Efficacy of PD-1-based immunotherapy after radiologic progression on targeted therapy in stage IV melanoma

Synthesis, physicochemical and pharmacological characterizations of a tetra-[methylimidazolium] dihydrogen decavanadate, inhibiting the IGR39 human melanoma cells development

Melanoma is a skin cancer that arises from melanocytes and can spread quickly to the other organs of the body, if not treated early. Generally, melanoma shows an inherent resistance to conventional therapies. In this regard, new potential drugs are being developed as possible treatments for melanoma. In this paper, we report the synthesis of a new decavanadate compound with organic molecules for a potential therapeutic application. The tetra-[methylimidazolium] dihydrogen decavanadate(V) salt (C4H7N2)4[H2V10O28] is characterized by single-crystal X-ray diffraction, by FT-IR, UV-Vis and 51V NMR spectroscopy, as well as by thermal analysis (TGA and DSC). The compound crystallizes in the monoclinic centrosymmetric space group P21/c. Its formula unit consists of one dihydrogen decavanadate anion [H2V10O28]4- and four organic 4-methylimidazolium cations (C4H7N2)+. Important intermolecular interactions are N-H···O and O-H···O hydrogen bonds and π-π stacking interactions between the organic cations, revealed by analysis of the Hirshfeld surface and its two-dimensional fingerprint plots. Interestingly, this compound inhibits the viability of IGR39 cells with IC50 values of 14.65 μM and 4 μM after 24 h and 72 h of treatment, respectively. The analysis of its effect by flow cytometry using an Annexin V-FITC/IP cell labeling, showed that (C4H7N2)4H2V10O28 compound induced IGR39 cell apoptosis and necrosis. Molecular docking studies performed against TNFR1 and GPR40, as putative targets, suggest that the (C4H7N2)4[H2V10O28] compound may act as inhibitor of these proteins, known to be overexpressed in melanoma cells. Therefore, we could consider it as a new potential metallodrug against melanoma.

A TCF4-dependent gene regulatory network confers resistance to immunotherapy in melanoma

To better understand intrinsic resistance to immune checkpoint blockade (ICB), we established a comprehensive view of the cellular architecture of the treatment-naive melanoma ecosystem and studied its evolution under ICB. Using single-cell, spatial multi-omics, we showed that the tumor microenvironment promotes the emergence of a complex melanoma transcriptomic landscape. Melanoma cells harboring a mesenchymal-like (MES) state, a population known to confer resistance to targeted therapy, were significantly enriched in early on-treatment biopsies from non-responders to ICB. TCF4 serves as the hub of this landscape by being a master regulator of the MES signature and a suppressor of the melanocytic and antigen presentation transcriptional programs. Targeting TCF4 genetically or pharmacologically, using a bromodomain inhibitor, increased immunogenicity and sensitivity of MES cells to ICB and targeted therapy. We thereby uncovered a TCF4-dependent regulatory network that orchestrates multiple transcriptional programs and contributes to resistance to both targeted therapy and ICB in melanoma.

Resistance to anti-PD1 therapies in patients with advanced melanoma: systematic literature review and application of the Society for Immunotherapy of Cancer Immunotherapy Resistance Taskforce anti-PD1 resistance definitions

Nearly half of advanced melanoma patients do not achieve a clinical response with anti-programmed cell death 1 protein (PD1) therapy (i.e. primary resistance) or initially achieve a clinical response but eventually progress during or following further treatment (i.e. secondary resistance). A consensus definition for tumor resistance to anti-PD1 monotherapy was published by Society for Immunotherapy of Cancer Immunotherapy Resistance Taskforce (SITC) in 2020. A systematic literature review (SLR) of clinical trials and observational studies was conducted to characterize the proportions of advanced melanoma patients who have progressed on anti-PD1 therapies. The SLR included 55 unique studies and the SITC definition of primary resistance was applied to 37 studies that specified disease progression by best overall response. Median and range of patients with primary resistance in studies that specified first-line and second-line or higher anti-PD1 monotherapy was 35.50% (21.19-39.13%; n = 4 studies) and 41.54% (30.00-56.41%, n = 3 studies); median and range of patients with primary resistance in studies that specified first-line and second-line or higher combination therapy was 30.23% (15.79-33.33%; n = 6 studies), and 70.00% (61.10-73.33%; n = 3 studies). Primary resistance to anti-PD1 monotherapies and when in combination with ipilimumab are higher in patients receiving second-line or higher therapies, in patients with acral, mucosal, and uveal melanoma, and in patients with active brain metastases. The percentage of patients with primary resistance was generally consistent across clinical trials, with variability in resistance noted for observational studies. Limitations include applying the SITC definitions to combination therapies, where consensus definitions are not yet available. Future studies should highly consider utilizing the SITC definitions to harmonize how resistance is classified and facilitate meaningful context for clinical activity.

Benefit and toxicity of programmed death-1 blockade vary by ethnicity in patients with advanced melanoma: an international multicentre observational study

BACKGROUND

Programmed cell death receptor-1 (PD-1) monotherapy is a standard treatment for advanced cutaneous melanoma, but its efficacy and toxicity are defined in white populations and remain poorly characterized in other ethnic groups, such as East Asian, Hispanic and African.

OBJECTIVES

To determine the efficacy and toxicity of PD-1 monotherapy in different ethnic groups.

METHODS

Clinical data for patients with unresectable or advanced melanoma treated with anti-PD-1 monotherapy between 2009 and 2019 were collected retrospectively from five independent institutions in the USA, Australia and China. Tumour response, survival and immune-related adverse events (irAEs) were compared by ethnicity (white vs. East Asian/Hispanic/African) across different melanoma subtypes: nonacral cutaneous (NAC)/unknown primary (UP) and acral/mucosal/uveal.

RESULTS

In total, 1135 patients were included. White patients had significantly higher objective response rate (ORR) [54%, 95% confidence interval (CI) 50-57% vs. 20%, 95% CI 13-28%; adjusted P < 0·001] and longer progression-free survival (14·2 months, 95% CI 10·7-20·3 vs. 5·4 months, 95% CI 4·5-7·0; adjusted P < 0·001) than East Asian, Hispanic and African patients in the NAC and UP subtypes. White ethnicity remained independently associated with a higher ORR (odds ratio 4·10, 95% CI 2·48-6·81; adjusted P < 0·001) and longer PFS (hazard ratio 0·58, 95% CI 0·46-0·74; adjusted P < 0·001) in multivariate analyses after adjustment for age, sex, primary anatomical location, metastasis stage, baseline lactate dehydrogenase level, mutational status and prior systemic treatment. White and East Asian/Hispanic/African patients shared similar ORR and progression-free survival in acral/mucosal/uveal melanomas. Similar melanoma-subtype-specific ethnic discrepancies were observed in complete response rate and overall survival. White patients had higher rates of gastrointestinal irAEs but lower rates of endocrine, liver and other rare types of irAEs. These differences in irAEs by ethnicity were not attributable to varying melanoma subtypes.

CONCLUSIONS

Ethnic discrepancy in clinical benefit is specific to melanoma subtype, and East Asian, Hispanic and African patients with NAC and UP melanomas have poorer clinical benefits than previously recognized. The ethnic discrepancy in toxicity observed across different melanoma subtypes warrants an ethnicity-based irAE surveillance strategy. More research is needed to elucidate the molecular and immunological determinants of these differences. What is already known about this topic? There is a great difference in response to immunotherapy between different subtypes of melanoma (cutaneous, mucosal, acral and uveal) in patients with advanced disease. What does this study add? Our data show for the first time that there are differences between different ethnic groups in terms of both response and toxicity to immunotherapy beyond the well-appreciated discrepancies due to melanoma subtype.

Efficacy and safety of anti-PD1 monotherapy or in combination with ipilimumab after BRAF/MEK inhibitors in patients with BRAF mutant metastatic melanoma

BACKGROUND

Patients with V600BRAF mutant metastatic melanoma have higher rates of progression-free survival (PFS) and overall survival (OS) with first-line anti-PD1 (PD1]+anti-CTLA-4 (IPI) versus PD1. Whether this is also true after BRAF/MEKi therapy is unknown. We aimed to determine the efficacy and safety of PD1 versus IPI +PD1 after BRAF/MEK inhibitors (BRAF/MEKi).

METHODS

Patients with V600BRAF mutant metastatic melanoma treated with BRAF/MEKi who had subsequent PD1 versus IPI+PD1 at eight centers were included. The endpoints were objective response rate (ORR), PFS, OS and safety in each group.

RESULTS

Of 200 patients with V600E (75%) or non-V600E (25%) mutant metastatic melanoma treated with BRAF/MEKi (median time of treatment 7.6 months; treatment cessation due to progressive disease in 77%), 115 (57.5%) had subsequent PD1 and 85 (42.5%) had IPI+PD1. Differences in patient characteristics between PD1 and IPI+PD1 groups included, age (med. 63 vs 54 years), time between BRAF/MEKi and PD1±IPI (16 vs 4 days), Eastern Cooperative Oncology Group Performance Status (ECOG PS) of ≥1 (62% vs 44%), AJCC M1C/M1D stage (72% vs 94%) and progressing brain metastases at the start of PD1±IPI (34% vs 57%). Median follow-up from PD1±IPI start was 37.8 months (95% CI, 33.9 to 52.9). ORR was 36%; 34% with PD1 vs 39% with IPI+PD1 (p=0.5713). Median PFS was 3.4 months; 3.4 with PD1 vs 3.6 months with IPI+PD1 (p=0.6951). Median OS was 15.4 months; 14.4 for PD1 vs 20.5 months with IPI+PD1 (p=0.2603). The rate of grade 3 or 4 toxicities was higher with IPI+PD1 (31%) vs PD1 (7%). ORR, PFS and OS were numerically higher with IPI+PD1 vs PD1 across most subgroups except for females, those with <10 days between BRAF/MEKi and PD1±IPI, and those with stage III/M1A/M1B melanoma. The combination of ECOG PS=0 and absence of liver metastases identified patients with >3 years OS (area under the curve, AUC=0.74), while ECOG PS ≥1, progressing brain metastases and presence of bone metastases predicted primary progression (AUC=0.67).

CONCLUSIONS

IPI+PD1 and PD1 after BRAF/MEKi have similar outcomes despite worse baseline prognostic features in the IPI+PD1 group, however, IPI+PD1 is more toxic. A combination of clinical factors can identify long-term survivors, but less accurately those with primary resistance to immunotherapy after targeted therapy.

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.

Combination targeted and immune therapy in the treatment of advanced melanoma: a valid treatment option for patients?

Melanomas harboring an activating BRAFV600 mutation account for 50% of all advanced melanomas. The approval of BRAF-targeted therapy revolutionized treatment of these patients with achievement of impressive responses. However, development of resistance to these drugs is a significant problem, and as such, duration of response remains low, with median progression free survival of around 11–15 months. Immune checkpoint blockers exploit the immune system to eradicate cancer and can produce durable disease control that results in long-term, treatment-free survival in some patients. These drugs have shown very impressive survival in patients with BRAF-mutated melanoma. Thus, there is a need to continue to utilize emerging data to achieve long-term disease control for patients with advanced melanoma. Combining targeted therapy with immune therapy may be one possible way to achieve this goal. In this review, the mechanisms of action of these two pathways, including the mechanistic basis of this combination, are summarized, along with results of completed and ongoing trials in triple therapy.

MAPKinase inhibition after failure of immune checkpoint blockade in patients with advanced melanoma - An evaluation of the multicenter prospective skin cancer registry ADOREG

OBJECTIVES

Forty to sixty percent of patients with advanced melanoma show primary resistance to PD-1-based immunotherapy, 30-40% of initial responders also progress. Here, we evaluated the outcome of second-line targeted therapy (TT) after progression on PD-1-based immune checkpoint inhibition (ICI) in BRAFV600-mutated melanoma. In addition, we report data on the activity of re-exposure with PD-1-based regimes.

METHODS

Patients with advanced (non-resectable stage III or IV, AJCC 2017, 8th edition) melanoma progressing on PD-1-based ICI (nivolumab, pembrolizumab or ipilimumab plus nivolumab) and receiving second-line BRAF plus MEK inhibition were identified from the prospective multicenter skin cancer registry ADOREG.

RESULTS

We identified 108 patients with unresectable stage III or stage IV melanoma progressing on first-line ICI (nivolumab, pembrolizumab or ipilimumab plus nivolumab) and receiving second-line combined BRAF/MEK inhibition. Seventy-three percent of the cohort presented with primary PD-1 resistant disease. Median progression-free survival (PFS) on ICI was 2.6 (95% CI 2.2-2.9) months. Median PFS on subsequent TT was 6.6 (95% CI 5.4-7.8) months. Median OS from start of second-line TT was 16.0 (95% CI 11.2-20.8) months. The 3-year PFS and OS rates on second-line TT were 16% and 30%. The objective response rate (ORR) and disease control rate (DCR) to TT were 42.6% and 55.6%. In patients with brain metastases, the ORR and DCR were 31.4% and 43.1%. Patients without brain metastases showed an ORR and DCR of 52.6% and 66.7%, respectively. Response to first-line ICI was associated with a numerically higher ORR and DCR to second-line TT and improved OS on TT. Twenty-three patients received third-line ICI of whom two patients showed an objective response.

CONCLUSIONS

BRAF plus MEK inhibition shows meaningful activity and outcome in patients with advanced melanoma resistant to anti-PD-1-based immunotherapy. Rates of long-term benefit and survival in our study were similar to those reported for treatment-naïve patients receiving first-line MAPKi.

Clinical Models to Define Response and Survival With Anti-PD-1 Antibodies Alone or Combined With Ipilimumab in Metastatic Melanoma

PURPOSE

Currently, there are no robust biomarkers that predict immunotherapy outcomes in metastatic melanoma. We sought to build multivariable predictive models for response and survival to anti-programmed cell death protein 1 (anti-PD-1) monotherapy or in combination with anticytotoxic T-cell lymphocyte-4 (ipilimumab [IPI]; anti-PD-1 ± IPI) by including routine clinical data available at the point of treatment initiation.

METHODS

One thousand six hundred forty-four patients with metastatic melanoma treated with anti-PD-1 ± IPI at 16 centers from Australia, the United States, and Europe were included. Demographics, disease characteristics, and baseline blood parameters were analyzed. The end points of this study were objective response rate (ORR), progression-free survival (PFS), and overall survival (OS). The final predictive models for ORR, PFS, and OS were determined through penalized regression methodology (least absolute shrinkage and selection operator method) to select the most significant predictors for all three outcomes (discovery cohort, N = 633). Each model was validated internally and externally in two independent cohorts (validation-1 [N = 419] and validation-2 [N = 592]) and nomograms were created.

RESULTS

The final model for predicting ORR (area under the curve [AUC] = 0.71) in immunotherapy-treated patients included the following clinical parameters: Eastern Cooperative Oncology Group Performance Status, presence/absence of liver and lung metastases, serum lactate dehydrogenase, blood neutrophil-lymphocyte ratio, therapy (monotherapy/combination), and line of treatment. The final predictive models for PFS (AUC = 0.68) and OS (AUC = 0.77) included the same variables as those in the ORR model (except for presence/absence of lung metastases), and included presence/absence of brain metastases and blood hemoglobin. Nomogram calculators were developed from the clinical models to predict outcomes for patients with metastatic melanoma treated with anti-PD-1 ± IPI.

CONCLUSION

Newly developed combinations of routinely collected baseline clinical factors predict the response and survival outcomes of patients with metastatic melanoma treated with immunotherapy and may serve as valuable tools for clinical decision making.

Predictive biomarkers for response to immune checkpoint inhibition

Immune checkpoint inhibitors have transformed the prognosis and treatment paradigm of many cancer types, through the potential for durable responses. However, the majority of patients still do not benefit. Response to checkpoint inhibition is determined by dynamic host, tumour and tumour microenvironment factors that display spatial and temporal variability, but our understanding of these interactions is incomplete. Through investigating biomarkers of resistance and response, opportunities arise to discover new therapeutic targets and shape personalised treatment strategies. Here we review approved and emerging biomarkers of response to immune checkpoint inhibitors, in particular the recent rapid progress in host and tumour genomics. It is unlikely that a single biomarker will precisely predict response, but multivariate multiomic markers may provide a balanced assessment of these factors and more accurately identify patients who will benefit. Further efforts are required to translate these groundbreaking discoveries into novel therapeutics and biomarker driven clinical trials, to provide durable treatment response to a greater population of patients.

Multiomic profiling of checkpoint inhibitor-treated melanoma: Identifying predictors of response and resistance, and markers of biological discordance

We concurrently examine the whole genome, transcriptome, methylome, and immune cell infiltrates in baseline tumors from 77 patients with advanced cutaneous melanoma treated with anti-PD-1 with or without anti-CTLA-4. We show that high tumor mutation burden (TMB), neoantigen load, expression of IFNγ-related genes, programmed death ligand expression, low PSMB8 methylation (therefore high expression), and T cells in the tumor microenvironment are associated with response to immunotherapy. No specific mutation correlates with therapy response. A multivariable model combining the TMB and IFNγ-related gene expression robustly predicts response (89% sensitivity, 53% specificity, area under the curve [AUC], 0.84); tumors with high TMB and a high IFNγ signature show the best response to immunotherapy. This model validates in an independent cohort (80% sensitivity, 59% specificity, AUC, 0.79). Except for a JAK3 loss-of-function mutation, for patients who did not respond as predicted there is no obvious biological mechanism that clearly explained their outlier status, consistent with intratumor and intertumor heterogeneity in response to immunotherapy.

Re-thinking therapeutic development for CNS metastatic disease

There has been unprecedented progress in the development of systemic therapies for patients with metastatic melanoma over the last decade. There is now tremendous potential and momentum to further and markedly reduce the impact of this disease. However, developing more effective treatments for metastases to the CNS remains a critical challenge for patients with melanoma. Melanoma patients with active CNS metastases have largely been excluded from both early-phase and registration trials for all currently approved targeted and immune therapies for this disease. While this exclusion has generally been justified in clinical research due to concerns about poor prognosis, lack of CNS penetration of agents and/or risk of toxicities, recent post-approval trials have shown the feasibility, safety and clinical benefit of clinical investigation in these patients. These trials have also identified key areas for which more effective strategies are needed. In parallel, recent translational and preclinical research has provided insights into novel immune, molecular and metabolic features of melanoma brain metastases that may mediate the aggressive biology and therapeutic resistance of these tumors. Together, these advances suggest the need for new paradigms for therapeutic development for melanoma patients with CNS metastasis.

Treatment beyond progression and locoregional approaches in selected patients with BRAF-mutated metastatic melanoma

The clinical management of BRAF-mutated metastatic melanoma had an important turning point after the introduction of the targeted therapy. Despite the efficacy and good tolerability of this treatment, the development of resistance mechanisms causes disease progression. The aim of this review is to investigate the role of treatment beyond progression and locoregional approaches in BRAF-mutated metastatic melanoma and provide oncologists dealing with this malignancy a useful road map on when and why to choose this strategy.

The article is structured in the form of a narrative review reporting the most significant studies on the subject. Most of the available articles are represented by retrospective studies and case reports, leading to limitations in the final interpretations. Nevertheless, a correct analysis of the selected studies allows the drawing of some conclusions. In well-selected cases, treatment beyond progression could play an important role in the treatment sequence of patients with BRAF-mutated advanced melanoma and would seem to produce good disease control rates and positive survival outcomes. A careful evaluation of the radiological examinations and laboratory tests, based on the clinical conditions, allows the identification of which patients can benefit from this strategy. Such patients are those who, at the time of progression, have favourable features such as a lower performance status according to Eastern Cooperative Oncology Group (ECOG-PS), normal lactate dehydrogenase levels and lower disease burden. The clinical benefit is also consolidated by the addition of locoregional approaches. Locoregional approaches can include electrochemotherapy, radiotherapy or surgery, and their use provides local disease control and a better quality of life for patients.

Impact of prior treatment with immune checkpoint inhibitors on dacarbazine efficacy in metastatic melanoma

BACKGROUND

Despite its low efficacy, chemotherapy with dacarbazine remains an option in metastatic melanoma patients after failure of immune checkpoint inhibitors (ICI) ± targeted therapy. Some observations suggested an increased efficacy of chemotherapy in melanoma or lung cancer patients previously treated with ICI; we aimed to evaluate the efficacy of dacarbazine in a controlled-group study of patients pre-treated or not with ICI.

METHODS

We retrospectively collected data from all consecutive patients treated with dacarbazine for advanced cutaneous melanoma without brain metastasis, in our skin cancer centre between June 2006 and September 2019. The primary endpoint was progression-free survival (PFS); secondary endpoints were overall response rates (ORR), overall survival (OS) and safety of dacarbazine.

RESULTS

Among 72 patients, 17 (23.6%) received dacarbazine after ICI and 55 (76.3%) without prior ICI. Despite less favourable prognostic factors in patients ICI-pre-treated, median PFS was 4.27 months (range 0.89-43.69) in this group versus 2.04 months (range 1.25-39.25) P = 0.03 in non-ICI-pre-treated patients; ORR were 35.3% and 12.7%, respectively. The median OS and the occurrence of adverse events were similar in both groups.

CONCLUSION

Dacarbazine seems to offer a short-lived benefit in patients with progressive advanced disease despite ICI (±targeted therapy), and could be an alternative before considering best supportive care.

Treatment Following Progression in Metastatic Melanoma: the State of the Art from Scientific Literature to Clinical Need

INTRODUCTION

In the last few years, the advent of targeted therapy and immunotherapy has improved the management and the prognosis of metastatic melanoma, but the spread of resistance mechanisms can lead to disease progression. The clinical management in this setting can be challenging because the oncologist has to decide what is the best treatment strategy among therapy beyond progression (TBP), therapy change, and the rechallenge approach. This review of the relevant scientific literature is intended to clarify which patients with progressing metastatic melanoma will benefit from continuation of ongoing therapy and which ones will not. The data are based on a total of about 4300 patients coming from the main retrospective studies in the chosen field. The article body is divided into four sections which analyze respectively the targeted therapy beyond progression, the immunotherapy beyond progression, the possible treatment sequences, and finally the rechallenge strategy.

RECENT FINDINGS

Despite the possible approaches of TBP or rechallenge, the patient may not have an optimal response and may need new therapy, which is currently missing. To broaden the pharmacological offer in the fight against melanoma, cancer research is studying new disease targets, like the NRAS, PI3K, and cKIT pathways or combination treatment of targeted therapy plus immunotherapy. Despite the limitations of this work, mainly due to the limited number of studies, their retrospective nature and the lack of comparative studies, the analysis performed allows us to draw some important conclusions: therapy beyond progression, both targeted therapy and immunotherapy, represents a valid treatment option with positive effects on disease control and survival outcomes for patients with low clinical risk, expressed as low disease burden, normal LDH levels, and good performance status; moreover, the prognosis and quality of life of these patients improve when TBP is associated with locoregional treatments. In patients with progressive metastatic melanoma and high clinical risk (high disease burden, high LDH levels, and poor performance status), it is recommended to change therapy, without ever forgetting the possibility of enrolling the patient in a clinical trial. Finally, an efficacious treatment alternative is the rechallenge strategy; this approach consists in a re-treatment with the same drug after a variable interval of discontinuation. Preliminary studies seem to have demonstrated that patients retreated with targeted therapy achieved a greater benefit if they had a low clinical risk and if the drug doublet (BRAF + MEK inhibitors) was used. On the side of immunotherapy, the rechallenge strategy produced a major benefit in patients who prior experienced a severe toxic episode.

Discontinuation of BRAF/MEK-Directed Targeted Therapy after Complete Remission of Metastatic Melanoma-A Retrospective Multicenter ADOReg Study

The advent of BRAF/MEK inhibitors (BRAFi/MEKi) has significantly improved progression-free (PFS) and overall survival (OS) for patients with advanced BRAF-V600-mutant melanoma. Long-term survivors have been identified particularly among patients with a complete response (CR) to BRAF/MEK-directed targeted therapy (TT). However, it remains unclear which patients who achieved a CR maintain a durable response and whether treatment cessation might be a safe option in these patients. Therefore, this study investigated the impact of treatment cessation on the clinical course of patients with a CR upon BRAF/MEK-directed-TT. We retrospectively selected patients with BRAF-V600-mutant advanced non-resectable melanoma who had been treated with BRAFi ± MEKi therapy and achieved a CR upon treatment out of the multicentric skin cancer registry ADOReg. Data on baseline patient characteristics, duration of TT, treatment cessation, tumor progression (TP) and response to second-line treatments were collected and analyzed. Of 461 patients who received BRAF/MEK-directed TT 37 achieved a CR. TP after initial CR was observed in 22 patients (60%) mainly affecting patients who discontinued TT (n = 22/26), whereas all patients with ongoing TT (n = 11) maintained their CR. Accordingly, patients who discontinued TT had a higher risk of TP compared to patients with ongoing treatment (p < 0.001). However, our data also show that patients who received TT for more than 16 months and who discontinued TT for other reasons than TP or toxicity did not have a shorter PFS compared to patients with ongoing treatment. Response rates to second-line treatment being initiated in 21 patients, varied between 27% for immune-checkpoint inhibitors (ICI) and 60% for BRAFi/MEKi rechallenge. In summary, we identified a considerable number of patients who achieved a CR upon BRAF/MEK-directed TT in this contemporary real-world cohort of patients with BRAF-V600-mutant melanoma. Sustained PFS was not restricted to ongoing TT but was also found in patients who discontinued TT.

Inflammation and Apolipoproteins Are Potential Biomarkers for Stratification of Cutaneous Melanoma Patients for Immunotherapy and Targeted Therapy

Malignant cutaneous melanoma is one of the most common cancers in young adults. During the last decade, targeted and immunotherapies have significantly increased the overall survival of patients with malignant cutaneous melanoma. Nevertheless, disease progression is common, and a lack of predictive biomarkers of patient response to therapy hinders individualized treatment strategies. To address this issue, we performed a longitudinal study using an unbiased proteomics approach to identify and quantify proteins in plasma both before and during treatment from 109 patients treated with either targeted or immunotherapy. Linear modeling and machine learning approaches identified 43 potential prognostic and predictive biomarkers. A reverse correlation between apolipoproteins and proteins related to inflammation was observed. In the immunotherapy group, patients with low pretreatment expression of apolipoproteins and high expression of inflammation markers had shorter progression-free survival. Similarly, increased expression of LDHB during treatment elicited a significant impact on response to immunotherapy. Overall, we identified potential common and treatment-specific biomarkers in malignant cutaneous melanoma, paving the way for clinical use of these biomarkers following validation on a larger cohort. SIGNIFICANCE: This study identifies a potential biomarker panel that could improve the selection of therapy for patients with cutaneous melanoma.

Thinking Small: Small Molecules as Potential Synergistic Adjuncts to Checkpoint Inhibition in Melanoma

Metastatic melanoma remains the deadliest form of skin cancer. Immune checkpoint inhibition (ICI) immunotherapy has defined a new age in melanoma treatment, but responses remain inconsistent and some patients develop treatment resistance. The myriad of newly developed small molecular (SM) inhibitors of specific effector targets now affords a plethora of opportunities to increase therapeutic responses, even in resistant melanoma. In this review, we will discuss the multitude of SM classes currently under investigation, current and prospective clinical combinations of ICI and SM therapies, and their potential for synergism in melanoma eradication based on established mechanisms of immunotherapy resistance.

Mechanisms of Resistance to BRAF-Targeted Melanoma Therapies

About half of all cutaneous melanomas harbor activating mutations in the BRAF oncogene. Dependence on this pathway makes the tumors vulnerable to BRAF (and downstream MEK) inhibition, and three drug combinations are approved to target this vulnerability in advanced melanomas with BRAFV600 mutations. Responses to BRAF/MEK inhibitors are usually fast, but durability of response can be limited. Five-year data from BRAF/MEK inhibitors show long-term survival benefit for a third of the patients. There is a wide variety of known mechanisms of resistance to BRAF/MEK inhibition, such as mitogen-activated protein kinase reactivation, activation of parallel pathways, alterations in cell-cycle regulation, and non-genetic resistance mechanisms. Strategies that have been explored to overcome these mechanisms include alternative dosing regimens, addition of another kinase inhibitor, and use of anti-PD-1 immunotherapy either in combination or post-relapse on BRAF/MEK inhibitor therapies.

First-line immunotherapy versus targeted therapy in patients with BRAF-mutant advanced melanoma: a real-world analysis

Aim: To compare effectiveness of nivolumab + ipilimumab (NIVO + IPI) versus BRAF + MEK inhibitors (BRAFi + MEKi) in patients with BRAF-mutant advanced melanoma in the real-world setting. Materials & methods: This study used the Flatiron Health electronic medical record database. Results: After adjusting for differences in baseline characteristics, NIVO + IPI was associated with a 32% reduction in risk of death versus BRAFi + MEKi. At a mean follow-up of 15-16 months, 64% of NIVO + IPI patients and 43% of BRAFi + MEKi patients were alive; subsequent therapy was administered to 33 and 41% of patients, respectively. After first-line NIVO + IPI, 20% of patients died before subsequent therapy, whereas 32% died after first-line BRAFi + MEKi. Conclusion: In this real-world study, patients treated with first-line NIVO + IPI showed significant survival benefit versus those receiving first-line BRAFi + MEKi.

Treatment of Advanced Melanoma: Past, Present and Future

Therapeutic options for treating advanced melanoma are progressing rapidly. Until six years ago, the regimen for treating advanced melanoma mainly comprised cytotoxic agents such as dacarbazine, and type I interferons. Since 2014, anti-programmed cell death 1 (PD1) antibodies have become recognized as anchor drugs for treating advanced melanoma with or without additional combination drugs such as ipilimumab. In addition, v-Raf murine sarcoma viral oncogene homolog B1 (BRAF) kinase inhibitors in combination with mitogen-activated protein kinase kinase (MEK) inhibitors are among the most promising chemotherapeutic regimens for treating advanced BRAF-mutant melanoma, especially in patients with low tumor burden. Since anti-PD1 antibodies are widely applicable for the treatment of both BRAF wild-type and mutated advanced melanomas, several clinical trials for drugs in combination with anti-PD1 antibodies are ongoing. This review focuses on the development of the anti-melanoma therapies available today, and discusses the clinical trials of novel regimens for the treatment of advanced melanoma.

Hyperprogressive disease rarely occurs during checkpoint inhibitor treatment for advanced melanoma

Introduction

Hyperprogression, characterized by a rapid acceleration in tumor growth, is a novel pattern of progression recently described in patients treated with immune checkpoint inhibitors. This study aims to assess the incidence of hyperprogression in patients with advanced melanoma treated with checkpoint inhibitors.

Methods

Clinical and radiological findings of all advanced melanoma patients who started checkpoint inhibitors between January 2013 and March 2019 in a tertiary academic center in the Netherlands were analyzed. Change in tumor burden was calculated by assessing volumetric tumor growth using the criteria as defined by immune Response Evaluation Criteria in Solid Tumors version 1.1. Hyperprogression was defined as a time to treatment failure less than 2 months with doubling of tumor burden and a twofold increase in tumor growth rate during treatment. Possible hyperprogression was defined as the presence of the first two criteria in the absence of a pre-baseline scan.

Results

Out of 206 treatment episodes in 168 patients, 75 were evaluable for hyperprogression and 87 for possible hyperprogression. Hyperprogression was observed in one patient (1.3%) and possible hyperprogression was observed in one patient (1.1%).

Conclusion

Hyperprogression is rare in melanoma patients treated with immune checkpoint inhibitors. Our data question if hyperprogression really is a biological entity in metastatic melanoma.

Targeted and immunotherapies in BRAF mutant melanoma: where we stand and what to expect

The therapeutic landscape for melanoma has evolved drastically in the past decade. Currently, immune checkpoint inhibitors and small-molecule inhibitors targeting the mitogen-activated protein kinase (MAPK) pathway are the two mainstay therapies for BRAF^V600 mutant advanced melanoma. Although MAPK dependence has been variably demonstrated in melanomas lacking BRAF^V600 mutations, definitive evidence of benefit with MAPK inhibitors has not been demonstrated. Thus, in the BRAF^V600 'wild-type' setting, immune checkpoint inhibitors are the standalone option(s). In the BRAF^V600 mutant setting, there is no definitive evidence prioritizing one therapeutic modality over another. Herein, we review the updated data of the pivotal phase III randomized controlled trials that established the standard-of-care first-line treatment for advanced melanoma, as it provides insights into long-term benefit, which is a major factor in therapy selection. We discuss the clinical considerations for choosing between these therapies in the front-line setting and beyond, specifically for patients with BRAF^V600 mutant melanoma based on currently available evidence. We have previously proposed a time-dependent resistance paradigm in which future therapeutic development strategies can be rooted. We also discuss how these Food and Drug Administration (FDA)-approved therapeutic modalities are being pursued earlier in the course of disease management, namely in adjuvant and neoadjuvant settings. FDA-approved interlesional oncolytic virotherapy in the modern era is also briefly discussed.

Long-Term Outcomes in BRAF-Mutated Melanoma Treated with Combined Targeted Therapy or Immune Checkpoint Blockade: Are We Approaching a True Cure?

Approximately 50% of all melanomas harbor an activating BRAF mutation. In patients suffering from an advanced melanoma with such a somatic alteration, combined targeted therapy with a BRAF and MEK inhibitor can be applied to significantly increase the survival probability. Nevertheless, resistance mechanisms, as well as negative predictive biomarkers (elevated lactate dehydrogenase levels, high number of metastatic organ disease sites, brain metastasis), remain a major problem in treating melanoma patients. Recently, a landmark overall survival (OS) rate of 34% after 5 years of combined targeted therapy in treatment-naïve patients was reported. On the other hand, patients harboring a BRAF mutation and receiving first-line immune checkpoint blockade with ipilimumab plus nivolumab showed a 5-year OS rate of 60%. As indicated by these data, long-term survival can be reached in melanoma patients but it remains unclear if this is equivalent to reaching a true cure for metastatic melanoma. In this review, we summarize the recent results for combined targeted therapy and immunotherapy in advanced melanoma harboring an activating BRAF mutation and discuss the impact of baseline characteristics on long-term outcome.

Preclinical discovery and clinical development of encorafenib for the treatment of melanoma

INTRODUCTION

Nearly 50% of patients with metastatic melanoma harbor a BRAFV600-mutation, which can be targeted with the use of BRAF and MEK inhibitors, either in the front-line or treatment-refractory setting. Encorafenib is the newest BRAF-inhibitor to have received FDA-approval in combination with the MEK inhibitor binimetinib.

AREAS COVERED

The authors provide an overview of the preclinical development and the clinical trials that led to the use of encorafenib in BRAFV600-mutant melanoma. They also give discussion on its current use in clinical practice, providing their expert perspectives on the subject.

EXPERT OPINION

Preclinical research has provided strong rationale for upgrading encorafenib investigation into clinical development/testing. However, there is not yet enough data to determine where encorafenib may fit in comparison to other drugs in the same class, and ongoing trials will further define its role in the treatment of melanoma. Of note, there are ongoing studies that further explore the role of encorafenib + binimetinib such as in combination regimens with immunotherapy drugs, and in brain metastases.

The efficacy and safety of combined immune checkpoint inhibitors (nivolumab plus ipilimumab): a systematic review and meta-analysis

BACKGROUND

Currently, nivolumab and ipilimumab are the most widely used immune checkpoint inhibitors. We performed a meta-analysis to evaluate the efficacy and treatment-related adverse events (TRAEs) of nivolumab plus ipilimumab therapy in cancer treatment.

METHODS

We examined data from PubMed, Web of Science, EBSCO, and Cochrane Library. Eleven articles fulfilled our criteria, which we divided into 3 groups: nivolumab plus ipilimumab versus nivolumab (the dose used for monotherapy is 3 mg/kg), nivolumab plus ipilimumab versus ipilimumab (the dose used for monotherapy is 3 mg/kg), and nivolumab 1 mg/kg plus ipilimumab 3 mg/kg (N1I3) versus nivolumab 3 mg/kg plus ipilimumab 1 mg/kg (N3I1). We measured the complete response (CR), partial response (PR), objective response rate (ORR), and TRAEs in any grade and grade 3 or higher.

RESULTS

The overall effect estimate favored the combined immunotherapy group in terms of the ORR (RR: 1.40, p < 0.001) and PR (RR: 1.50, p < 0.001) than nivolumab alone. Compared with ipilimumab alone, the combined immunotherapy group had better CR (RR: 4.89, p < 0.001), PR (RR: 2.75, p < 0.001), and ORR (RR: 3.31, p < 0.001). Finally, N1I3 showed better PR (RR: 1.35, p = 0.006) and ORR (RR: 1.21, p = 0.03) than N3I1. The incidence of any TRAEs was similar between both groups (RR: 1.05, p = 0.06). However, the incidence of serious adverse events (grade 3 or higher) was lower in group N3I1 than group N1I3 (RR: 1.51, p < 0.001).

CONCLUSION

This meta-analysis showed that the curative effect of nivolumab plus ipilimumab was better than that of nivolumab or ipilimumab monotherapy. In the combined immunotherapy group, N1I3 was more effective than N3I1. Although the side effects were slightly increased in N1I3 group, overall safety was acceptable.

Immune checkpoint blockade in solid organ tumours: Choice, dose and predictors of response

Immune checkpoint blockade has transformed outcomes across solid organ tumours. Monoclonal antibodies targeting the negative inhibitory cytotoxic T lymphocyte-associated protein 4 and programmed-death 1/programmed death-ligand 1 axis can lead to deep and durable responses across several tumour streams in the advanced setting. This immunotherapy approach is increasingly used earlier in the treatment paradigm. A rapidly evolving regulatory, reimbursement and drug development landscape has accompanied this novel class of immunotherapy. Unfortunately, only a small proportion of patients respond meaningfully to these agents. Here we review how the underlying tumoural genomic, histological and immunological characteristics interact within various patient phenotypes, leading to variations in response to checkpoint blockade. Concurrently, we outline the clinical trial and real-world evidence that allows for appropriate selection of agent, dose and schedule in solid organ malignancies. An exploration of current trends in basic and translational research in immune checkpoint blockade accompanies a commentary on future clinical directions for checkpoint blockade in oncology.

Switch to checkpoint inhibition after targeted therapy at time of progression or during ongoing response: A retrospective single-centre experience in patients with BRAF-mutated melanoma

BRAF + MEK inhibition is preferentially applied as first-line therapy in BRAF V600-mutated melanoma patients with unfavourable prognostic features, due to the ability of targeted therapy (TT) to induce rapid symptom control, decrease tumour burden and normalize lactate dehydrogenase (LDH) levels. In addition, short-term TT transiently increases tumour antigen presentation and tumour influx of T cells. Therefore, it might be favourable to switch TT to checkpoint inhibition (CPI) before progression (PD). We retrospectively analysed melanoma patients treated first line with TT (TT1) and who subsequently switched to CPI during response to TT (sDR group) or at progression upon TT (sPD group). We identified 74 patients (n = 37 sDR group and n = 37 sPD group). ORR to CPI was 27.0% in the sDR group versus 24.3% in the sPD group (p = .790). Median was PFS 2.5 months versus 1.2 months (p = .145), and median OS was 30.6 versus 14.1 months (p = .007). After adjusting for baseline differences and known prognostic factors, hazard ratios (HRs) favouring sDR were 0.89 for PFS upon CPI (p = .956) and 0.48 for OS (p = .055). Thus, patients switching to CPI during ongoing clinical benefit from TT do not have an inferior outcome. Due to baseline imbalances and small patient population, a favourable trend for the sDR group can be hypothesized only.

Real-world survival of patients with advanced BRAF V600 mutated melanoma treated with front-line BRAF/MEK inhibitors, anti-PD-1 antibodies, or nivolumab/ipilimumab

BACKGROUND

The optimal treatment sequence for patients with advanced BRAF V600 mutant melanoma is unknown. BRAF/MEK inhibition (BRAF/MEKi), single agent anti-PD-1 (aPD-1) antibodies and combination immune checkpoint inhibition with nivolumab and ipilimumab (niv/ipi) are all approved; however, they have not been prospectively compared. Therefore, we sought to compare overall survival of patients with advanced BRAF mutant melanoma treated with either front-line BRAF/MEKi, aPD-1, or niv/ipi.

METHODS

Patients with advanced BRAF mutant melanoma who had received BRAF/MEKi, niv/ipi, or aPD-1 in the front-line setting were identified from a nationwide database comprising de-identified patient-level structured and unstructured data derived from electronic health records. Survival was compared using Kaplan-Meier curves and log-rank analysis. Univariate and multivariate Cox regression models were used to measure the effect of front-line treatment, age (>64 or not), LDH (elevated or not), and Eastern Cooperative Oncology Group (ECOG) performance status (>1 or not) on survival.

RESULTS

Five hundred and sixty seven patients with advanced disease and treated with front-line aPD-1 (n = 162), BRAF/MEKi (n = 297) or niv/ipi (n = 108) were identified. With a median follow-up of 22.4 months, median overall survival (OS) for patients treated with front-line niv/ipi was not reached (NR) while median OS for patients treated with aPD-1 or BRAF/MEKi was 39.5 months and 13.2 months, respectively. Front-line treatment with PD-1 and niv/ipi were associated with statistically longer survival than BRAF/MEKi in multivariate analyses.

CONCLUSIONS

In our real-world retrospective analysis, patients with advanced BRAF mutant melanoma treated with front-line niv/ipi or aPD-1 had longer survival compared to those treated with front-line BRAF/MEKi.