such as the androgen receptor (AR). Gene set enrichment analyses confirmed these results, and identified additional gene sets, including reactive oxygen species detoxification, mammalian target of rapamycin complex 1 (MTORC1) signaling, and ferroptosis/autophagy-related regulatory circuits to be associated with inherent therapy resistance in glioblastoma cells. To identify pharmacologically accessible genes within those gene sets, leading edge analyses were performed yielding candidates with functions in thioredoxin/peroxiredoxin metabolism, glutathione synthesis, chaperoning of proteins, prolyl hydroxylation, proteasome function, and DNA synthesis/repair. Our study thus confirms previously nominated targets for mechanism-based multi-modal glioblastoma therapy, provides proof-of-concept for this workflow of multi-level data integration, and identifies novel candidates for which pharmacological inhibitors are readily available and whose targeting in combination with radio(chemo)therapy deserves further examination. In addition, our study also reveals that the presented workflow requires mRNA expression data, rather than genomic copy number or DNA methylation data, since no stringent correlation between these data levels could be observed. Finally, the data sets generated in the present study, including functional and multi-level molecular data of commonly used glioblastoma cell lines, represent a valuable toolbox for other researchers in the field of glioblastoma therapy resistance.

Efficacy of immunotherapy for melanoma brain metastases in patients with concurrent corticosteroid exposure

Aim: Immune checkpoint inhibitor (ICI) efficacy is undefined for melanoma brain metastases (MBM) with concurrent corticosteroid exposure. Materials & methods: We retrospectively evaluated patients with untreated MBM who received corticosteroids (≥1.5 mg dexamethasone equivalent) within 30 days of ICI. mRECIST criteria and Kaplan-Meier methods defined intracranial progression-free survival (iPFS). The lesion size-response association was evaluated with repeated measures modeling. Results: A total of 109 MBM were evaluated. The patient level intracranial response rate was 41%. Median iPFS was 2.3 months and overall survival was 13.4 months. Larger lesions were more likely to progress, with diameter >2.05 cm most predictive of progression (OR: 18.9; 95% CI: 2.6-139.5; p = 0.004). There was no difference in iPFS with steroid exposure pre- versus post-ICI initiation. Conclusion: In the largest reported ICI+corticosteroid cohort, we identify size dependent MBM response.

Identification and validation of a ferroptosis-related gene signature for predicting survival in skin cutaneous melanoma

PURPOSE

Ferroptosis plays a crucial role in the initiation and progression of melanoma. This study developed a robust signature with ferroptosis-related genes (FRGs) and assessed the ability of this signature to predict OS in patients with skin cutaneous melanoma (SKCM).

METHODS

RNA-sequencing data and clinical information of melanoma patients were extracted from TCGA, GEO, and GTEx. Univariate, multivariate, and LASSO regression analyses were conducted to identify the gene signature. A 10 FRG signature was an independent and strong predictor of survival. The predictive performance was assessed using ROC curve. The functions of this gene signature were assessed by GO and KEGG analysis. The statuses of low-risk and high-risk groups according to the gene signature were compared by GSEA. In addition, we investigated the possible relationship of FRGs with immunotherapy efficacy.

RESULTS

A prognostic signature with 10 FRGs (CYBB, IFNG, FBXW7, ARNTL, PROM2, GPX2, JDP2, SLC7A5, TUBE1, and HAMP) was identified by Cox regression analysis. This signature had a higher prediction efficiency than clinicopathological features (AUC = 0.70). The enrichment analyses of DEGs indicated that ferroptosis-related immune pathways were largely enriched. Furthermore, GSEA showed that ferroptosis was associated with immunosuppression in the high-risk group. Finally, immune checkpoints such as PDCD-1 (PD-1), CTLA4, CD274 (PD-L1), and LAG3 were also differential expression in two risk groups.

CONCLUSIONS

The 10 FRGs signature were a strong predictor of OS in SKCM and could be used to predict therapeutic targets for melanoma.

The role of stereotactic radiotherapy in addition to immunotherapy in the management of melanoma brain metastases: results of a systematic review

Aim of this study was to systematically review the literature to assess efficacy and safety of stereotactic radiotherapy (SRT) in combination with immunotherapy for the treatment of melanoma brain metastases (MBM). The literature was searched using PubMed, Scopus, and Embase. Studies comparing SRT plus immunotherapy versus SRT or immunotherapy alone were deemed eligible for inclusion. Two studies showed improved overall survival after SRT plus immunotherapy in melanoma cancer patients with brain metastases. Three studies reported data on LC and DFS showing as SRT plus immunotherapy did not improve local control and DFS rates. G3-G4 toxicity was reported in only one study (20% in the SRT plus immunotherapy group versus 23% in the immunotherapy group). Despite SRT plus concurrent immunotherapy seems associated with possible survival advantage and low ≥ G3 late toxicity rates, the quality of evidence is very low. Therefore, in patients with brain metastases from melanoma, SRT plus immunotherapy should be evaluated on an individual basis after discussion by a multidisciplinary team.

Comprehensive summary and retrospective evaluation of prognostic scores for patients with newly diagnosed brain metastases treated with upfront radiosurgery in a modern patient collective

BACKGROUND

Numerous prognostic scores (PS) for patients with brain metastases (BM) have been developed. Recently, PS based on laboratory parameters were introduced to better predict overall survival (OS). A comprehensive comparison of the wide range of scores in a modern patient collective is still missing.

MATERIALS AND METHODS

Twelve PS considering clinical parameters only at the time of BM diagnosis were calculated for 470 patients receiving upfront SRS between January 2014 and March 2020. In a subcohort of 310 patients where a full laboratory dataset was available five additional prognostic scores were compared. Restricted mean survival time (RMST), partial likelihood and c-index were calculated as metrics for performance evaluation. Univariable and multivariable analysis were used to identify prognostic factors for OS.

RESULTS

The median OS of the whole cohort was 15.8 months (95% C.I.: 13.4-20.1). All prognostic scores performed well in separating patients into different prognostic groups. RPA achieved the highest c-index, whereas GGS achieved highest partial likelihood with evaluation in the total cohort. With incorporation of the laboratory scores the recently suggested EC-GPA achieved highest c-index and highest partial likelihood. A prognostic score solely based on the assessment of performance status achieved considerable high performance as either 3- or 4-tiered score. Multivariable analysis revealed performance status, systemic disease status and laboratory parameters to be significantly associated with OS among variates included in prognostic scores.

CONCLUSION

Although recent PS incorporating laboratory parameters show convincing performance in predicting overall survival, older scores relying on clinical parameters only are still valid and appealing as they are easier to calculate, and as overall performance is almost equal. Moreover, a score just based on performance status is not significantly inferior and should at least be assessed for informed decision making.

Perspectives for Combining Viral Oncolysis With Additional Immunotherapies for the Treatment of Melanoma

Melanoma is the deadliest type of skin cancer with steadily increasing incidence worldwide during the last few decades. In addition to its tumor associated antigens (TAAs), melanoma has a high mutation rate compared to other tumors, which promotes the appearance of tumor specific antigens (TSAs) as well as increased lymphocytic infiltration, inviting the use of therapeutic tools that evoke new or restore pre-existing immune responses. Innovative therapeutic proposals, such as immune checkpoint inhibitors (ICIs), have emerged as effective options for melanoma. However, a significant portion of these patients relapse and become refractory to treatment. Likewise, strategies using viral vectors, replicative or not, have garnered confidence and approval by different regulatory agencies around the world. It is possible that further success of immune therapies against melanoma will come from synergistic combinations of different approaches. In this review we outline molecular features inherent to melanoma and how this supports the use of viral oncolysis and immunotherapies when used as monotherapies or in combination.

Employing CRISPR-Cas9 to Generate CD133 Synthetic Lethal Melanoma Stem Cells

Malignant melanoma is a lethal skin cancer containing melanoma-initiating cells (MIC) implicated in tumorigenesis, invasion, and drug resistance, and is characterized by the elevated expression of stem cell markers, including CD133. The siRNA knockdown of CD133 enhances apoptosis induced by the MEK inhibitor trametinib in melanoma cells. This study investigates the underlying mechanisms of CD133's anti-apoptotic activity in patient-derived BAKP and POT cells, harboring difficult-to-treat NRASQ61K and NRASQ61R drivers, after CRISPR-Cas9 CD133 knockout or Dox-inducible expression of CD133. MACS-sorted CD133(+) BAKP cells were conditionally reprogrammed to derive BAKR cells with sustained CD133 expression and MIC features. Compared to BAKP, CD133(+) BAKR exhibit increased cell survival and reduced apoptosis in response to trametinib or the chemotherapeutic dacarbazine (DTIC). CRISPR-Cas9-mediated CD133 knockout in BAKR cells (BAKR-KO) re-sensitized cells to trametinib. CD133 knockout in BAKP and POT cells increased trametinib-induced apoptosis by reducing anti-apoptotic BCL-xL, p-AKT, and p-BAD and increasing pro-apoptotic BAX. Conversely, Dox-induced CD133 expression diminished apoptosis in both trametinib-treated cell lines, coincident with elevated p-AKT, p-BAD, BCL-2, and BCL-xL and decreased activation of BAX and caspases-3 and -9. AKT1/2 siRNA knockdown or inhibition of BCL-2 family members with navitoclax (ABT-263) in BAKP-KO cells further enhanced caspase-mediated apoptotic PARP cleavage. CD133 may therefore activate a survival pathway where (1) increased AKT phosphorylation and activation induces (2) BAD phosphorylation and inactivation, (3) decreases BAX activation, and (4) reduces caspases-3 and -9 activity and caspase-mediated PARP cleavage, leading to apoptosis suppression and drug resistance in melanoma. Targeting nodes of the CD133, AKT, or BCL-2 survival pathways with trametinib highlights the potential for combination therapies for NRAS-mutant melanoma stem cells for the development of more effective treatments for patients with high-risk melanoma.

Recommended first-line management of brain metastases from melanoma: A multicenter survey of clinical practice

BACKGROUND

Radiotherapy (RT) and surgery (Sx) are effective in treating brain metastases. However, immune checkpoint inhibitors (ICI) have shown activity against asymptomatic melanoma brain metastases (MBM). BRAF/MEK inhibitors can be used to treat BRAF V600 mutation positive (BRAF+) MBM.

METHOD

We conducted an international survey among experts from medical oncology (MO), clinical oncology (CO), radiation oncology (RO), and neurosurgery (NS) about treatment recommendations for patients with asymptomatic BRAF+ or BRAF mutation negative (BRAF-) MBM. Eighteen specific clinical scenarios were presented and a total of 267 responses were collected. Answers were grouped and compared using Fisher's exact test.

RESULTS

In most MBM scenarios, survey respondents, regardless of specialty, favored RT in addition to systemic therapy. However, for patients with BRAF+ MBM, MO and CO were significantly more likely than RO and NS to recommend BRAF/MEK inhibitors alone, without the addition of RT, including the majority of MO (51%) for patients with 1-3 MBM, all <2cm. Likewise, for BRAF- MBM, MO and CO more commonly recommended single or dual agent ICI only and dual agent ICI therapy alone was the most common recommendation from MO or CO for MBM <2cm. When at least 1 of 3 MBM (BRAF+ or BRAF-) was >2cm, upfront Sx was recommended by all groups with the exception that MO and RO recommended RT for BRAF- MBM.

CONCLUSIONS

In most clinical settings involving asymptomatic MBM, experts recommended RT in addition to systemic therapy. However, recommendations varied significantly according to specialty, with MO and CO more commonly recommending dual systemic therapy alone for up to 9 BRAF- MBM <2cm.

Detection of clinical progression through plasma ctDNA in metastatic melanoma patients: a comparison to radiological progression

BACKGROUND

The validity of circulating tumour DNA (ctDNA) as an indicator of disease progression compared to medical imaging in patients with metastatic melanoma requires detailed evaluation.

METHODS

Here, we carried out a retrospective ctDNA analysis of 108 plasma samples collected at the time of disease progression. We also analysed a validation cohort of 66 metastatic melanoma patients monitored prospectively after response to systemic therapy.

RESULTS

ctDNA was detected in 62% of patients at the time of disease progression. For 67 patients that responded to treatment, the mean ctDNA level at progressive disease was significantly higher than at the time of response (P < 0.0001). However, only 30 of these 67 (45%) patients had a statistically significant increase in ctDNA by Poisson test. A validation cohort of 66 metastatic melanoma patients monitored prospectively indicated a 56% detection rate of ctDNA at progression, with only two cases showing increased ctDNA prior to radiological progression. Finally, a correlation between ctDNA levels and metabolic tumour burden was only observed in treatment naïve patients but not at the time of progression in a subgroup of patients failing BRAF inhibition (N = 15).

CONCLUSIONS

These results highlight the low efficacy of ctDNA to detect disease progression in melanoma when compared mainly to standard positron emission tomography imaging.

Central Nervous System Metastases

The proportion of patients developing central nervous system (CNS) metastasis is increasing. Most are identified once symptomatic. Surgical resection is indicated for solitary or symptomatic brain metastases, separation surgery for compressive radioresistant spinal metastases, and instrumentation for unstable spinal lesions. Surgical biopsies are performed when histological diagnoses are required. Stereotactic radiosurgery is an option for limited small brain metastases and radioresistant spinal metastases. Whole-brain radiotherapy is reserved for extensive brain metastases and leptomeningeal disease with approaches to reduce cognitive side effects. Radiosensitive and inoperable spinal metastases typically receive external beam radiotherapy. Systemic therapy is increasingly being utilized for CNS metastases.

Melanoma Metastases to the Adrenal Gland Are Highly Resistant to Immune Checkpoint Inhibitors

BACKGROUND

Adrenal gland metastases (AGMs) are common in advanced-stage melanoma, occurring in up to 50% of patients. The introduction of immune checkpoint inhibitors (ICIs) has markedly altered the outcome of patients with melanoma. However, despite significant successes, anecdotal evidence has suggested that treatment responses in AGMs are significantly lower than in other metastatic sites. We sought to investigate whether having an AGM is associated with altered outcomes and whether ICI responses are dampened in the adrenal glands.

PATIENTS AND METHODS

We retrospectively compared ICI responses and overall survival (OS) in 68 patients with melanoma who were diagnosed with an AGM and a control group of 100 patients without AGMs at a single institution. Response was determined using RECIST 1.1. OS was calculated from time of ICI initiation, anti-PD-1 initiation, initial melanoma diagnosis, and stage IV disease diagnosis. Tumor-infiltrating immune cells were characterized in 9 resected AGMs using immunohistochemical analysis.

RESULTS

Response rates of AGMs were significantly lower compared with other metastatic sites in patients with AGMs (16% vs 22%) and compared with those without AGMs (55%). Patients with AGMs also had significantly lower median OS compared with those without AGMs (3.1 years vs not reached, respectively). We further observed that despite this, AGMs exhibited high levels of tumor-infiltrating immune cells.

CONCLUSIONS

In this cohort of patients with melanoma, those diagnosed with an AGM had lower ICI response rates and OS. These results suggest that tissue-specific microenvironments of AGMs present unique challenges that may require novel, adrenal gland-directed therapies or surgical resection.

Prognostic Value of ctDNA Mutation in Melanoma: A Meta-Analysis

PURPOSE

Melanoma is the most aggressive form of skin cancer. Circulating tumor DNA (ctDNA) is a diagnostic and prognostic marker of melanoma. However, whether ctDNA mutations can independently predict survival remains controversial. This meta-analysis assessed the prognostic value of the presence or change in ctDNA mutations in melanoma patients.

METHODS

We identified studies from the PubMed, EMBASE, Web of Science, and Cochrane databases. We estimated the combined hazard ratios (HRs) for overall survival (OS) and progression-free survival (PFS) using either fixed-effect or random-effect models based on heterogeneity.

RESULTS

Sixteen studies including 1,781 patients were included. Both baseline and posttreatment detectable ctDNA were associated with poor OS (baseline detectable vs. undetectable, pooled HR = 1.97, 95% CI = 1.64-2.36, P < 0.00001; baseline undetectable vs. detectable, pooled HR = 0.19, 95% CI = 0.11-0.36, P < 0.00001; posttreatment detectable vs. undetectable, pooled HR = 2.36, 95% CI = 1.30-4.28, P=0.005). For PFS, baseline detectable ctDNA may be associated with adverse PFS (baseline detectable vs. undetectable, pooled HR = 1.41, 95% CI = 0.84-2.37, P=0.19; baseline undetectable vs. detectable, pooled HR = 0.43, 95% CI = 0.19-0.95, P=0.04) and baseline high ctDNA and increased ctDNA were significantly associated with adverse PFS (baseline high vs. low/undetectable, pooled HR = 3.29, 95% CI = 1.73-6.25, P=0.0003; increase vs. decrease, pooled HR = 4.48, 95% CI = 2.45-8.17, P < 0.00001). The baseline BRAFV600 ctDNA mutation-positive group was significantly associated with adverse OS compared with the baseline ctDNA-negative group (pooled HR = 1.90, 95% CI = 1.58-2.29, P < 0.00001). There were no significant differences in PFS between the baseline BRAFV600 ctDNA mutation-detectable group and the undetectable group (pooled HR = 1.02, 95% CI = 0.72-1.44, P=0.92).

CONCLUSION

The presence or elevation of ctDNA mutation or BRAFV600 ctDNA mutation was significantly associated with worse prognosis in melanoma patients.

Melanoma brain metastases in Ireland: surgical and systemic considerations

BACKGROUND

Cerebral metastases is a common complication in patients with melanoma. There is a paucity of information in the Republic of Ireland regarding the factors associated with melanoma brain metastases (MBM).

METHODS

Patients diagnosed with melanoma brain metastases in Ireland were retrospectively identified in Beaumont Hospital between 1999 and 2018. Patient demographics; age at diagnosis of primary melanoma, age at detection of MBM, year of detection of MBM, anatomical location of primary melanoma, BRAF mutation analysis and the number of metastases were investigated. Follow-up data were also derived, including overall survival.

RESULTS

There has being a 158% increase in the incidence of primary melanoma from 1999 compared to 2016. Over the same time period 128 patients with melanoma brain metastases were diagnosed. There was a significant male predominance (n = 77/128; 60%; p < 0.0001). BRAF mutation and leptomeningeal disease were independent prognostic factors in our cohort with a median survival 8 months and 0.5 months, respectively.

CONCLUSIONS

Male predominance, leptomeningeal disease and BRAF mutation represent important considerations in this population group. The results of this study add to our knowledge concerning outcomes in melanoma brain metastases and may be useful in clinical planning and future treatments.

Efficacy of BRAF Inhibitors in Combination With Stereotactic Radiosurgery for the Treatment of Melanoma Brain Metastases: A Systematic Review and Meta-Analysis

Background

BRAF inhibitors have improved the outcome for patients with BRAF mutant metastatic melanoma and have shown intracranial responses in melanoma brain metastases. Stereotactic radiosurgery (SRS) is being used as a local treatment for melanoma brain metastasis (MBM) with better local control and survival. We searched for studies comparing the combination of two treatments with SRS alone to detect any clinical evidence of synergism.

Materials and Methods

PubMed, EMBASE, Medline, and Cochrane library were searched until May 2020 for studies with desired comparative outcomes. Outcomes of interest that were obtained for meta-analysis included survival as the primary, and local control as the secondary outcome.

Results

A total of eight studies involving 976 patients with MBM were selected. Survival was significantly improved for patients receiving BRAF inhibitor plus SRS in comparison to SRS alone as assessed from the time of SRS induction (SRS survival: hazard ratio [HR] 0.67 [0.58–0.79], p <0.00001), from the time of brain metastasis diagnosis (BM survival: HR 0.65 [0.54, 0.78], p < 0.00001), or from the time of primary diagnosis (PD survival: HR 0.74 [0.57–0.95], p = 0.02). Dual therapy was also associated with improved local control, indicating an additive effect of the two treatments (HR 0.53 [0.31–0.93], p=0.03). Intracranial hemorrhage was higher in patients receiving BRAF inhibitors plus SRS than in those receiving SRS alone (OR, 3.16 [1.43–6.96], p = 0.004).

Conclusions

BRAF inhibitors in conjunction with SRS as local treatment appear to be efficacious. Local brain control and survival improved in patients with MBM receiving dual therapy. Safety assessment would need to be elucidated further as the incidence of intracranial hemorrhage was increased.

Brain Radiation Induced Extracranial Abscopal Effects in Metastatic Melanoma

Historically, the brain has been viewed as a specialized neurovascular inert organ with a distinctive immune privilege. Therefore, radiation-induced extracranial abscopal effects would be considered an unusual phenomenon due to the difficulty of the immunogenic signaling molecules to travel across the blood-brain barrier (BBB). However, it is now possible that localized central nervous system radiation has the ability to disrupt the structural integrity of the BBB and increase its endothelial permeability allowing the free passage of immunogenic responses between the intracranial and extracranial compartments. Thus, the nascent tumor-associated antigens produced by localized brain radiation can travel across the BBB into the rest of the body to modulate the immune system and induce extracranial abscopal effects. In clinical practice, localized brain radiation therapy-induced extracranial abscopal effects are a rarely seen phenomenon in metastatic melanoma and other advanced cancers. In this article, we provide a detailed overview of the current state of knowledge and clinical experience of central nervous system radiation-induced extracranial abscopal effects in patients with malignant melanoma. Emerging data from a small number of case reports and cohort studies of various malignancies has significantly altered our earlier understanding of this process by revealing that the brain is neither isolated nor passive in its interactions with the body's immune system. In addition, these studies provide clinical evidence that the brain is capable of interacting actively with the extracranial peripheral immune system. Thus, localized radiation treatment to 1 or more locations of brain metastases can induce extracranial abscopal responses. Collectively, these findings clearly demonstrate that localized brain radiation therapy-induced abscopal effects traverses the BBB and trigger tumor regression in the nonirradiated extracranial locations.

Circulating tumour DNA and melanoma survival: A systematic literature review and meta-analysis

We reviewed and meta-analysed the available evidence (until December 2019) about circulating tumour DNA (ctDNA) levels and melanoma patients survival. We included twenty-six studies (>2000 patients overall), which included mostly stage III-IV cutaneous melanoma patients and differed widely in terms of systemic therapy received and somatic mutations that were searched. Patients with detectable ctDNA before treatment had worse progression-free survival (PFS) (summary hazard ratio (SHR) 2.47, 95 % confidence intervals (CI) 1.85-3.29) and overall survival (OS) (SHR 2.98, 95 % CI 2.26-3.92), with no difference by tumour stage. ctDNA detectability during follow-up was associated with poorer PFS (SHR 4.27, 95 %CI 2.75-6.63) and OS (SHR 3.91, 95 %CI 1.97-7.78); in the latter case, the association was stronger (p = 0.01) for stage IV vs. III melanomas. Between-estimates heterogeneity was low for all pooled estimates. ctDNA is a strong prognostic biomarker for advanced-stage melanoma patients, robust across tumour (e.g. genomic profile) and patients (e.g. systemic therapy) characteristics.

Drug Development for Central Nervous System Diseases Using In vitro Blood-brain Barrier Models and Drug Repositioning

An important goal of biomedical research is to translate basic research findings into practical clinical implementation. Despite the advances in the technology used in drug discovery, the development of drugs for central nervous system diseases remains challenging. The failure rate for new drugs targeting important central nervous system diseases is high compared to most other areas of drug discovery. The main reason for the failure is the poor penetration efficacy across the blood-brain barrier. The blood-brain barrier represents the bottleneck in central nervous system drug development and is the most important factor limiting the future growth of neurotherapeutics. Meanwhile, drug repositioning has been becoming increasingly popular and it seems a promising field in central nervous system drug development. In vitro blood-brain barrier models with high predictability are expected for drug development and drug repositioning. In this review, the recent progress of in vitro BBB models and the drug repositioning for central nervous system diseases will be discussed.

Identification of the origin of brain metastases based on the relative methylation orderings of CpG sites

Accurate diagnosis of the origin of brain metastases (BMs) is crucial for tailoring an effective therapy to improve patients' prognosis. BMs of unknown origin account for approximately 2-14% of patients with BMs. Hence, the aim of this study was to identify the original cancer type of BMs based on their DNA methylation profiles. The DNA methylation profiles of glioma (GM), BM, and seven other types of primary cancers were collected. In comparison with GM, the reversal CpG site pairs were identified for each of the seven other types of primary cancers based on the within-sample relative methylation orderings (RMOs) of the CpG sites. Then, using the reversal CpG site pairs, GMs were distinguished from BMs and the seven other types of primary cancers. All 61 of the GM samples were correctly identified as GM. The cancer type was also identified for the non-GM samples. For the seven other types of primary cancers, greater than 93% of samples of each cancer type were correctly identified as their corresponding cancer type, except for breast cancer, which had an 88% accuracy. For 133 BM samples, 132 BM samples were identified as non-GM, and 95% of the 133 BM samples were correctly classified into their corresponding original cancer types. The RMO-based method can accurately identify the origin of BMs, which is important for precision treatment.

Chemotherapy for the Management of Cerebral Metastases

Chemotherapy has played a minor role as adjuvant therapy in treatment of cerebral metastases from solid cancers. The blood-brain barrier and cerebral metastases' considerable machinery of self-preservation have been significant obstacles to delivery and efficacy of chemotherapy. However, several methods intended to surmount these challenges have arisen alongside advent of technology and with the development of targeted molecular therapies. Focused ultrasound and molecular Trojan horses represent two such novel means of increasing permeability of the blood-brain barrier to effector agents. Published data on efficacy of these targeted therapies remain mostly restricted to retrospective studies and phase II prospective clinical trials.

Survival outcomes in an older US population with advanced melanoma and central nervous system metastases: SEER-Medicare analysis

BACKGROUND

Central nervous system (CNS) metastasis is common in advanced melanoma patients. New treatment options have improved overall prognosis, but information is lacking for patients with CNS metastases. We investigated treatment patterns and survival outcomes in older melanoma patients with and without CNS metastases.

METHODS

A retrospective analysis of SEER-Medicare, a population-based linked database, was undertaken in patients aged > 65 years with advanced melanoma diagnosed from 2004 to 2011 and followed until 2013.

RESULTS

A total of 2522 patients were included. CNS metastases were present in 24.8% of patients at initial metastatic diagnosis; 16.5% developed CNS metastases during follow-up. Chemotherapy was the most common treatment regardless of CNS metastases. Overall survival (OS) was better for patients without CNS metastases (median, 9.5 months; 95% confidence interval [CI], 8.8-10.2) vs patients with CNS metastases (3.63 months; 95% CI, 3.4-3.9). Among patients with CNS metastases, median OS for targeted therapy, immunotherapy, and chemotherapy was 6 (95% CI, 2.5-9.6), 5.5 (95% CI, 3.8-7.5), and 4.5 (95% CI, 3.8-5.4) months, respectively, vs 2.4 (95% CI, 2.1-2.7) and 2.1 (95% CI, 1.8-2.7) months for local radiotherapy and no treatment, respectively. Stereotactic radiosurgery demonstrated higher OS vs whole-brain radiation therapy (median, 4.98 [95% CI, 3.5-7.5] vs 2.4 [95% CI, 2.1-2.7] months).

CONCLUSION

Patients with CNS metastases from melanoma remain a population with high unmet medical need despite recent advances in treatment. Systemic treatments (eg, BRAF-targeted therapy and immunotherapy) and stereotactic radiosurgery demonstrated meaningful but modest improvements in OS. Further explorations of combinations of radiotherapy, BRAF-targeted therapies, and immunotherapies are needed.

Current State of Target Treatment in BRAF Mutated Melanoma

Incidence of melanoma has been constantly growing during the last decades. Although most of the new diagnoses are represented by thin melanomas, the number of melanoma-related deaths in 2018 was 60,712 worldwide (Global Cancer Observatory, 2019). Until 2011, no systemic therapy showed to improve survival in patients with advanced or metastatic melanoma. At that time, standard of care was chemotherapy, with very limited results. The identification of BRAF V600 mutation, and the subsequent introduction of BRAF targeting drugs, radically changed the clinical practice and dramatically improved outcomes. In this review, we will retrace the development of molecular-target drugs and the current therapeutic scenario for patients with BRAF mutated melanoma, from the introduction of BRAF inhibitors as single agents to modern clinical practice. We will also discuss the resistance mechanisms identified so far, and the future therapeutic perspectives in BRAF mutated melanoma.

Management of Immunotherapy Adverse Events in Oncological Patients: Anti-CTLA-4, Anti-PD-1/PD-L1

BACKGROUND

The widespread use of immunotherapy drugs in the oncological field has led to the spread of new toxicities compared to the more common chemotherapy treatments. This is because immunotherapy with anti-CTLA-4 (Cytotoxic T Lymphocytes-Associated Antigen 4), anti- PD-1 and anti-PD-L1 monoclonal antibodies has become the standard-of-care in a growing number of indications. Any organ or tissue can be involved, but more commonly, side effects are reported regarding skin, colon, endocrine glands, liver, lung and kidney. Other less frequent, but more serious, adverse events are neurological and myocarditis.

METHODS

We performed an electronic search on PUBMED of the literature concerning immunotherapy- related toxicities and their management in oncological patients from 2007 to 2020, with particular attention to the most recent publications.

AIM

To summarize the different types of immunotherapy-related toxicities, together with their incidence and diagnosis, and to simplify their management, especially in the emergency setting.

CONCLUSION

Usually, for grade I toxicities, it is not recommended to stop immunotherapy; for most of grade II toxicities, immunotherapy should be postponed to when toxicity will have regressed to grade I, considering the possibility of corticosteroid treatment for most toxicities. The majority of grade III and IV require administration of high-dose corticosteroid intravenous therapy and suspension of immunotherapy. Mortality related to immune checkpoint inhibitors' toxicity, occurring at a rate of 0.3-1.3%, is well below fatality rates due to other oncologic interventions and should not discourage the promising results so far reached by immunotherapy.

Metastatic melanoma: Surgical treatment of brain metastases - Analysis of 110 patients

New Zealand has one of the highest rates of melanoma in the world. In up to 10% of cases, the disease is metastatic at diagnosis. Cerebral metastatic involvement carries a particularly poor prognosis. 110 patients were included in the analysis. A retrospective consecutive series of patients treated surgically at Auckland City Hospital were studied, with parameters of demographics, tumour characteristics, surgery, pathology, systemic therapy and survival analysed. Mean age was 59.9 years (range 22-81 years). Median survival from date of surgery was 8.1 months (95% CI 6.9-9.4 months). Of the 58 patients tested for BRAF mutation, 28 were positive, similar to previously published data. This conferred a better prognosis with median overall survival of 12.3 months (95% CI 7.2-17.3 months) compared to 7.8 months (95% CI 5.6-10 months) for those who were negative (p < 0.05). Survival correlated positively with extent of surgical resection. Both BRAF positive status and targeted and/or immunotherapy were significant predictors of improved survival. In this cohort, radiation therapy did not show a statistically significant improvement in overall survival. Survival from resection of cerebral metastases from melanoma is improving. Survival benefit is conferred by BRAF mutation, solitary metastasis and gross total resection of lesion.

Metastases to the central nervous system: Molecular basis and clinical considerations

BACKGROUND

Metastatic tumors are the most common malignancies of the central nervous system (CNS) in adults. CNS metastases are associated with unfavorable prognosis, high morbidity and mortality. Lung cancer is the most common source of brain metastases, followed by breast cancer and melanoma. Rising incidence is primarily due to improvements in systemic control of primary malignancies, prolonged survival and advances in cancer detection.

PURPOSE

To provide an overview of the metastatic cascade and the role of angiogenesis, neuroinflammation, metabolic adaptations, and clinical details about brain metastases from different primary tumors.

METHODS

A review of the literature on brain metastases was conducted, focusing on the pathophysiology and clinical aspects of the disease. PubMed was used to search for relevant articles published from January 1975 through December 2019 using the keywords brain metabolism, brain metastasis, metastatic cascade, molecular mechanisms, incidence, risk factors, and prognosis. 146 articles met the criteria and were included in this review.

DISCUSSION

Some primary tumors have a higher tendency to metastasize to the CNS. Establishing a suitable metastatic microenvironment is important in maintaining tumor cell growth and survival. Magnetic resonance imaging (MRI) is a widely used tool for diagnosis and treatment monitoring. Available treatments include surgery, radiotherapy, stereotactic radiosurgery, chemotherapy, immunotherapy, and systemic targeted therapies.

CONCLUSIONS

Prevention of metastases to the CNS remains a difficult challenge. Advances in screening of high-risk patients and future development of novel treatments may improve patient outcomes.

Aquaporin-1 Protein Expression of the Primary Tumor May Predict Cerebral Progression of Cutaneous Melanoma

Brain metastasis is a frequent complication of the progression of malignant melanoma. In a previous study aquaporin 1 (AQP1) protein expression was found to be associated with increased mortality and decreased progression free survival in cutaneous melanoma. To explore further the potential of this marker we studied the AQP1 protein expression in 67 metastatic melanoma patients using immunohistochemistry. Primary tumor samples were acquired from patients with brain (BR) (n = 44) and extra-cranial (EC) (n = 23) metastases, while brain metastatic samples were collected during neurosurgical resection (n = 5). Patients with brain metastases had shorter overall survival (p = 0.02) and significantly higher AQP1 expression in the primary tumors (median H-score = 250 vs. 140, p = 0.044) as compared to patients of the EC metastasis group. AQP1 expression was found to be significantly lower in the brain metastases compared to the corresponding primary tumors (median H-score = 35 vs. 300 p = 0.01). However, in brain metastases AQP1 expression was heterogenous, AQP1 protein was more abundant in the melanoma cells far away from the capillaries as compared to tumor cells adjacent to vessels indicating a hypoxia-driven expression of AQP1. We suggest that AQP1 expression could well be a prognostic marker of brain metastatic potential of human cutaneous melanoma.

CRISPR-Cas9 Knockdown and Induced Expression of CD133 Reveal Essential Roles in Melanoma Invasion and Metastasis

CD133, known as prominin1, is a penta-span transmembrane glycoprotein presumably a cancer stem cell marker for carcinomas, glioblastomas, and melanomas. We showed that CD133(+) ‘melanoma-initiating cells’ are associated with chemoresistance, contributing to poor patient outcome. The current study investigates the role(s) of CD133 in invasion and metastasis. Magnetic-activated cell sorting of a melanoma cell line (BAKP) followed by transwell invasion assays revealed that CD133(+) cells are significantly more invasive than CD133(−) cells. Conditional reprogramming of BAKP CD133(+) cells maintained stable CD133 overexpression (BAK-R), and induced cancer stem cell markers, melanosphere formation, and chemoresistance to kinase inhibitors. BAK-R cells showed upregulated CD133 expression, and consequently were more invasive and metastatic than BAK-P cells in transwell and zebrafish assays. CD133 knockdown by siRNA or CRISPR-Cas9 (BAK-R-T3) in BAK-R cells reduced invasion and levels of matrix metalloproteinases MMP2/MMP9. BAK-R-SC cells, but not BAK-R-T3, were metastatic in zebrafish. While CD133 knockdown by siRNA or CRISPR-Cas9 in BAK-P cells attenuated invasion and diminished MMP2/MMP9 levels, doxycycline-induced CD133 expression in BAK-P cells enhanced invasion and MMP2/MMP9 concentrations. CD133 may therefore play an essential role in invasion and metastasis via upregulation of MMP2/MMP9, leading to tumor progression, and represents an attractive target for intervention in melanoma.

Microenvironmental Heterogeneity in Brain Malignancies

Brain tumors are among the deadliest malignancies. The brain tumor microenvironment (TME) hosts a unique collection of cells, soluble factors, and extracellular matrix components that regulate disease evolution of both primary and metastatic brain malignancies. It is established that macrophages and other myeloid cells are abundant in the brain TME and strongly correlate with aggressive phenotypes and distinct genetic signatures, while lymphoid cells are less frequent but are now known to have a pronounced effect on disease progression. Different types of brain tumors vary widely in their microenvironmental contexture, and the proportion of various stromal components impacts tumor biology. Indeed, emerging evidence suggests an intimate link between the molecular signature of tumor cells and the composition of the TME, shedding light on the mechanisms which underlie microenvironmental heterogeneity in brain cancer. In this review, we discuss the association between TME composition and the diverse molecular profiles of primary gliomas and brain metastases. We also discuss the implications of these associations on the efficacy of immunotherapy in brain malignancies. An appreciation for the causes and functional consequences of microenvironmental heterogeneity in brain cancer will be of crucial importance to the rational design of microenvironment-targeted therapies for these deadly diseases.

Inhibition of mitochondrial respiration prevents BRAF-mutant melanoma brain metastasis

Melanoma patients carry a high risk of developing brain metastases, and improvements in survival are still measured in weeks or months. Durable disease control within the brain is impeded by poor drug penetration across the blood-brain barrier, as well as intrinsic and acquired drug resistance. Augmented mitochondrial respiration is a key resistance mechanism in BRAF-mutant melanomas but, as we show in this study, this dependence on mitochondrial respiration may also be exploited therapeutically. We first used high-throughput pharmacogenomic profiling to identify potentially repurposable compounds against BRAF-mutant melanoma brain metastases. One of the compounds identified was β-sitosterol, a well-tolerated and brain-penetrable phytosterol. Here we show that β-sitosterol attenuates melanoma cell growth in vitro and also inhibits brain metastasis formation in vivo. Functional analyses indicated that the therapeutic potential of β-sitosterol was linked to mitochondrial interference. Mechanistically, β-sitosterol effectively reduced mitochondrial respiratory capacity, mediated by an inhibition of mitochondrial complex I. The net result of this action was increased oxidative stress that led to apoptosis. This effect was only seen in tumor cells, and not in normal cells. Large-scale analyses of human melanoma brain metastases indicated a significant role of mitochondrial complex I compared to brain metastases from other cancers. Finally, we observed completely abrogated BRAF inhibitor resistance when vemurafenib was combined with either β-sitosterol or a functional knockdown of mitochondrial complex I. In conclusion, based on its favorable tolerability, excellent brain bioavailability, and capacity to inhibit mitochondrial respiration, β-sitosterol represents a promising adjuvant to BRAF inhibitor therapy in patients with, or at risk for, melanoma brain metastases.

Brain Distribution and Active Efflux of Three panRAF Inhibitors: Considerations in the Treatment of Melanoma Brain Metastases

Targeted inhibition of RAF and MEK by molecularly targeted agents has been employed as a strategy to block aberrant mitogen-activated protein kinase (MAPK) signaling in melanoma. While the use of BRAF and MEK inhibitors, either as a single agent or in combination, improved efficacy in BRAF-mutant melanoma, initial responses are often followed by relapse due to acquired resistance. Moreover, some BRAF inhibitors are associated with paradoxical activation of the MAPK pathway, causing the development of secondary malignancies. The use of panRAF inhibitors, i.e., those that target all isoforms of RAF, may overcome paradoxical activation and resistance. The purpose of this study was to perform a quantitative assessment and evaluation of the influence of efflux mechanisms at the blood-brain barrier (BBB), in particular, Abcb1/P-glycoprotein (P-gp) and Abcg2/breast cancer resistance protein (Bcrp), on the brain distribution of three panRAF inhibitors: CCT196969 [1-(3-(tert-butyl)-1-phenyl-1H-pyrazol-5-yl)-3-(2-fluoro-4-((3-oxo-3,4-dihydropyrido[2,3-b]pyrazin-8-yl)oxy)phenyl)urea], LY3009120 1-(3,3-Dimethylbutyl)-3-(2-fluoro-4-methyl-5-(7-methyl-2-(methylamino)pyrido(2,3-d)pyrimidin-6-yl)phenyl)urea, and MLN2480 [4-pyrimidinecarboxamide, 6-amino-5-chloro-N-[(1R)-1-[5-[[[5-chloro-4-(trifluoromethyl)-2-pyridinyl]amino]carbonyl]-2-thiazolyl]ethyl]-]. In vitro studies using transfected Madin-Darby canine kidney II cells indicate that only LY3009120 and MLN2480 are substrates of Bcrp, and none of the three inhibitors are substrates of P-gp. The three panRAF inhibitors show high nonspecific binding in brain and plasma. In vivo studies in mice show that the brain distribution of CCT196969, LY3009120, and MLN2480 is limited, and is enhanced in transgenic mice lacking P-gp and Bcrp. While MLN2480 has a higher brain distribution, LY3009120 exhibits superior in vitro efficacy in patient-derived melanoma cell lines. The delivery of a drug to the site of action residing behind a functionally intact BBB, along with drug potency against the target, collectively play a critical role in determining in vivo efficacy outcomes.

Healthcare resource utilization in patients with metastatic melanoma receiving first-line therapy with dabrafenib + trametinib versus nivolumab or pembrolizumab monotherapy

OBJECTIVE

To compare healthcare resource utilization (HRU) between patients with metastatic melanoma (MM) initiated on first-line (1L) combination therapy with the BRAF inhibitor dabrafenib and the MEK inhibitor trametinib (D + T; oral) and those initiated on 1 L monotherapy with the anti-PD1 monoclonal antibodies nivolumab or pembrolizumab (N/P; intravenous).

METHODS

Patients with melanoma initiated on D + T or N/P from Q1/2014 to Q2/2016 (defined as 1 L treatment for MM) were identified in the Truven MarketScan database. Entropy balancing was used to reweight the N/P cohort in order to make it comparable to the D + T cohort with respect to the mean and variance of baseline covariates. HRU outcomes during 1 L therapy, reported per patient-year (PPY), were described and compared between the two cohorts post-weighting (i.e. independently of baseline covariates).

RESULTS

Of the 445 patients included, 202 and 243 were initiated on D + T and N/P, respectively. After weighting, patients initiated on N/P had more outpatient visits for drug administration during 1 L therapy than those initiated on D + T (difference = 18.6 visits PPY [95% CI = 16.0-21.1]). Patients initiated on N/P also had more outpatient office visits for reasons other than drug administration (difference = 8.1 visits PPY [95% CI = 1.9-13.7]). No significant differences were observed for other HRU parameters (i.e. inpatient admissions, inpatient days, and emergency department visits during 1 L therapy).

CONCLUSIONS

HRU during 1 L therapy was generally similar between patients initiated on D + T and N/P. Nonetheless, patients initiated on N/P had more outpatient visits, including more outpatient visits for reasons unrelated to drug administration.

Profiles of brain metastases: Prioritization of therapeutic targets

We sought to compare the tumor profiles of brain metastases from common cancers with those of primary tumors and extracranial metastases in order to identify potential targets and prioritize rational treatment strategies. Tumor samples were collected from both the primary and metastatic sites of nonsmall cell lung cancer, breast cancer and melanoma from patients in locations worldwide, and these were submitted to Caris Life Sciences for tumor multiplatform analysis, including gene sequencing (Sanger and next-generation sequencing with a targeted 47-gene panel), protein expression (assayed by immunohistochemistry) and gene amplification (assayed by in situ hybridization). The data analysis considered differential protein expression, gene amplification and mutations among brain metastases, extracranial metastases and primary tumors. The analyzed population included: 16,999 unmatched primary tumor and/or metastasis samples: 8,178 nonsmall cell lung cancers (5,098 primaries; 2,787 systemic metastases; 293 brain metastases), 7,064 breast cancers (3,496 primaries; 3,469 systemic metastases; 99 brain metastases) and 1,757 melanomas (660 primaries; 996 systemic metastases; 101 brain metastases). TOP2A expression was increased in brain metastases from all 3 cancers, and brain metastases overexpressed multiple proteins clustering around functions critical to DNA synthesis and repair and implicated in chemotherapy resistance, including RRM1, TS, ERCC1 and TOPO1. cMET was overexpressed in melanoma brain metastases relative to primary skin specimens. Brain metastasis patients may particularly benefit from therapeutic targeting of enzymes associated with DNA synthesis, replication and/or repair.

Combination PD-1 blockade and irradiation of brain metastasis induces an effective abscopal effect in melanoma

Nearly half of melanoma patients develop brain metastases during the course of their disease. Despite advances in both localized radiation and systemic immunotherapy, brain metastases remain difficult to treat, with most patients surviving less than 5 months from the time of diagnosis. While both treatment regimens have individually shown considerable promise in treating metastatic melanoma, there is interest in combining these strategies to take advantage of potential synergy. In order to study the ability of local radiation and anti-PD-1 immunotherapy to induce beneficial anti-tumor immune responses against distant, unirradiated tumors, we used two mouse models of metastatic melanoma in the brain, representing BRAF mutant and non-mutant tumors. Combination treatments produced a stronger systemic anti-tumor immune response than either treatment alone. This resulted in reduced tumor growth and larger numbers of activated, cytotoxic CD8⁺ T cells, even in the unirradiated tumor, indicative of an abscopal effect. The immune-mediated effects were present regardless of BRAF status. These data suggest that irradiation of brain metastases and anti-PD-1 immunotherapy together can induce abscopal anti-tumor responses that control both local and distant disease.

MMP-9 as a Candidate Marker of Response to BRAF Inhibitors in Melanoma Patients With BRAFV600E Mutation Detected in Circulating-Free DNA

The BRAF^V600E mutation is associated with melanoma development and its detection in circulating-free DNA cannot be observed in all melanoma patients harboring this mutation in tumor specimens. Beside the circulating-free DNA BRAF^V600E mutation, other markers of therapeutic response should be identified. Matrix metalloproteinase-9 (MMP-9) could be one of them as its role as indicator of invasiveness in melanoma have been explored. In this study, MMP-9 was evaluated in melanoma cells after treatment with dabrafenib. In vitro data were validated in 26 melanoma patients, of which 14 treated with BRAF inhibitor alone and 12 treated with both BRAF and MEK inhibitors, by ELISA assay and droplet digital PCR for measuring MMP-9 serum levels and circulating-free DNA BRAF^V600E mutation, respectively. Statistical analyses were performed to evaluate the prognostic significance of MMP-9, progression-free survival (PFS) and overall survival (OS) according to the BRAF^V600E mutation and MMP-9 levels. The performed analyses showed that MMP-9 and pEKR1-2 were statistically down-regulated in melanoma cells after treatment with dabrafenib. Circulating-free DNA BRAF^V600E mutation was detected in 11 out of 26 melanoma patients showing higher levels of MMP-9 compared to those with undetectable BRAF^V600E mutation. Furthermore, higher levels of MMP-9 and circulating-free DNA BRAF^V600E mutation were associated with lower PFS and OS. Finally, the monitoring of therapy showed that MMP-9 significantly decreased at T1 and T2, but not at T-last, for the patients with detectable circulating-free DNA BRAF^V600E mutation. In conclusion, high levels of MMP-9 and circulating-free DNA BRAF^V600E mutation are associated with poor PFS and OS. MMP-9 may represent a promising indicator of response to BRAF inhibitors in combination with the detection of BRAF^V600E mutation.

Leptomeningeal metastasis

Leptomeningeal metastasis (LM) results from dissemination of cancer cells to both the leptomeninges (pia and arachnoid) and cerebrospinal fluid (CSF) compartment. Breast cancer, lung cancer, and melanoma are the most common solid tumors that cause LM. Recent approval of more active anticancer therapies has resulted in improvement in survival that is partly responsible for an increased incidence of LM. Neurologic deficits, once manifest, are mostly irreversible, and often have a significant impact on patient quality of life. LM-directed therapy is based on symptom palliation, circumscribed use of neurosurgery, limited field radiotherapy, intra-CSF and systemic therapies. Novel methods of detecting LM include detection of CSF circulating tumor cells and tumor cell-free DNA. A recent international guideline for a standardization of response assessment in LM may improve cross-trial comparisons as well as within-trial evaluation of treatment. An increasing number of retrospective studies suggest that molecular-targeted therapy, such as EGFR and ALK inhibitors in lung cancer, trastuzumab in HER2+ breast cancer, and BRAF inhibitors in melanoma, may be effective as part of the multidisciplinary management of LM. Prospective randomized trials with standardized response assessment are needed to further validate these preliminary findings.

Patterns of disease control and survival in patients with melanoma brain metastases undergoing immune-checkpoint blockade

OBJECTIVES

Immune-checkpoint blockers (ICBs) significantly prolong overall survival (OS) in patients with advanced melanoma. Limited data are available on the efficacy and clinical benefit in patients with melanoma brain metastases (MBMs). The aim of this study was to determine whether ICB is active in an unselected cohort treated of patients with known brain metastases and if disease control correlates with the survival.

METHODS

A total of 385 patients with metastatic malignant melanoma treated with ICB as monotherapy between 2005 and 2017 in two tertiary referral centres were included. Patient records were searched for the development of brain metastases. Demographic and clinical data of all patients were collected retrospectively.

RESULTS

We identified 177 patients with MBM who received ICBs (ipilimumab, nivolumab, pembrolizumab). Patients with and without brain metastases received similar ICB regimens. Prognosis was inferior in patients with brain metastases; patients with >1 brain metastasis showed even poorer survival. For extracranial (ec) metastases, disease control was associated with improved survival. However, when comparing patients with intracranial (ic) disease control during immunotherapy to patients with ic disease progression, no difference in OS could be observed.

CONCLUSIONS

In our study, ec disease control was the dominant predictive factor for OS in both patients with or without melanoma brain metastases. These data indicate that clinical trials in melanoma patients with brain metastases should address end-points such as symptom control, quality of life or OS in addition to ic response rates.

Unmasking of intracranial metastatic melanoma during ipilimumab/nivolumab therapy: case report and literature review

BACKGROUND

While data from several studies over the last decade has demonstrated that introduction of immunologic checkpoint blockage therapy with anti-CTLA-4/PD-1 drugs leads to improved survival in metastatic melanoma patients, relatively little is known about brain-specific therapeutic response and adverse events in the context of immunotherapeutic treatment of intracranial disease. Here we report two independent cases of new intracranial metastases presenting after initiation of combined checkpoint blockade Ipilimumab and Nivolumab for recurrent metastatic melanoma in the context of positive systemic disease response.

CASE PRESENTATION

Case #1: A 43-year-old Caucasian male with Stage III melanoma of the left knee had subsequent nodal, hepatic and osseous metastases and was started on ipilimumab/nivolumab. He developed an intractable headache one week later. MRI revealed new enhancing and hemorrhagic brain metastases. After 6 weeks of immunotherapy, there was interval hemorrhage of a dominant intracranial lesion but substantial improvement in systemic metastatic disease. Durable, near complete intracranial and systemic response was achieved after completion of both induction and maintenance immunotherapy. Case #2: A 58-year old Caucasian woman with stage II melanoma of the right index finger developed cutaneous, pulmonary and hepatic metastases within 4 months of adjuvant radiation. Although combined checkpoint blockade resulted in improvement in both cutaneous and systemic disease, brain MR performed for eye discomfort demonstrated new enhancing and hemorrhagic brain metastases. Serial MR imaging five months later revealed only a solitary focus of brain enhancement with continued improved systemic disease.

CONCLUSIONS

These cases raise the question of whether the initial immune activation and modulation of the blood brain barrier by Ipilimumab/Nivolumab somehow "unmasks" previously clinically silent metastatic disease, rather than representing new or progressive metastatic disease. An overview of currently available literature discussing the role of immune checkpoint blockade in the treatment of intracranial metastatic melanoma will be provided, as well as discussion highlighting the need for future work elucidating the response of brain metastases to anti-CTLA/PD-1 drugs and documentation of brain-specific adverse events.

Survival and clinical outcomes of patients with melanoma brain metastasis in the era of checkpoint inhibitors and targeted therapies

Background

Melanoma brain metastasis is associated with an extremely poor prognosis, with a median overall survival of 4–5 months. Since 2011, the overall survival of patients with stage IV melanoma has been significantly improved with the advent of new targeted therapies and checkpoint inhibitors. We analyze the survival outcomes of patients diagnosed with brain metastasis after the introduction of these novel drugs.

Methods

We performed a retrospective analysis of our melanoma center database and identified 79 patients with brain metastasis between 2011 and 2015.

Results

The median time from primary melanoma diagnosis to brain metastasis was 3.2 years. The median overall survival duration from the time of initial brain metastasis was 12.8 months. Following a diagnosis of brain metastasis, 39 (49.4%), 28 (35.4%), and 24 (30.4%) patients were treated with anti-CTLA-4 antibody, anti-PD-1 antibody, or BRAF inhibitors (with or without a MEK inhibitor), with a median overall survival of 19.2 months, 37.9 months and 12.7 months, respectively. Factors associated with significantly reduced overall survival included male sex, cerebellar metastasis, higher number of brain lesions, and treatment with whole-brain radiation therapy. Factors associated with significantly longer overall survival included treatment with craniotomy, stereotactic radiosurgery, or with anti-PD-1 antibody after initial diagnosis of brain metastasis.

Conclusions

These results show a significant improvement in the overall survival of patients with melanoma brain metastasis in the era of novel therapies. In addition, they suggest the activity of anti-PD-1 therapy specifically in the setting of brain metastasis.

Sensitivity of different MRI sequences in the early detection of melanoma brain metastases

BACKGROUND

After the emergence of new MRI techniques such as susceptibility- and diffusion-weighted imaging (SWI and DWI) and because of specific imaging characteristics of melanoma brain metastases (MBM), it is unclear which MRI sequences are most beneficial for detection of MBM. This study was performed to investigate the sensitivity of six clinical MRI sequences in the early detection of MBM.

METHODS

Medical records of all melanoma patients referred to our center between November 2005 and December 2016 were reviewed for presence of MBM. Analysis encompassed six MRI sequences at the time of initial diagnosis of first or new MBM, including non-enhanced T1-weighted (T1w), contrast-enhanced T1w (ceT1w), T2-weighted (T2w), T2w-FLAIR, susceptibility-weighted (SWI) and diffusion-weighted (DWI) MRI. Each lesion was rated with respect to its conspicuity (score from 0-not detectable to 3-clearly visible).

RESULTS

Of 1210 patients, 217 with MBM were included in the analysis and up to 5 lesions per patient were evaluated. A total of 720 metastases were assessed and all six sequences were available for 425 MBM. Sensitivity (conspicuity ≥2) was 99.7% for ceT1w, 77.0% for FLAIR, 64.7% for SWI, 61.0% for T2w, 56.7% for T1w, and 48.4% for DWI. Thirty-one (7.3%) of 425 lesions were only detectable by ceT1w but no other sequence.

CONCLUSIONS

Contrast-enhanced T1-weighting is more sensitive than all other sequences for detection of MBM. Disruption of the blood-brain-barrier is consistently an earlier sign in MBM than perifocal edema, signal loss on SWI or diffusion restriction.

Immunotherapy and targeted therapy in brain metastases: emerging options in precision medicine

Brain metastases (BM) continue to represent an unmet clinical need in oncology. Immunotherapy and targeted therapy hold great promise in the treatment of BM. Emerging data are confirming the activity of these agents in patients with BM. Genomic studies have confirmed that clinically actionable mutations are present in BM and they can be used in clinical studies to link targeted therapies with their genetic targets. Furthermore, as molecular signatures associated with sensitivity and resistance to immunotherapies are developed, we will better be able to select BM patients who will most benefit from these therapies. Understanding the genetic and immune evolution within BM should drive the next generation of immunotherapy and target therapy, as well as increase the accuracy of the selection process for these therapies.

Does the distribution pattern of brain metastases during BRAF inhibitor therapy reflect phenotype switching?

Brain metastases (brain mets) are frequent in metastatic melanoma patients. The aim of this study was to investigate the morphology and progression pattern of brain mets in melanoma patients treated with BRAF inhibitors (BRAFi) compared with patients who did not receive targeted therapy (BRAFi group and control group). The number and size of brain mets were compared between a baseline and a comparative MRI at progression. The number of brain mets was grouped into seven number classes (N=1-4, N=5-10, N=11-20, N=21-30, N=31-40, N=41-50, and N>50) and its difference was reported as the change of class that occurred. The mean size of the newly developed lesions was determined by representative measurements and the evolution of three persisting target lesions was assessed on the basis of modified RECIST criteria. Of 96 patients studied, 42 were in the BRAFi group and 54 were in the control group. Patients under BRAFi treatment had a significantly greater increase in the number of brain mets, where the median change of class for the BRAFi compared with the control group was 2 versus 0 (P<0.01). The mean size of the new lesions was smaller in the BRAFi group. Pre-existing target lesions did not show any prominent or different patterns of how they evolved in either group. Brain mets in patients treated with BRAFi showed a progression pattern characterized by a high propensity to disseminate, which might reflect an in-vivo manifestation of phenotype switching in response to targeted therapy, with a predominance of the invasive/migratory tumor cell phenotype. Drivers of invasiveness may present promising targets for therapeutic interventions.

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.

The Evolving Landscape of Brain Metastasis

Metastasis, involving the spread of systemic cancer to the brain, results in neurologic disability and death. Current treatments are largely palliative in nature; improved therapeutic approaches represent an unmet clinical need. However, recent experimental and clinical advances challenge the bleak long-term outcome of this disease. Encompassing key recent findings in epidemiology, genetics, microenvironment, leptomeningeal disease, neurocognition, targeted therapy, immunotherapy, and prophylaxis, we review preclinical and clinical studies to provide a comprehensive picture of contemporary research and the management of secondary brain tumors.