The development of brain metastases in patients with different therapeutic strategies for metastatic renal cell cancer

A diagnosis of brain metastasis (BM) significantly affects quality of life in patients with metastatic renal cell cancer (mRCC). Although systemic treatments have shown efficacy in mRCC, active surveillance (AS) is still commonly used in clinical practice. In this single-center cohort study, we assessed the impact of different initial treatment strategies for metastatic RCC (mRCC) on the development of BM. All consecutive patients diagnosed with mRCC between 2011 and 2022 were included at the Erasmus MC Cancer Institute, the Netherlands, and a subgroup of patients with BM was selected. In total, 381 patients with mRCC (ECM, BM, or both) were identified. Forty-six patients had BM of whom 39 had metachronous BM (diagnosed ≥1 month after ECM). Twenty-five (64.1%) of these 39 patients with metachronous BM had received prior systemic treatment for ECM and 14 (35.9%) patients were treatment naive at BM diagnosis. The median BM-free survival since ECM diagnosis was significantly longer (p = .02) in previously treated patients (29.0 [IQR 12.6-57.0] months) compared to treatment naive patients (6.8 [IQR 1.0-7.0] months). In conclusion, patients with mRCC who received systemic treatment for ECM prior to BM diagnosis had a longer BM-free survival as compared to treatment naïve patients. These results emphasize the need for careful evaluation of treatment strategies, and especially AS, for patients with mRCC.

Outcome of adjuvant immunotherapy in a real-world nation-wide cohort of patients with melanoma

BACKGROUND

Clinical trials have demonstrated promising outcomes for adjuvant immunotherapy in patients with resected melanoma. Real-life data provide valuable insights to support patient guidance and treatment decisions.

METHODS

Observational population-based study examining a national cohort of patients with resected stage III-IV melanoma referred for adjuvant therapy. Data were extracted from the Danish Metastatic Melanoma Database (DAMMED).

RESULTS

Between November 2018 and January 2022, 785 patients received adjuvant anti-PD-1. The majority had stage III resected melanoma (87%), normal LDH levels (80%), and performance score 0 (87%). Patients were followed for a median of 25.6 months (95%CI 24-28). The median recurrence-free survival (RFS) and melanoma-specific survival (MSS) were not reached. The RFS was 78% (95%CI 75-81), 66% (63-70), and 59% (55-63); MSS was 97% (95-98), 93% (91-95), and 87% (84-90) at 1-, 2-, and 3-year; respectively. Less than half (42%) of the patients finalized planned therapy, 32% discontinued due to toxicity, and 19% due to melanoma recurrence. Patients discontinuing adjuvant treatment prematurely, without recurrence, had similar outcomes as patients finalizing therapy. In a multivariable analysis, ipilimumab plus nivolumab did not improve outcomes compared to ipilimumab monotherapy as a first-line metastatic treatment after adjuvant anti-PD-1.

CONCLUSION

Survival outcomes in real-world patients with melanoma treated with adjuvant anti-PD-1 align with results from the randomized controlled trials. Patients discontinuing therapy prematurely, for other reasons than recurrence, had similar outcomes as patients finalizing planned treatment. First-line metastatic treatment with ipilimumab and nivolumab post-adjuvant anti-PD-1 did not show improved outcomes compared to ipilimumab/anti-PD-1 monotherapy.

Symptomatic brain metastases in melanoma

Although clinical outcomes in metastatic melanoma have improved in recent years, the morbidity and mortality of symptomatic brain metastases remain challenging. Response rates and survival outcomes of patients with symptomatic melanoma brain metastases (MBM) are significantly inferior to patients with asymptomatic disease. This review focusses upon the specific challenges associated with the management of symptomatic MBM, discussing current treatment paradigms, obstacles to improving clinical outcomes and directions for future research.

Long-Term Intracranial Outcomes With Combination Dual Immune-Checkpoint Blockade and Stereotactic Radiosurgery in Patients With Melanoma and Non-Small Cell Lung Cancer Brain Metastases

PURPOSE

The intracranial benefit of offering dual immune-checkpoint inhibition (D-ICPI) with ipilimumab and nivolumab to patients with melanoma or non-small cell lung cancer (NSCLC) receiving stereotactic radiosurgery (SRS) for brain metastases (BMs) is unknown. We hypothesized that D-ICPI improves local control compared with SRS alone.

METHODS AND MATERIALS

Patients with melanoma or NSCLC treated with SRS from 2014 to 2022 were evaluated. Patients were stratified by treatment with D-ICPI, single ICPI (S-ICPI), or SRS alone. Local recurrence, intracranial progression (IP), and overall survival were estimated using competing risk and Kaplan-Meier analyses. IP included both local and distant intracranial recurrence.

RESULTS

Two hundred eighty-eight patients (44% melanoma, 56% NSCLC) with 1,704 BMs were included. Fifty-three percent of patients had symptomatic BMs. The median follow-up was 58.8 months. Twelve-month local control rates with D-ICPI, S-ICPI, and SRS alone were 94.73% (95% CI, 91.11%-96.90%), 91.74% (95% CI, 89.30%-93.64%), and 88.26% (95% CI, 84.07%-91.41%). On Kaplan-Meier analysis, only D-ICPI was significantly associated with reduced local recurrence (P = .0032). On multivariate Cox regression, D-ICPI (hazard ratio [HR], 0.4003; 95% CI, 0.1781-0.8728; P = .0239) and planning target volume (HR, 1.022; 95% CI, 1.004-1.035; P = .0059) correlated with local control. One hundred seventy-three (60%) patients developed IP. The 12-month cumulative incidence of IP was 41.27% (95% CI, 30.27%-51.92%), 51.86% (95% CI, 42.78%-60.19%), and 57.15% (95% CI, 44.98%-67.59%) after D-ICPI, S-ICPI, and SRS alone. On competing risk analysis, only D-ICPI was significantly associated with reduced IP (P = .0408). On multivariate Cox regression, D-ICPI (HR, 0.595; 95% CI, 0.373-0.951; P = .0300) and presentation with >10 BMs (HR, 2.492; 95% CI, 1.668-3.725; P < .0001) remained significantly correlated with IP. The median overall survival after D-ICPI, S-ICPI, and SRS alone was 26.1 (95% CI, 15.5-40.7), 21.5 (16.5-29.6), and 17.5 (11.3-23.8) months. S-ICPI, fractionation, and histology were not associated with clinical outcomes. There was no difference in hospitalizations or neurologic adverse events between cohorts.

CONCLUSIONS

The addition of D-ICPI for patients with melanoma and NSCLC undergoing SRS is associated with improved local and intracranial control. This appears to be an effective strategy, including for patients with symptomatic or multiple BMs.

Immunotherapy in patients with brain metastasis: advances and challenges for the treatment and the application of circulating biomarkers

The central nervous system (CNS) is one of the most frequent metastatic sites of various cancers, including lung cancer, breast cancer and melanoma. The development of brain metastases requires a specific therapeutic approach and is associated with high mortality and morbidity in cancer patients. Advances in precision medicine and the introduction in recent years of new drugs, such as immunotherapy, have made it possible to improve the prognosis of these patients by improving survival and quality of life. New diagnostic techniques such as liquid biopsy allow real-time monitoring of tumor evolution, providing molecular information on prognostic and predictive biomarkers of response to treatment in blood or other fluids. In this review, we perform an exhaustive update of the clinical trials that demonstrate the utility of immunotherapy in patients with brain metastases and the potential of circulating biomarkers to improving the results of efficacy and toxicity in this subgroup of patients.

Novel Mechanisms and Future Opportunities for the Management of Radiation Necrosis in Patients Treated for Brain Metastases in the Era of Immunotherapy

Radiation necrosis, also known as treatment-induced necrosis, has emerged as an important adverse effect following stereotactic radiotherapy (SRS) for brain metastases. The improved survival of patients with brain metastases and increased use of combined systemic therapy and SRS have contributed to a growing incidence of necrosis. The cyclic GMP-AMP (cGAMP) synthase (cGAS) and stimulator of interferon genes (STING) pathway (cGAS-STING) represents a key biological mechanism linking radiation-induced DNA damage to pro-inflammatory effects and innate immunity. By recognizing cytosolic double-stranded DNA, cGAS induces a signaling cascade that results in the upregulation of type 1 interferons and dendritic cell activation. This pathway could play a key role in the pathogenesis of necrosis and provides attractive targets for therapeutic development. Immunotherapy and other novel systemic agents may potentiate activation of cGAS-STING signaling following radiotherapy and increase necrosis risk. Advancements in dosimetric strategies, novel imaging modalities, artificial intelligence, and circulating biomarkers could improve the management of necrosis. This review provides new insights into the pathophysiology of necrosis and synthesizes our current understanding regarding the diagnosis, risk factors, and management options of necrosis while highlighting novel avenues for discovery.

Impact of Novel Treatments in Patients with Melanoma Brain Metastasis: Real-World Data

BACKGROUND

Melanoma brain metastasis (MBM) is associated with poor outcome, but targeted therapies (TTs) and immune checkpoint inhibitors (ICIs) have revolutionized treatment over the past decade. We assessed the impact of these treatments in a real-world setting.

METHODS

A single-center cohort study was performed at a large, tertiary referral center for melanoma (Erasmus MC, Rotterdam, the Netherlands). Overall survival (OS) was assessed before and after 2015, after which TTs and ICIs were increasingly prescribed.

RESULTS

There were 430 patients with MBM included; 152 pre-2015 and 278 post-2015. Median OS improved from 4.4 to 6.9 months (HR 0.67, p < 0.001) after 2015. TTs and ICIs prior to MBM diagnosis were associated with poorer median OS as compared to no prior systemic treatment (TTs: 2.0 vs. 10.9 and ICIs: 4.2 vs. 7.9 months, p < 0.001). ICIs directly after MBM diagnosis were associated with improved median OS as compared to no direct ICIs (21.5 vs. 4.2 months, p < 0.001). Stereotactic radiotherapy (SRT; HR 0.49, p = 0.013) and ICIs (HR 0.32, p < 0.001) were independently associated with improved OS.

CONCLUSION

After 2015, OS significantly improved for patients with MBM, especially with SRT and ICIs. Demonstrating a large survival benefit, ICIs should be considered first after MBM diagnosis, if clinically feasible.

Real-world outcomes with ipilimumab and nivolumab in advanced melanoma: a multicentre retrospective study

PURPOSE

To assess efficacy and toxicity of combination immunotherapy with ipilimumab plus nivolumab in routine practice in a retrospective multicentre cohort of patients with advanced melanoma.

PATIENTS AND METHODS

This retrospective analysis included patients with advanced melanoma treated with ipilimumab and nivolumab between October 2015 and January 2020 at six centres in Australia, Europe and the United States of America. We describe efficacy outcomes (overall survival [OS], progression-free survival [PFS] and objective response rate [ORR]) in treatment-naïve and pre-treated patients, with and without brain metastases, plus treatment-related adverse events (trAEs) in all patients treated.

RESULTS

A total of 697 patients were identified; 472 were treatment-naïve of which 138 (29.2%) had brain metastases, and 225 were previously treated of which 102 (45.3%) had brain metastases. At baseline, 32.3% had stage M1c and 34.4% stage M1d disease. Lactate dehydrogenase was high in 280 patients (40.2%). With a median follow-up of 25.9 months, median OS in the 334 treatment-naïve patients without brain metastases was 53.7 months (95% confidence interval [CI] 40.8-NR) and 38.7 months (95% CI 18.6-NR) for the 138 treatment-naïve patients with brain metastases. For the entire cohort the ORR was 48%, for treatment-naïve patients without brain metastases ORR was 56.6% with a median PFS of was 13.7 months (95% CI 9.6-26.5). Median PFS was 7.9 months (95% CI 5.8-10.4) and OS 38 months (95% CI 31-NR) for the entire cohort. Grade 3-4 trAE were reported in 44% of patients, and 4 (0.7%) treatment-related deaths (1 pneumonitis, 2 myocarditis and 1 colitis) were recorded.

CONCLUSION

The outcome and toxicity of combination immunotherapy with ipilimumab and nivolumab in a real-world patient population are similar to those reported in pivotal trials.

Local control of brain metastases with osimertinib alone in patients with EGFR-mutant non-small cell lung cancer

PURPOSE

Although osimertinib has excellent intracranial activity in metastatic non-small cell lung cancer (NSCLC) with exon 19 deletion or L858R EGFR alterations, measures of local control of brain metastases are less well-reported. We describe lesion-level outcomes of brain metastases treated with osimertinib alone.

METHODS

We retrospectively reviewed patients with EGFR-mutant NSCLC with untreated brain metastasis measuring ≥ 5 mm at the time of initiating osimertinib. Cumulative incidence of local recurrence in brain (LRiB) was calculated with death as a competing risk, and univariable and multivariable analyses were conducted to identify factors associated with LRiB.

RESULTS

We included 284 brain metastases from 37 patients. Median follow-up was 20.1 months. On initial MRI after starting osimertinib, patient-level response was complete response (CR) in 11 (15%), partial response (PR) in 33 (45%), stable disease (SD) in 18 (25%) and progressive disease (PD) in 11 (15%). The 1-year cumulative incidence of LRiB was 14% (95% CI 9.9-17.9) and was significantly different in patients with a CR (0%), PR (4%), and SD (11%; p = 0.02). Uncontrolled primary tumor (adjusted hazard ratio [aHR] 3.78, 95% CI 1.87-7.66; p < 0.001), increasing number of prior systemic therapies (aHR 2.12, 95% CI 1.49-3.04; p < 0.001), and higher ECOG score (aHR 7.8, 95% CI 1.99-31.81; p = 0.003) were associated with LRiB.

CONCLUSIONS

Although 1-year cumulative incidence of LRiB is < 4% with a CR or PR, 1-year cumulative incidence of LRiB is over 10% for patients with less than a PR to osimertinib on initial MRI. These patients should be followed closely for need for additional treatment such as stereotactic radiosurgery.

Maximal surgical tumour load reduction in immune-checkpoint inhibitor naïve patients with melanoma brain metastases correlates with prolonged survival

BACKGROUND

Recent therapeutic advances in metastatic melanoma have led to improved overall survival (OS) rates, with consequently an increased incidence of brain metastases (BM). The role of BM resection in the era of targeted and immunotherapy should be reassessed. In the current study we analysed the role of residual intracranial tumour load in a cohort of melanoma BM patients.

METHODS

Retrospective single-centre analysis of a prospective registry of resected melanoma BM from 2013 to 2021. Correlations of residual tumour volume and outcome were determined with respect to patient, tumour and treatment regimens characteristics.

RESULTS

121 individual patients (66% male, mean age 59.9 years) were identified and included in the study. Pre- and postoperative systemic treatments included BRAF/MEK inhibitors, as well as combination or monotherapy of immune-checkpoint inhibitors (ICIs). Median OS of the entire cohort was 20 months. Cox proportional-hazard analysis revealed postoperative anti-CTLA4+anti-PD-1 therapy (HR 0.07, p = .01) and postoperative residual intracranial tumour burden (HR 1.4, p = .027) as significant predictors for OS. Further analysis revealed that ICI-naïve patients with residual tumour volume ≤3.5 cm³ and postoperative ICI showed significantly prolonged OS compared to patients with residual volume >3.5 cm³ (p < .0001). Subgroup analysis of ICI-naïve patients showed steroid intake postoperatively to be negatively associated with OS, however residual tumour volume ≤3.5 cm³ remained independently correlated with superior OS (HR 0.14, p < .001).

CONCLUSION

Besides known predictive factors like postoperative ICI, a maximal intracranial tumour burden reduction seems to be beneficial, especially in ICI-naïve patients. This highlights the importance of local CNS control and the need to further investigating the role of initial surgical tumour load reduction in randomised clinical trials.

Combination of immunotherapy and other targeted therapies in advanced cutaneous melanoma

Cutaneous Melanoma (CM) is an aggressive cancer whose incidence is increasing worldwide. However, the knowledge of its biology and genes driving cell growth and survival allowed to develop new drugs that have improved PFS and OS of advanced disease. Both BRAF targeting agents and immune checkpoint inhibitors (ICIs) have been adopted for the treatment of metastatic disease and the adjuvant setting. Several melanoma patients show innate or acquired drug-resistance and thus new strategies are required for overcoming this complication. New ICIs have been developed, and strategies of combination or sequencing are under investigation in ongoing clinical trials. In addition, pre-clinical data have demonstrated that many strategies induce the release of neoantigens within the tumor microenvironment, thus suggesting the combination of new agents with ICIs. Here, we review the ongoing strategies in advanced CM including a dedicated section on treatment of brain metastases.

Melanoma: An immunotherapy journey from bench to bedside

Melanoma gave science a window into the role immune evasion plays in the development of malignancy. The entire spectrum of immune focused anti-cancer therapies has been subjected to clinical trials in this disease, with limited success until the immune checkpoint blockade era. That revolution launched first in melanoma, heralded a landscape change throughout cancer that continues to reverberate today.

Current Treatment Approaches and Global Consensus Guidelines for Brain Metastases in Melanoma

Background

Up to 60% of melanoma patients develop melanoma brain metastases (MBM), which traditionally have a poor diagnosis. Current treatment strategies include immunotherapies (IO), targeted therapies (TT), and stereotactic radiosurgery (SRS), but there is considerable heterogeneity across worldwide consensus guidelines.

Objective

To summarize current treatments and compare worldwide guidelines for the treatment of MBM.

Methods

Review of global consensus treatment guidelines for MBM patients.

Results

Substantial evidence supported that concurrent IO or TT plus SRS improves progression-free survival (PFS) and overall survival (OS). Guidelines are inconsistent with regards to recommendations for surgical resection of MBM, since surgical resection of symptomatic lesions alleviates neurological symptoms but does not improve OS. Whole-brain radiation therapy is not recommended by all guidelines due to negative effects on neurocognition but can be offered in rare palliative scenarios.

Conclusion

Worldwide consensus guidelines consistently recommend up-front combination IO or TT with or without SRS for the treatment of MBM.

Tumor Immune Microenvironment of Brain Metastases: Toward Unlocking Antitumor Immunity

Brain metastasis (BrM) is a devastating complication of solid tumors associated with poor outcomes. Immune-checkpoint inhibitors (ICI) have revolutionized the treatment of cancer, but determinants of response are incompletely understood. Given the rising incidence of BrM, improved understanding of immunobiologic principles unique to the central nervous system (CNS) and dissection of those that govern the activity of ICIs are paramount toward unlocking BrM-specific antitumor immunity. In this review, we seek to discuss the current clinical landscape of ICI activity in the CNS and CNS immunobiology, and we focus, in particular, on the role of glial cells in the CNS immune response to BrM.

SIGNIFICANCE

There is an urgent need to improve patient selection for and clinical activity of ICIs in patients with cancer with concomitant BrM. Increased understanding of the unique immunobiologic principles that govern response to ICIs in the CNS is critical toward identifying targets in the tumor microenvironment that may potentiate antitumor immunity.

The systemic management of central nervous system metastases and leptomeningeal disease from advanced lung, melanoma, and breast cancer with molecular drivers: An Australian perspective

The advent of systemic therapies with high intracranial efficacy in recent years is changing the therapeutic paradigm and renewing interest in the management of central nervous system (CNS) and leptomeningeal metastases from solid organ tumors. CNS metastases have traditionally heralded a dismal prognosis with median survival of 3-10 months, and were primarily treated with local therapeutic modalities, such as surgery or radiation therapy. Although these modalities still have a role in the management of CNS disease, newer agents, such as small molecule tyrosine kinase inhibitors and immune-checkpoint inhibitors, are now paving the way as an alternative therapeutic option for those with oligometastatic or low-volume intracranial disease, potentially eliminating or delaying the need for local treatment modalities in this setting. Herein, we summarize the systemic treatments with proven intracranial efficacy, currently approved for use in Australia for advanced mutation-driven non-small cell lung cancer, melanoma, and breast cancer, as well as novel agents in preclinical and clinical trial development.

Pembrolizumab for patients with leptomeningeal metastasis from solid tumors: efficacy, safety, and cerebrospinal fluid biomarkers

Background

The benefit of immune checkpoint inhibitors (ICIs) in patients with leptomeningeal metastases (LMM) is unknown.

Methods

We undertook a phase II trial of pembrolizumab in patients with LMM from solid tumors. Eligible patients had radiologic/cytologic LMM and Eastern Cooperative Oncology Group performance status 0–1. Pembrolizumab was administered intravenously at 200 mg q3W until disease progression/unacceptable toxicity. The primary endpoint was central nervous system (CNS) response after four cycles, defined radiologically/cytologically/clinically. Serial cerebrospinal fluid (CSF) was assessed for tumor-derived DNA (t-DNA) aneuploidy and cytokines.

Results

Thirteen of a planned 16 patients were treated between April 2017 and December 2019. The study closed early for poor accrual. Median age was 57 years (range: 22–79). Sixty-two percent of patients had tumors not traditionally ICI-responsive (hormone-receptor (HR)-positive breast carcinoma=39%; high-grade glioma=23%), while 38% had ICI-responsive tumors (non-small cell lung cancer (NSCLC)=23%, head and neck carcinoma=8%, cutaneous squamous carcinoma (CSC)=8%). CNS response was observed in 38% of patients at 12 weeks (95% CI 13.9% to 68.4%) by pre-defined criteria and LM-RANO, and 2 achieved durable complete responses (CSC=1, overall survival (OS) 3+ years; NSCLC=1, OS 9 months). Median CNS progression-free survival and OS was 2.9 months (95% CI 1.3 to NR) and 4.9 months (95% CI 3.7 to NR), respectively. Grade 3+ treatment-related adverse events occurred in 15% of patients. Sensitivity for LMM detection by t-DNA and cytopathology was 84.6% (95% CI 54.6% to 98.1%) and 53.9% (95% CI 25.1% to 80.8%), respectively. Pre-therapy and on-therapy CSF cytokine analysis demonstrated complete responders clustered together.

Conclusions

Pembrolizumab conferred a 38% CNS response rate in patients with LMM, a tolerable safety profile, and deep responses in selected patients with ICI-responsive tumors. CSF t-DNA may be sensitive for LMM detection, and immunologic subsets of CNS response warrant further study.

Trial registration number

NCT03091478

Primary Analysis and 4-Year Follow-Up of the Phase III NIBIT-M2 Trial in Melanoma Patients With Brain Metastases

PURPOSE

Phase II trials have shown encouraging activity with ipilimumab plus fotemustine and ipilimumab plus nivolumab in melanoma brain metastases. We report the primary analysis and 4-year follow-up of the NIBIT-M2 study, the first phase III trial comparing these regimens with fotemustine in patients with melanoma with brain metastases.

PATIENTS AND METHODS

This phase III study recruited patients 18 years of age and older with BRAF wild-type or mutant melanoma, and active, untreated, asymptomatic brain metastases from nine centers, randomized (1:1:1) to fotemustine, ipilimumab plus fotemustine, or ipilimumab plus nivolumab. The primary endpoint was overall survival (OS).

RESULTS

From January, 2013 to September, 2018, 27, 26, and 27 patients received fotemustine, ipilimumab plus fotemustine, and ipilimumab plus nivolumab. Median OS was 8.5 months [95% confidence interval (CI), 4.8-12.2] in the fotemustine arm, 8.2 months (95% CI, 2.2-14.3) in the ipilimumab plus fotemustine arm (HR vs. fotemustine, 1.09; 95% CI, 0.59-1.99; P = 0.78), and 29.2 months (95% CI, 0-65.1) in the ipilimumab plus nivolumab arm (HR vs. fotemustine, 0.44; 95% CI, 0.22-0.87; P = 0.017). Four-year survival rate was significantly higher for ipilimumab plus nivolumab than fotemustine [(41.0%; 95% CI, 20.6-61.4) vs. 10.9% (95% CI, 0-24.4; P = 0.015)], and was 10.3% (95% CI, 0-22.6) for ipilimumab plus fotemustine. In the fotemustine, ipilimumab plus fotemustine, and ipilimumab plus nivolumab arms, respectively, 11 (48%), 18 (69%), and eight (30%) patients had treatment-related grade 3 or 4 adverse events, without treatment-related deaths.

CONCLUSIONS

Compared with fotemustine, ipilimumab plus nivolumab significantly improved overall and long-term survival of patients with melanoma with asymptomatic brain metastases.

Systemic Therapy of Metastatic Melanoma: On the Road to Cure

This decade has brought significant survival improvement in patients with metastatic melanoma with targeted therapies and immunotherapies. As our understanding of the mechanisms of action of these therapeutics evolves, even more impressive therapeutic success is being achieved through various combination strategies, including combinations of different immunotherapies as well as with other modalities. This review summarizes prospectively and retrospectively generated clinical evidence on modern melanoma therapy, focusing on immunotherapy and targeted therapy with BRAF kinase inhibitors and MEK kinase inhibitors (BRAF/MEK inhibitors), including recent data presented at major conference meetings. The combination of the anti-PD-1 directed monoclonal antibody nivolumab and of the CTLA-4 antagonist ipilimumab achieves unprecedented 5-year overall survival (OS) rates above 50%; however, toxicity is high. For PD-1 monotherapy (nivolumab or pembrolizumab), toxicities are in general well manageable. Today, novel combinations of such immune checkpoint inhibitors (ICIs) are under investigation, for example with cytokines and oncolytic viruses (i.e., pegylated interleukin-2, talimogene laherparepvec). Furthermore, current studies investigate the combined or sequential use of ICIs plus BRAF/MEK inhibitors. Several studies focus particularly on poor prognosis patients, as e.g., on anti-PD-1 refractory melanoma, patients with brain metastases, or uveal melanoma. It is hoped, on the road to cure, that these new approaches further improve long term survival in patients with advanced or metastatic melanoma.

Melanoma brain metastases: Biological basis and novel therapeutic strategies

The development of brain metastases is the deadliest complication of advanced melanoma and has long been associated with a dismal prognosis. The recent years have seen incredible progress in the development of therapies for melanoma brain metastases (MBM), with both targeted therapies (the BRAF-MEK inhibitor combination) and immune checkpoint inhibitors (the anti-CTLA-4, anti-PD-1 combination) showing impressive levels of activity. Despite this, durations of response for these therapies remain lower at intracranial sites of metastasis compared to extracranial metastases and it has been suggested that there are unique features of the brain microenvironment that contribute to therapeutic escape. In this review, we outline the latest research into the biology and pathophysiology of melanoma brain metastasis development and progression. We then discuss the current status of clinical trial that are open to patients with MBM and end by describing the ongoing challenges for the field.

Perspectives in melanoma: meeting report from the "Melanoma Bridge" (December 5th-7th, 2019, Naples, Italy)

The melanoma treatment landscape changed in 2011 with the approval of the first anti-cytotoxic T-lymphocyte-associated protein (CTLA)-4 checkpoint inhibitor and of the first BRAF-targeted monoclonal antibody, both of which significantly improved overall survival (OS). Since then, improved understanding of the tumor microenvironment (TME) and tumor immune-evasion mechanisms has resulted in new approaches to targeting and harnessing the host immune response. The approval of new immune and targeted therapies has further improved outcomes for patients with advanced melanoma and other combination modalities are also being explored such as chemotherapy, radiotherapy, electrochemotherapy and surgery. In addition, different strategies of drugs administration including sequential or combination treatment are being tested. Approaches to overcome resistance and to potentiate the immune response are being developed. Increasing evidence emerges that tissue and blood-based biomarkers can predict the response to a therapy. The latest findings in melanoma research, including insights into the tumor microenvironment and new biomarkers, improved understanding of tumor immune response and resistance, novel approaches for combination strategies and the role of neoadjuvant and adjuvant therapy, were the focus of discussions at the Melanoma Bridge meeting (5-7 December, 2019, Naples, Italy), which are summarized in this report.

The Role of Anti-PD-1/PD-L1 in the Treatment of Skin Cancer

Skin cancers remain the most common group of cancers globally, and the incidence continues to rise. Although localized skin cancers tend to have excellent outcomes following surgical excisions, the less common cases that become surgically unresectable or metastatic have been associated with poor prognosis and suboptimal treatment responses to cytotoxic chemotherapy. Development of monoclonal antibodies to programmed cell death-1 receptor and its ligand (PD-1/PD-L1) have transformed the management of metastatic melanoma, squamous cell carcinoma, and Merkel cell carcinoma. These agents, as monotherapies, are associated with response rates of approximately 40-60%, many of which persist durably. Further efficacy is observed with combination immunotherapy in advanced melanoma. Early reports suggest similar activity in locally advanced or metastatic basal cell carcinoma. In this review, we describe common molecular features of skin cancers that may render them particularly susceptible to anti-PD-1/PD-L1 and detail results from key clinical trials of these agents across skin cancers. Overall, the superior response rates of skin cancer to anti-PD-1/PD-L1 compared with other solid tumor types are likely due, at least in part, to a high mutational burden and, in Merkel cell carcinoma, viral etiology. Although melanoma has been rigorously studied in the setting of anti-PD-1/PD-L1 treatment, more research is needed for the other skin cancer types to establish toxicity profiles, responses, and quality-of-life outcomes.

Anti-PD-1 and Novel Combinations in the Treatment of Melanoma-An Update

Until recently, distant metastatic melanoma was considered refractory to systemic therapy. A better understanding of the interactions between tumors and the immune system and the mechanisms of regulation of T-cells led to the development of immune checkpoint inhibitors. This review summarizes the current novel data on the treatment of metastatic melanoma with anti-programmed cell death protein 1 (PD-1) antibodies and anti-PD-1-based combination regimens, including clinical trials presented at major conference meetings. Immune checkpoint inhibitors, in particular anti-PD-1 antibodies such as pembrolizumab and nivolumab and the combination of nivolumab with the anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) antibody ipilimumab can achieve long-term survival for patients with metastatic melanoma. The anti-PD-1 antibodies nivolumab and pembrolizumab were also approved for adjuvant treatment of patients with resected metastatic melanoma. Anti-PD-1 antibodies appear to be well tolerated, and toxicity is manageable. Nivolumab combined with ipilimumab achieves a 5 year survival rate of more than 50% but at a cost of high toxicity. Ongoing clinical trials investigate novel immunotherapy combinations and strategies (e.g., Talimogene laherparepvec (T-VEC), Bempegaldesleukin (BEMPEG), incorporation or sequencing of targeted therapy, incorporation or sequencing of radiotherapy), and focus on poor prognosis groups (e.g., high tumor burden/LDH levels, anti-PD-1 refractory melanoma, and brain metastases).