Combination of dabrafenib plus trametinib for BRAF and MEK inhibitor pretreated patients with advanced BRAFV600-mutant melanoma: an open-label, single arm, dual-centre, phase 2 clinical trial

Circulating tumor DNA monitoring in advanced mutated melanoma (LIQUID-MEL)

Introduction

Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of metastatic melanoma, but a percentage of patients did not show benefit. Circulating tumor DNA (ctDNA) has emerged as a potential non-invasive tool for monitoring disease evolution and treatment response. The present study aimed to evaluate the clinical utility of ctDNA dynamics in patients with metastatic melanoma receiving ICIs, while exploring its role in the oncological course.

Materials and methods

The LIQUID-MEL study is a prospective, single-centre pilot study including patients with BRAF/NRAS-mutant metastatic melanoma. ctDNA was quantified using digital droplet PCR (ddPCR) at four different time points. Uni- and multivariable Cox regression models were used to assess the correlation between shedding and progression-free survival (PFS), and overall survival (OS).

Results

Overall, 23 patients were included. At baseline, ctDNA was detectable in 5/23 (21.7 %) cases. Baseline ctDNA shedding was associated with shorter PFS (3.88 months vs. 0.69 months, p=0.012). A strong numerical trend was observed also in OS (12.66 months vs. 2.53 months, p=0.287). Shedding at baseline did not demonstrate independent prognostic or predictive value in the uni- and multivariable analysis. The longitudinal analysis revealed intriguing patterns of ctDNA shedding in individual patients.

Conclusion

ctDNA detectability and its dynamic changes during treatment may have potential clinical utility in patients with metastatic melanoma, offering a valuable non-invasive tool for monitoring disease and treatment response. The small sample size limited the statistical power of the analysis. Further studies with larger cohorts are needed to validate its role in routine clinical practice.

Rechallenge of ipilimumab and nivolumab in advanced melanoma patients after previous ipilimumab-based therapy

BACKGROUND

Ipilimumab+nivolumab (IPINIVO) can induce durable responses in advanced melanoma, but many patients experience progression at some point. It is currently unknown to what extent these patients benefit from IPINIVO rechallenge. This study describes efficacy and safety of IPINIVO rechallenge.

METHODS

Data from advanced melanoma patients rechallenged with IPINIVO after previous ipilimumab-containing treatment were retrieved from the nationwide Dutch Melanoma Treatment Registry. Patient characteristics, responses, survival, and safety were analyzed.

RESULTS

Among 3.759 patients receiving ipilimumab-containing treatment, 73 received rechallenge IPINIVO. 41 received IPINIVO, 32 ipilimumab monotherapy (IPI) as initial therapy. Objective response to rechallenge IPINIVO was seen in 36.1% (initial IPINIVO) and 40.0% (initial IPI) of patients. Median progression-free survival after rechallenge was 2.8 months (initial IPINIVO) and 5.6 months (initial IPI), but reached 18.4 months for responders to rechallenge therapy. Grade ≥3 immune-related adverse events occurred in 40.5% (initial IPINIVO) and 38.7% (initial IPI) of patients. Objective responses to initial and rechallenge treatment were discordant in 48.6% (initial IPINIVO) and 53.3% (initial IPI) of patients. Fifteen patients (20.5%) responded to rechallenge therapy but not to initial treatment.

CONCLUSIONS

Rechallenge IPINIVO after previous ipilimumab-based therapy had a considerable response rate, acceptable safety profile, and potential for a durable response.

Integrating bioinformatics and machine learning to identify AhR-related gene signatures for prognosis and tumor microenvironment modulation in melanoma

Background

The Aryl Hydrocarbon Receptor (AhR) pathway significantly influences immune cell regulation, impacting the effectiveness of immunotherapy and patient outcomes in melanoma. However, the specific downstream targets and mechanisms by which AhR influences melanoma remain insufficiently understood.

Methods

Melanoma samples from The Cancer Genome Atlas (TCGA) and normal skin tissues from the Genotype-Tissue Expression (GTEx) database were analyzed to identify differentially expressed genes, which were intersected with a curated list of AhR-related pathway genes. Prognostic models were subsequently developed, and feature genes were identified. Advanced methodologies, including Gene Set Enrichment Analysis (GSEA) and immune cell infiltration analysis, were employed to explore the biological significance of these genes. The stability of the machine learning models and the relationship between gene expression and immune infiltrating cells were validated using three independent melanoma datasets. A mouse melanoma model was used to validate the dynamic changes of the feature genes during tumor progression. The relationship between the selected genes and drug sensitivity, as well as non-coding RNA interactions, was thoroughly investigated.

Results

Our analysis identified a robust prognostic model, with four AhR-related genes (MAP2K1, PRKACB, KLF5, and PIK3R2) emerging as key contributors to melanoma progression. GSEA revealed that these genes are involved in primary immunodeficiency. Immune cell infiltration analysis demonstrated enrichment of CD4+ naïve and memory T cells, macrophages (M0 and M2), and CD8+ T cells in melanoma, all of which were associated with the expression of the four feature genes. Importantly, the diagnostic power of the prognostic model and the relevance of the feature genes were validated in three additional independent melanoma datasets. In the mouse melanoma model, Map2k1 and Prkacb mRNA levels exhibited a progressive increase with tumor progression, supporting their role in melanoma advancement.

Conclusions

This study presents a comprehensive analysis of AhR-related genes in melanoma, highlighting MAP2K1, PRKACB, KLF5, and PIK3R2 as key prognostic markers and potential therapeutic targets. The integration of bioinformatics and machine learning provides a robust framework for enhancing prognostic evaluation in melanoma patients and offers new avenues for the development of treatments, particularly for those resistant to current immunotherapies.

Anti-Tumor Effects of Sheep Umbilical Cord Mesenchymal Stem Cells on Melanoma Cells

Melanoma is among the most common malignancies and has recently exhibited increased resistance to treatments, resulting in a more aggressive disease course. Mesenchymal stem cells (MSCs) secrete cytokines both in vivo and in vitro, which regulate tumor cell signaling pathways and the tumor microenvironment, thereby influencing tumor progression. This study investigates the anti-melanogenesis effects of sheep umbilical cord mesenchymal stem cells (SUCMSCs) to assess their potential application in melanoma treatment. Our findings indicate that, in vitro, SUCMSCs reduce melanin content and tyrosinase activity, inhibit melanoma cell viability, proliferation, migration, and invasion, and promote melanoma cell apoptosis. Subsequent in vivo experiments confirmed that SUCMSCs effectively suppress tumor growth, and histological analysis via HE staining revealed notable differences. Additionally, transcriptome sequencing analysis indicated that the anti-tumor effects were primarily mediated through autophagy, apoptosis, and the TGF-β and NF-κB signaling pathways. The RT-qPCR validation results aligned with the transcriptome data. In summary, SUCMSCs exert anti-melanogenesis effects through the interaction of multiple signaling pathways and cytokines, demonstrating significant potential for melanoma treatment.

Regorafenib Combined with BRAF/MEK Inhibitors for the Treatment of Refractory Melanoma Brain Metastases

BACKGROUND

There are no active treatment options for patients with progressive melanoma brain metastases (MBM) failing immune checkpoint blockade (ICB) and BRAF/MEK inhibitors (BRAF/MEKi). Regorafenib (REGO), an oral multi-kinase inhibitor (incl. RAF-dimer inhibition), can overcome adaptive resistance to BRAF/MEKi in preclinical models.

METHODS

This is a single-center retrospective case series of patients with refractory MBM treated with REGO plus BRAF/MEKi (compassionate use).

RESULTS

A total of 22 patients were identified (18 BRAF-mutant, 4 NRASQ61-mutant; 19 with progressive MBM; 11 on corticosteroids). Thirteen BRAFV600-mutant patients were progressing on BRAF/MEKi at the time of REGO association. BRAF-mutant patients received REGO (40-80 mg once daily) combined with BRAF/MEKi, NRAS-mutant patients were treated with REGO + MEKi (+low-dose BRAFi to mitigate skin-toxicity). Grade 3 TRAE included arterial hypertension (n = 4) and maculopapular rash (n = 3). There were no G4/5 TRAE. In BRAF-mutant patients, overall and intracranial objective response rates (overall ORR and IC-ORR) were 11 and 29%, and overall and intracranial disease control rates (overall DCR and IC-DCR) were 44 and 59%, respectively. In NRAS-mutant patients overall ORR and IC-ORR were 0 and 25% and overall DCR and IC-DCR were 25 and 50%, respectively. The median PFS and OS were, respectively, 7.1 and 16.4 weeks in BRAF-mutant and 8.6 and 10.1 weeks in NRAS-mutant patients.

CONCLUSIONS

In heavily pretreated patients with refractory MBM, REGO combined with BRAF/MEKi demonstrated promising anti-tumor activity with an acceptable safety profile. In BRAFV600-mutant melanoma patients, responses cannot solely be attributed to BRAF/MEKi rechallenge. Further investigation in a prospective trial is ongoing to increase understanding of the efficacy.

MEK inhibitor trametinib combined with PI3K/mTOR inhibitor BEZ-235 as an effective strategy against NSCLC through impairment of glucose metabolism

The MAPK and PI3K/AKT/mTOR pathways are aberrantly activated in non-small cell lung cancer (NSCLC) patients, but therapeutic efficacy of NSCLC using trametinib (MEK inhibitor) or BEZ-235 (dual PI3K/mTOR inhibitor) alone is still unsatisfactory. Therefore, in this study, we aimed to determine whether the combination of trametinib with BEZ-235 exerted synergistic effects against NSCLC in both in vitro and in vivo models, and we preliminarily explored the effect of this combination therapy on glucose metabolism. Our results showed that trametinib combined with BEZ-235 could better inhibit cell proliferation and colony formation, induce G0/G1 phase arrest and apoptosis, and suppress cell invasion and migration compared with the single agent. The combination index demonstrated that trametinib and BEZ-235 exerted strong synergistic effects. Additionally, trametinib and BEZ-235 exhibited synergistic antitumor effects in vivo. Furthermore, trametinib and BEZ-235 synergistically downregulated the expression of related proteins in the MAPK and PI3K/AKT/mTOR pathways, and decreased glucose consumption and lactic acid production through suppressing the expressions of glucose transporter 1 (GLUT1) and lactate dehydrogenase A (LDHA). These data imply that simultaneous inhibition of the MAPK and PI3K/AKT/mTOR pathways using trametinib combined with BEZ-235 could synergistically impair glucose metabolism, resulting in an obvious synergistic therapeutic effect against NSCLC.

Good response of stage IV melanoma to high‑dose radiation therapy combined with immunotherapy: A case report

Patients with advanced malignant melanoma (MM) often do not receive satisfactory treatment. The present study reports the case of a 51-year-old female patient with stage IV MM of unknown primary. After undergoing immune checkpoint inhibitor therapy, the patient received multiple doses of hypofractionated radiotherapy (HFRT) for the left inguinal lymph node and single-fraction high-dose-rate brachytherapy for the left and right lung metastases. After combination treatment, the patient experienced almost complete remission of the inguinal target area, significant relief of pain and discomfort and an improved quality of life. The time of lung radiotherapy lesion control was 8 months. Meanwhile, the observed lesions (observation lesions 1, 2, 3 and 5) adjacent to the target lesion received lower doses of scattering (0.9-1.8 Gy) and the time of control for these lung observation lesions was 9 months. In addition, restarting targeted therapy after cessation of other treatments due to myelosuppression resulted in a progression-free survival time of 6 months. Nevertheless, the patient developed new metastases in the brain and abdomen. The present case report demonstrates that high-dose radiotherapy combined with immunotherapy may be effective for local lesions and that multiple doses of HFRT may be superior to single-fraction high-dose-rate brachytherapy for certain patients. Low-dose scattering also shows improvement for local lesions. Furthermore, restarting targeted therapy may be effective in the presence of target sites. Thus, the present case report provides a possible therapeutic option for the treatment of advanced melanoma.

Redefining pancreatic cancer management with tumor-agnostic precision medicine

Precision oncology and tumor-agnostic drug development provide hope for enhancing outcomes among patients with pancreatic cancer. Tumor-agnostic therapies have emerged across various tumor types, driven by insights into shared biomarkers. In the case of pancreatic cancer, the prevalence of the KRAS gene mutation is noteworthy. However, there exist other actionable alterations, such as BRCA1/2 mutations and fusion genes (BRAF, FGFR2, RET, NTRK, NRG1, and ALK), which present potential targets for therapy. Notably, tumor-agnostic drugs have demonstrated efficacy in specific subsets of pancreatic cancer patients who harbor these genetic alterations. Despite the rarity of NTRK fusions in pancreatic cancer, larotrectinib and entrectinib have exhibited effectiveness in NTRK fusion-positive pancreatic cancers. Additionally, repotrectinib, a next-generation NTRK inhibitor, has shown promising activity in NTRK positive pancreatic cancer patients who have developed acquired resistance to previous NTRK inhibitors. Immune checkpoint inhibitors, such as pembrolizumab and dostarlimab, have proven to be effective in dMMR/MSI-H pancreatic cancers. Moreover, targeted therapies for BRAF V600, RET fusions, and HER2/neu overexpression have displayed promising results in specific subsets of pancreatic cancer patients. Emerging targets like NRG fusions, FGFR2 fusions, TP53 mutations, and KRAS G12C mutations present potential avenues for targeted therapy. Tumor-agnostic therapies have the potential to revolutionize pancreatic cancer treatment by focusing on specific genetic alterations. It is crucial to continue implementing comprehensive screening strategies that encompass the ability to detect all these tumor-agnostic biomarkers. This will be essential in identifying pancreatic cancer patients who may benefit from these therapies.

Inhibition of an Alzheimer's disease-associated form of necroptosis rescues neuronal death in mouse models

Necroptosis is a regulated form of cell death that has been observed in Alzheimer's disease (AD) along with the classical pathological hallmark lesions of amyloid plaques and Tau neurofibrillary tangles. To understand the neurodegenerative process in AD, we studied the role of necroptosis in mouse models and primary mouse neurons. Using immunohistochemistry, we demonstrated activated necroptosis-related proteins in transgenic mice developing Tau pathology and in primary neurons from amyloid precursor protein (APP)-Tau double transgenic mice treated with phosphorylated Tau seeds derived from a patient with AD but not in APP transgenic mice that only exhibited β-amyloid deposits. Necroptosis proteins in granulovacuolar degeneration (GVD) bodies were associated with neuronal loss in mouse brain regions also known to be vulnerable to GVD in the human AD brain. Necroptosis inhibitors lowered the percentage of neurons showing GVD and reduced neuronal loss, both in transgenic mice and in primary mouse neurons. This suggests that a GVD-associated form of necroptosis that we refer to as "GVD-necroptosis" may represent a delayed form of necroptosis in AD. We propose that inhibition of necroptosis could rescue this type of neuronal death in AD.

Rapid but nondurable response of a BRAF exon 15 double-mutated spindle cell sarcoma to a combination of BRAF and MEK inhibitors

INTRODUCTION

BRAF V600E substitution predicts sensitivity of a cancer to BRAF inhibitor therapy. The mutation is rarely found in soft-tissue sarcomas. Here we describe a case of undifferentiated spindle cell sarcoma showing primary insensitivity to standard chemotherapy and pronounced but non-sustained response to BRAF/MEK inhibitors at recurrence.

CASE PRESENTATION

A 13-year-old girl was diagnosed with low-grade spindle cell sarcoma of pelvic localization, BRAF exon 15 double-mutated: c.1799T>A p.V600E and c.1819T>A p.S607T in cis-position. The tumor showed resistance to CWS-based first-line chemotherapy and was treated surgically by radical resection. Seven months after surgery the patient developed metastatic relapse with abdominal carcinomatosis. Combined targeted therapy with BRAF/MEK inhibitors afforded complete response in 1 month and was continued, though complicated by severe side effects (fever, rash) necessitating 1-2 week toxicity breaks. After 4 months from commencement the disease recurred and anti-BRAF/MEK regimen consolidation was unsuccessful. Intensive salvation chemotherapy was ineffective. Empirical immunotherapy afforded a transient partial response giving way to fatal progression with massive, abdominal cocoon-complicated peritoneal carcinomatosis.

CONCLUSION

This is the first report of spindle cell sarcoma BRAF V600E/S607T double-mutated, responding to a combination of B-Raf and MEK inhibitors. Despite the low histological grade and radical surgical treatment of the tumor at primary manifestation, the disease had aggressive clinical course and the response to BRAF/MEK targeted therapy at recurrence was complete but nondurable. Empirical use of pembrolizumab provided no unambiguous evidence on the clinical relevance of immunotherapy in protein kinase -rearranged spindle cell tumors.

Patient-derived melanoma models

Melanoma is a very aggressive, rapidly metastasizing tumor that has been studied intensively in the past regarding the underlying genetic and molecular mechanisms. More recently developed treatment modalities have improved response rates and overall survival of patients. However, the majority of patients suffer from secondary treatment resistance, which requires in depth analyses of the underlying mechanisms. Here, melanoma models based on patients-derived material may play an important role. Consequently, a plethora of different experimental techniques have been developed in the past years. Among these are 3D and 4D culture techniques, organotypic skin reconstructs, melanoma-on-chip models and patient-derived xenografts, Every technique has its own strengths but also weaknesses regarding throughput, reproducibility, and reflection of the human situation. Here, we provide a comprehensive overview of currently used techniques and discuss their use in different experimental settings.

Real-world outcomes of patients with resected stage III melanoma treated with adjuvant therapies

BACKGROUND

Both immunotherapy (IO) and targeted therapy (TT) are used as adjuvant (adj) treatment for stage III melanoma, however, data describing real-world outcomes are limited. In addition, a significant proportion of patients relapse, for whom best management is unclear. The aim of our study was to assess the efficacy, and safety of adj anti-PD1 IO and TT in a real-world cohort of patients with resected stage III melanoma, and further delineate patterns of recurrence and treatment strategies.

METHODS

We retrospectively analyzed 130 patients who received adj therapy (100 anti-PD1 IO and 30 TT).

RESULTS

At a median follow-up of 30 months, median relapse-free survival (RFS) was 24.6 (95% CI, 17-not reached [NR]) versus 64 (95% CI, 29.5-NR) months for the TT and IO groups, respectively (p = 0.26). Median overall survival (OS) was NR for either subgroup. At data cutoff, 77% and 82% of patients in TT and IO arms were alive. A higher number of grade ≥3 treatment-related adverse events (AEs) were noted in the IO group (11% vs. 3%), however, a higher proportion of patients permanently discontinued adj therapy in the TT group (43% vs. 11%) due to toxicity. Strategies at relapse and outcomes were variable based on location and timing of recurrence. A significant number of patients who relapsed after adj IO received a second round of IO. Among them, patients who were off adj IO at relapse had superior second median RFS (mRFS2), compared to those who relapsed while on adj IO; mRFS2 was NR versus 5.1 months (95% CI, 2.5-NR), respectively, p = 0.02.

CONCLUSION

In summary, both TT and IO yielded prolonged RFS in a real-world setting, however, longer follow-up is needed to determine any potential OS benefit. Adj therapy, particularly TT, may not be as well tolerated as suggested in clinical trials, with lower completion rates (59% vs. 74%) in a real-life setting. Overall, patients who relapse during adj therapy have poor outcomes, while patients who relapse after discontinuation of adj IO therapy appear to benefit from IO re-treatment.

Anti-PD-(L)1 plus BRAF/MEK inhibitors (triplet therapy) after failure of immune checkpoint inhibition and targeted therapy in patients with advanced melanoma

BACKGROUND

Effective treatment options are limited for patients with advanced melanoma who have progressed on immune checkpoint inhibitors (ICI) and targeted therapies (TT). Preclinical models support the combination of ICI with TT; however, clinical trials evaluating the efficacy of triplet combinations in first-line setting showed limited advantage compared to TT only.

METHODS

We conducted a retrospective, multicenter study, that included patients with advanced melanoma who were treated with BRAF/MEK inhibitors in combination with an anti-PD-(L)1 antibody (triplet therapy) after failure of at least one anti-PD-(L)1-based therapy and one TT in seven major melanoma centers between February 2016 and July 2022.

RESULTS

A total of 48 patients were included, of which 32 patients, 66.7% had brain metastases, 37 patients (77.1%) had three or more metastatic organs and 21 patients (43.8%) had three or more treatment lines. The median follow-up time was 31.4 months (IQR, 22.27-40.45 months). The treatment with triplet therapy resulted in an ORR of 35.4% (n = 17) and a DCR of 47.9% (n = 23). The median DOR was 5.9 months (range, 3.39-14.27 months). Patients treated with BRAF/MEK inhibitors as the last treatment line showed a slightly lower ORR (29.6%) compared to patients who received ICI or chemotherapy last (ORR: 42.9%). Grade 3-4 treatment-related adverse events occurred in 25% of patients (n = 12), with seven patients (14.6%) requiring discontinuation of treatment with both or either drug.

CONCLUSIONS

Triplet therapy has shown activity in heavily pretreated patients with advanced melanoma and may represent a potential treatment regimen after failure of ICI and TT.

A multiparameter liquid biopsy approach allows to track melanoma dynamics and identify early treatment resistance

Melanoma heterogeneity is a hurdle in metastatic disease management. Although the advent of targeted therapy has significantly improved patient outcomes, the occurrence of resistance makes monitoring of the tumor genetic landscape mandatory. Liquid biopsy could represent an important biomarker for the real-time tracing of disease evolution. Thus, we aimed to correlate liquid biopsy dynamics with treatment response and progression by devising a multiplatform approach applied to longitudinal melanoma patient monitoring. We conceived an approach that exploits Next Generation Sequencing (NGS) and droplet digital PCR, as well as the FDA-cleared platform CellSearch, to analyze circulating tumor DNA (ctDNA) trend and circulating melanoma cell (CMC) count, together with their customized genetic and copy number variation analysis. The approach was applied to 17 stage IV melanoma patients treated with BRAF/MEK inhibitors, followed for up to 28 months. BRAF mutations were detected in the plasma of 82% of patients. Single nucleotide variants known or suspected to confer resistance were identified in 70% of patients. Moreover, the amount of ctDNA, both at baseline and during response, correlated with the type and duration of the response itself, and the CMC count was confirmed to be a prognostic biomarker. This work provides proof of principle of the power of this approach and paves the way for a validation study aimed at evaluating early ctDNA-guided treatment decisions in stage IV melanoma. The NGS-based molecular profile complemented the analysis of ctDNA trend and, together with CMC analysis, revealed to be useful in capturing tumor evolution.

ERK pathway agonism for cancer therapy: evidence, insights, and a target discovery framework

At least 40% of human cancers are associated with aberrant ERK pathway activity (ERKp). Inhibitors targeting various effectors within the ERKp have been developed and explored for over two decades. Conversely, a substantial body of evidence suggests that both normal human cells and, notably to a greater extent, cancer cells exhibit susceptibility to hyperactivation of ERKp. However, this vulnerability of cancer cells remains relatively unexplored. In this review, we reexamine the evidence on the selective lethality of highly elevated ERKp activity in human cancer cells of varying backgrounds. We synthesize the insights proposed for harnessing this vulnerability of ERK-associated cancers for therapeutical approaches and contextualize these insights within established pharmacological cancer-targeting models. Moreover, we compile the intriguing preclinical findings of ERK pathway agonism in diverse cancer models. Lastly, we present a conceptual framework for target discovery regarding ERKp agonism, emphasizing the utilization of mutual exclusivity among oncogenes to develop novel targeted therapies for precision oncology.

New clinical trial design in precision medicine: discovery, development and direction

In the era of precision medicine, it has been increasingly recognized that individuals with a certain disease are complex and different from each other. Due to the underestimation of the significant heterogeneity across participants in traditional "one-size-fits-all" trials, patient-centered trials that could provide optimal therapy customization to individuals with specific biomarkers were developed including the basket, umbrella, and platform trial designs under the master protocol framework. In recent years, the successive FDA approval of indications based on biomarker-guided master protocol designs has demonstrated that these new clinical trials are ushering in tremendous opportunities. Despite the rapid increase in the number of basket, umbrella, and platform trials, the current clinical and research understanding of these new trial designs, as compared with traditional trial designs, remains limited. The majority of the research focuses on methodologies, and there is a lack of in-depth insight concerning the underlying biological logic of these new clinical trial designs. Therefore, we provide this comprehensive review of the discovery and development of basket, umbrella, and platform trials and their underlying logic from the perspective of precision medicine. Meanwhile, we discuss future directions on the potential development of these new clinical design in view of the "Precision Pro", "Dynamic Precision", and "Intelligent Precision". This review would assist trial-related researchers to enhance the innovation and feasibility of clinical trial designs by expounding the underlying logic, which be essential to accelerate the progression of precision medicine.

Targeting the RAS/RAF/MAPK pathway for cancer therapy: from mechanism to clinical studies

Metastatic dissemination of solid tumors, a leading cause of cancer-related mortality, underscores the urgent need for enhanced insights into the molecular and cellular mechanisms underlying metastasis, chemoresistance, and the mechanistic backgrounds of individuals whose cancers are prone to migration. The most prevalent signaling cascade governed by multi-kinase inhibitors is the mitogen-activated protein kinase (MAPK) pathway, encompassing the RAS-RAF-MAPK kinase (MEK)-extracellular signal-related kinase (ERK) pathway. RAF kinase is a primary mediator of the MAPK pathway, responsible for the sequential activation of downstream targets, such as MEK and the transcription factor ERK, which control numerous cellular and physiological processes, including organism development, cell cycle control, cell proliferation and differentiation, cell survival, and death. Defects in this signaling cascade are associated with diseases such as cancer. RAF inhibitors (RAFi) combined with MEK blockers represent an FDA-approved therapeutic strategy for numerous RAF-mutant cancers, including melanoma, non-small cell lung carcinoma, and thyroid cancer. However, the development of therapy resistance by cancer cells remains an important barrier. Autophagy, an intracellular lysosome-dependent catabolic recycling process, plays a critical role in the development of RAFi resistance in cancer. Thus, targeting RAF and autophagy could be novel treatment strategies for RAF-mutant cancers. In this review, we delve deeper into the mechanistic insights surrounding RAF kinase signaling in tumorigenesis and RAFi-resistance. Furthermore, we explore and discuss the ongoing development of next-generation RAF inhibitors with enhanced therapeutic profiles. Additionally, this review sheds light on the functional interplay between RAF-targeted therapies and autophagy in cancer.

Decisions about treatment with targeted therapies in a palliative care unit: A case series

BACKGROUND

Early palliative care integration into the oncologic treatment pattern is recognized and strongly recommended to anticipate end-of-life issues and avoid disproportionate care. Targeted therapies (TTs), with their very rapid onset of action and relatively good tolerance, may have an effect on cancer-related symptoms, which could be beneficial in the context of palliative care.

METHODS

Data were extracted from a cohort of all patients hospitalized in an acute palliative care unit between 03.04.2019 and 07.04.2020. Data for all consecutive patients for which a decision on a TT was made during hospitalization were retrospectively analyzed.

RESULTS

Forty-two patients were identified. Thirty-one patients were currently receiving TT on admission. For 19/31 (61.3%) patients, the treatment was discontinued. The remaining 12 patients had TT after discharge from the palliative care unit (continuation of the same TT or modification of the TT during the stay), with an average duration of 208 days and an average of 46 days between the last TT and death. TT was introduced or reintroduced in 7 patients of the 11 patients hospitalized without treatment at admission. In this group, the average duration of treatment was 28 days, with an average of 28 days between the last TT and death. Five of the patients who received re-challenged TT experienced a subjective improvement of their symptom.

SIGNIFICANCE OF RESULTS

TT was discontinued in the majority of our patients. However, in some cases, the treatment was maintained because it was effective on cancer-related symptoms even at the end of life. However, this should not overshadow the palliative process. The continuation or introduction of a specific oncological treatment requires close cooperation between oncologists and palliative care physicians and an honest and clear explanation to patients and their families.

H3K4me3 remodeling induced acquired resistance through O-GlcNAc transferase

AIMS

Drivers of the drug tolerant proliferative persister (DTPP) state have not been well investigated. Histone H3 lysine-4 trimethylation (H3K4me3), an active histone mark, might enable slow cycling drug tolerant persisters (DTP) to regain proliferative capacity. This study aimed to determine H3K4me3 transcriptionally active sites identifying a key regulator of DTPPs.

METHODS

Deploying a model of adaptive cancer drug tolerance, H3K4me3 ChIP-Seq data of DTPPs guided identification of top transcription factor binding motifs. These suggested involvement of O-linked N-acetylglucosamine transferase (OGT), which was confirmed by metabolomics analysis and biochemical assays. OGT impact on DTPPs and adaptive resistance was explored in vitro and in vivo.

RESULTS

H3K4me3 remodeling was widespread in CPG island regions and DNA binding motifs associated with O-GlcNAc marked chromatin. Accordingly, we observed an upregulation of OGT, O-GlcNAc and its binding partner TET1 in chronically treated cancer cells. Inhibition of OGT led to loss of H3K4me3 and downregulation of genes contributing to drug resistance. Genetic ablation of OGT prevented acquired drug resistance in in vivo models. Upstream of OGT, we identified AMPK as an actionable target. AMPK activation by acetyl salicylic acid downregulated OGT with similar effects on delaying acquired resistance.

CONCLUSION

Our findings uncover a fundamental mechanism of adaptive drug resistance that governs cancer cell reprogramming towards acquired drug resistance, a process that can be exploited to improve response duration and patient outcomes.

Treatment management for BRAF-mutant melanoma patients with tumor recurrence on adjuvant therapy: a multicenter study from the prospective skin cancer registry ADOREG

BACKGROUND

Adjuvant therapy with immune-checkpoint inhibitors (CPI) or BRAF/MEK-directed targeted therapy (TT) improves recurrence-free survival (RFS) for patients with advanced, BRAFV600-mutant (BRAFmut) resected melanoma. However, 40% of these patients will develop distant metastases (DM) within 5 years, which require systemic therapy. Little data exist to guide the choice of upfront adjuvant therapy or treatment management upon DM. This study evaluated the efficacy of subsequent treatments following tumor recurrence upon upfront adjuvant therapy.

METHODS

For this multicenter cohort study, we identified 515 BRAFmut patients with resected stage III melanoma who were treated with PD-1 inhibitors (anti-PD1) or TT in the adjuvant setting. Disease characteristics, treatment regimens, details on tumor recurrence, subsequent treatment management, and survival outcomes were collected within the prospective, real-world skin cancer registry ADOReg. Primary endpoints included progression-free survival (PFS) following DM and best tumor response to first-line (1L) treatments.

RESULTS

Among 515 eligible patients, 273 patients received adjuvant anti-PD1 and 242 adjuvant TT. At a median follow-up of 21 months, 54.6% of anti-PD1 patients and 36.4% of TT patients recurred, while 39.6% (anti-PD1) and 29.3% (TT) developed DM. Risk of recurrence was significantly reduced in patients treated with TT compared with anti-PD1 (adjusted HR 0.52; 95% CI 0.40 to 0.68, p<0.001). Likewise, median RFS was significantly longer in TT-treated patients (31 vs 17 months, p<0.001). Patients who received TT as second adjuvant treatment upon locoregional recurrence had a longer RFS2 as compared with adjuvant CPI (41 vs 6 months, p=0.009). Patients who recurred at distant sites following adjuvant TT showed favorable response rates (42.9%) after switching to 1L ipilimumab+nivolumab (ipi+nivo). Patients with DM during adjuvant anti-PD1 achieved response rates of 58.7% after switching to 1L TT and 35.3% for 1L ipi+nivo. Overall, median PFS was significantly longer in patients who switched treatments for stage IV disease (median PFS 9 vs 5 months, p=0.004).

CONCLUSIONS

BRAFmut melanoma patients who developed DM upon upfront adjuvant therapy achieve favorable tumor control and prolonged PFS after switching treatment modalities in the first-line setting of stage IV disease. Patients with locoregional recurrence benefit from complete resection of recurrence followed by a second adjuvant treatment with TT.

Efficacy and Safety of Rechallenge with BRAF/MEK Inhibitors in Advanced Melanoma Patients: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis aims to evaluate the efficacy and safety of rechallenging advanced melanoma patients with BRAFi/MEKi. Seven studies, accounting for 400 patients, were included. Most patients received immunotherapy before the rechallenge, and 79% underwent rechallenge with the combination of BRAFi/MEKi. We found a median progression-free survival of 5 months and overall survival of 9.8 months. The one-year survival rate was 42.63%. Regarding response, ORR was 34% and DCR 65%. There were no new or unexpected safety concerns. Rechallenge with BRAFi/MEKi can improve outcomes in advanced melanoma patients with refractory disease. These findings have significant implications for clinical practice, particularly in the setting of progressive disease in later lines and limited treatment options.

Melanoma: BRAFi Rechallenge

Melanoma is the most aggressive type of skin cancer. Half of melanoma cases are characterized by the mutation BRAF V600. The case presented concerns a 41-year-old patient with locally advanced melanoma, being positive in mutation BRAF V600. The patient underwent surgery and received additional targeted therapy as part of a clinical study. In subsequent disease progression, immunotherapy was used. When the disease progressed again while the patient was in a good performance status, targeted therapy was administered again, and a good response was noted, making the patient reach a statistically significant overall survival, exceeding four years. Targeted therapy has proven to be an important tool in the treatment of melanoma. The use of BRAFi targeted therapy does not exclude the option of readministration at subsequent disease progression (BRAFi rechallenge). Preclinical models suggest that the resistance mechanism of cancer cells to BRAFi therapy bends, as these cell clones lose their evolutionary advantage after stopping BRAFi. Cell clones sensitive to BRAFi may then outcompete, making the treatment effective again. Therapeutical dilemmas in the management of patients with locally advanced melanoma that progresses to metastatic cancer are discussed.

Trametinib-Resistant Melanoma Cells Displaying MITFhigh/NGFRlow/IL-8low Phenotype Are Highly Responsive to Alternating Periods of Drug Withdrawal and Drug Rechallenge

Despite significant advances in targeted therapies against the hyperactivated BRAF^V600/MEK pathway for patients with unresectable metastatic melanoma, acquired resistance remains an unsolved clinical problem. In this study, we focused on melanoma cells resistant to trametinib, an agent broadly used in combination therapies. Molecular and cellular changes were assessed during alternating periods of trametinib withdrawal and rechallenge in trametinib-resistant cell lines displaying either a differentiation phenotype (MITF^high/NGFR^low) or neural crest stem-like dedifferentiation phenotype (NGFR^high/MITF^low). Neither drug withdrawal nor drug rechallenge induced cell death, and instead of loss of fitness, trametinib-resistant melanoma cells adapted to altered conditions by phenotype switching. In resistant cells displaying a differentiation phenotype, trametinib withdrawal markedly decreased MITF level and activity, which was associated with reduced cell proliferation capacity, and induced stemness assessed as NGFR-positive cells and senescence features, including IL-8 expression and secretion. All these changes could be reversed by trametinib re-exposure, which emphasizes melanoma cell plasticity. Trametinib-resistant cells displaying a dedifferentiation phenotype were less responsive presumably due to the already low level of MITF, a master regulator of the melanoma phenotype. Considering new directions of the development of anti-melanoma treatment, our study suggests that the phenotype of melanomas resistant to targeted therapy might be a crucial determinant of the selection of second-line therapy for melanoma patients.

Tolerability of BRAF and MEK Inhibitors for Metastasized Melanoma after Intra-Class Switch: A Multicenter, Retrospective Study

Targeted therapy with BRAF and MEK inhibitors (BRAFi, MEKi) is one of the mainstays of melanoma treatment. When dose-limiting toxicity (DLT) is observed, an option represents the intra-class switch to a different BRAFi+MEKi combination. Currently, there is scarce evidence for this procedure. This is a multicenter, retrospective analysis from six German skin cancer centers of patients who received two different combinations of BRAFi and MEKi. In total, 94 patients were included: 38 patients (40%) were re-exposed with a different combination because of previous unacceptable toxicity, 51 (54%) were re-exposed after progression, and 5 (5%) were included for other reasons. Of the 44 patients with a DLT during their first BRAFi+MEKi combination, only five (11%) experienced the same DLT during their second combination. A new DLT was experienced by 13 patients (30%). Six patients (14%) had to discontinue the second BRAFi treatment due to its toxicity. Compound-specific adverse events were avoided in the majority of patients by switching to a different combination. Efficacy data were similar to historical cohorts of BRAFi+MEKi rechallenge, with an overall response rate of 31% for patients who had previously progressed to treatment. We conclude that switching to a different BRAFi+MEKi combination if dose-limiting toxicity occurs is a feasible and rational approach in patients with metastatic melanoma.

BRAF v600E-mutant cancers treated with vemurafenib alone or in combination with everolimus, sorafenib, or crizotinib or with paclitaxel and carboplatin (VEM-PLUS) study

Combined BRAF + MEK inhibition is FDA approved for BRAF V600E-mutant solid tumors except for colorectal cancer. However, beyond MAPK mediated resistance several other mechanisms of resistance such as activation of CRAF, ARAF, MET, P13K/AKT/mTOR pathway exist among other complex pathways. In the VEM-PLUS study, we performed a pooled analysis of four phase one studies evaluating the safety and efficacy of vemurafenib monotherapy and vemurafenib combined with targeted therapies (sorafenib, crizotinib, or everolimus) or carboplatin plus paclitaxel in advanced solid tumors harboring BRAF V600 mutations. When vemurafenib monotherapy was compared with the combination regimens, no significant differences in OS or PFS durations were noted, except for inferior OS in the vemurafenib and paclitaxel and carboplatin trial (P = 0.011; HR, 2.4; 95% CI, 1.22-4.7) and in crossover patients (P = 0.0025; HR, 2.089; 95% CI, 1.2-3.4). Patients naïve to prior BRAF inhibitors had statistically significantly improved OS at 12.6 months compared to 10.4 months in the BRAF therapy refractory group (P = 0.024; HR, 1.69; 95% CI 1.07-2.68). The median PFS was statistically significant between both groups, with 7 months in the BRAF therapy naïve group compared to 4.7 months in the BRAF therapy refractory group (P = 0.016; HR, 1.80; 95% CI 1.11-2.91). The confirmed ORR in the vemurafenib monotherapy trial (28%) was higher than that in the combination trials. Our findings suggest that, compared with vemurafenib monotherapy, combinations of vemurafenib with cytotoxic chemotherapy or with RAF- or mTOR-targeting agents do not significantly extend the OS or PFS of patients who have solid tumors with BRAF V600E mutations. Gaining a better understanding of the molecular mechanisms of BRAF inhibitor resistance, balancing toxicity and efficacy with novel trial designs are warranted.

BRAF and MEK Inhibitors and Their Toxicities: A Meta-Analysis

PURPOSE

This meta-analysis summarizes the incidence of treatment-related adverse events (AE) of BRAFi and MEKi.

METHODS

A systematic search of Medline/PubMed was conducted to identify suitable articles published in English up to 31 December 2021. The primary outcomes were profiles for all-grade and grade 3 or higher treatment-related AEs, and the analysis of single side effects belonging to both categories.

RESULTS

The overall incidence of treatment-related all-grade Aes was 99% for Encorafenib (95% CI: 0.97-1.00) and 97% for Trametinib (95% CI: 0.92-0.99; I² = 66%) and Binimetinib (95% CI: 0.94-0.99; I² = 0%). In combined therapies, the rate was 98% for both Vemurafenib + Cobimetinib (95% CI: 0.96-0.99; I² = 77%) and Encorafenib + Binimetinib (95% CI: 0.96-1.00). Grade 3 or higher adverse events were reported in 69% of cases for Binimetinib (95% CI: 0.50-0.84; I² = 71%), 68% for Encorafenib (95% CI: 0.61-0.74), and 72% for Vemurafenib + Cobimetinib (95% CI: 0.65-0.79; I² = 84%). The most common grade 1-2 AEs were pyrexia (43%) and fatigue (28%) for Dabrafenib + Trametinib and diarrhea for both Vemurafenib + Cobimetinib (52%) and Encorafenib + Binimetinib (34%). The most common AEs of grade 3 or higher were pyrexia, rash, and hypertension for Dabrafenib + Trametinib (6%), rash and hypertension for Encorafenib + Binimetinib (6%), and increased AST and ALT for Vemurafenib + Cobimetinib (10%).

CONCLUSIONS

Our study provides comprehensive data on treatment-related adverse events of BRAFi and MEKi combination therapies, showing related toxicity profiles to offer a helpful tool for clinicians in the choice of therapy.

Treatment Approaches for Melanomas That Relapse After Adjuvant or Neoadjuvant Therapy

PURPOSE OF REVIEW

Effective adjuvant treatment with immunotherapy and targeted therapy has significantly improved outcomes for patients with resectable locally advanced or metastatic melanoma, but a substantial proportion unfortunately relapse. Here, we review available data and explore evolving research which might impact decision-making in this setting.

RECENT FINDINGS

Small retrospective studies have explored pattern of disease relapse and observed outcomes of subsequent treatment. There are ongoing trials in the neoadjuvant setting which may provide valuable information regarding disease response and potentially change the way we approach disease relapse. Currently there is limited evidence to guide clinicians in managing melanomas that relapse after adjuvant therapy. Standardised data collection and future prospective studies are needed.

Perspectives in Melanoma: meeting report from the Melanoma Bridge (December 2nd - 4th, 2021, Italy)

Advances in immune checkpoint and combination therapy have led to improvement in overall survival for patients with advanced melanoma. Improved understanding of the tumor, tumor microenvironment and tumor immune-evasion mechanisms has resulted in new approaches to targeting and harnessing the host immune response. Combination modalities with other immunotherapy agents, chemotherapy, radiotherapy, electrochemotherapy are also being explored to overcome resistance and to potentiate the immune response. In addition, novel approaches such as adoptive cell therapy, oncogenic viruses, vaccines and different strategies of drug administration including sequential, or combination treatment are being tested. Despite the progress in diagnosis of melanocytic lesions, correct classification of patients, selection of appropriate adjuvant and systemic theràapies, and prediction of response to therapy remain real challenges in melanoma. Improved understanding of the tumor microenvironment, tumor immunity and response to therapy has prompted extensive translational and clinical research in melanoma. There is a growing evidence that genomic and immune features of pre-treatment tumor biopsies may correlate with response in patients with melanoma and other cancers, but they have yet to be fully characterized and implemented clinically. Development of novel biomarker platforms may help to improve diagnostics and predictive accuracy for selection of patients for specific treatment. Overall, the future research efforts in melanoma therapeutics and translational research should focus on several aspects including: (a) developing robust biomarkers to predict efficacy of therapeutic modalities to guide clinical decision-making and optimize treatment regimens, (b) identifying mechanisms of therapeutic resistance to immune checkpoint inhibitors that are potentially actionable, (c) identifying biomarkers to predict therapy-induced adverse events, and (d) studying mechanism of actions of therapeutic agents and developing algorithms to optimize combination treatments. During the Melanoma Bridge meeting (December 2nd-4th, 2021, Naples, Italy) discussions focused on the currently approved systemic and local therapies for advanced melanoma and discussed novel biomarker strategies and advances in precision medicine as well as the impact of COVID-19 pandemic on management of melanoma patients.

Using targeted therapies at the end of life

The prescription of chemotherapy during the last weeks of a patient’s life is a recognised criterion of decreasing quality of life but also survival. Targeted therapies have a particular efficiency and tolerance profile raising the question of their use in a palliative setting. Two patients were treated for a melanoma, at terminal stage, with poor efficiency of the symptomatic treatments. We introduced targeted therapies, which was previous treatments used in both patients.The evolution and benefits of the treatment was very different in our two patients and make us discuss the interest of targeted therapies in an end-of-life context and propose criteria for their maintenance or introduction in this indication. This discussion requires close collaboration between oncologists and palliative physicians and a very clear information given to patients and their relatives.

A lead-in safety study followed by a phase 2 clinical trial of dabrafenib, trametinib and hydroxychloroquine in advanced BRAFV600 mutant melanoma patients previously treated with BRAF-/MEK-inhibitors and immune checkpoint inhibitors

Patients with advanced BRAFV600 mutant melanoma who progressed on prior treatment with BRAF-/MEK-inhibitors and programmed cell death 1 or cytotoxic T-lymphocyte-associated antigen 4 immune checkpoint inhibitors can benefit from retreatment with the combination of a BRAF- and a MEK-inhibitor ('rechallenge'). Hydroxychloroquine can prevent autophagy-driven resistance and improve the efficacy of BRAF-/MEK-inhibitors in preclinical melanoma models. This clinical trial investigated the use of combined BRAF-/MEK-inhibition with dabrafenib and trametinib plus hydroxychloroquine in patients with advanced BRAFV600 mutant melanoma who previously progressed on prior treatment with BRAF-/MEK-inhibitors and immune checkpoint inhibitors. Following a safety lead-in phase, patients were randomized in the phase 2 part of the trial between upfront treatment with dabrafenib, trametinib and hydroxychloroquine (experimental arm), or dabrafenib and trametinib, with the possibility to add-on hydroxychloroquine at the time of documented tumor progression (contemporary control arm). Ten and four patients were recruited to the experimental and contemporary control arm, respectively. The objective response rate was 20.0% and the disease control rate was 50.0% in the experimental arm, whereas no responses were observed before or after adding hydroxychloroquine in the contemporary control arm. No new safety signals were observed for dabrafenib and trametinib. Hydroxychloroquine was suspected of causing an anxiety/psychotic disorder in one patient. Based on an early negative evaluation of the risk/benefit ratio for adding hydroxychloroquine to dabrafenib and trametinib when 'rechallenging' BRAFV600mutant melanoma patients, recruitment to the trial was closed prematurely.

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.

Intermittent treatment of BRAFV600E melanoma cells delays resistance by adaptive resensitization to drug rechallenge

Preclinical studies of metastatic melanoma treated with targeted therapeutics have suggested that alternating periods of treatment and withdrawal might delay the onset of resistance. This has been attributed to drug addiction, where cells lose fitness upon drug removal due to the resulting hyperactivation of mitogen-activated protein (MAP) kinase signaling. This study presents evidence that the intermittent treatment response can also be explained by the resensitization of cells following drug removal and enhanced cell loss upon drug rechallenge. Resensitization is accompanied by adaptive transcriptomic switching and occurs despite the sustained expression of resistance genes throughout the intermittent treatment.

Patients with melanoma receiving drugs targeting BRAF^V600E and mitogen-activated protein (MAP) kinase kinases 1 and 2 (MEK1/2) invariably develop resistance and face continued progression. Based on preclinical studies, intermittent treatment involving alternating periods of drug withdrawal and rechallenge has been proposed as a method to delay the onset of resistance. The beneficial effect of intermittent treatment has been attributed to drug addiction, where drug withdrawal reduces the viability of resistant cells due to MAP kinase pathway hyperactivation. However, the mechanistic basis of the intermittent effect is incompletely understood. We show that intermittent treatment with the BRAF^V600E inhibitor, LGX818/encorafenib, suppresses growth compared with continuous treatment in human melanoma cells engineered to express BRAF^V600E, p61-BRAF^V600E, or MEK2^C125 oncogenes. Analysis of the BRAF^V600E-overexpressing cells shows that, while drug addiction clearly occurs, it fails to account for the advantageous effect of intermittent treatment. Instead, growth suppression is best explained by resensitization during periods of drug removal, followed by cell death after drug readdition. Continuous treatment leads to transcriptional responses prominently associated with chemoresistance in melanoma. By contrast, cells treated intermittently reveal a subset of transcripts that reverse expression between successive cycles of drug removal and rechallenge and include mediators of cell invasiveness and the epithelial-to-mesenchymal transition. These transcripts change during periods of drug removal by adaptive switching, rather than selection pressure. Resensitization occurs against a background of sustained expression of melanoma resistance genes, producing a transcriptome distinct from that of the initial drug-naive cell state. We conclude that phenotypic plasticity leading to drug resensitization can underlie the beneficial effect of intermittent treatment.

Pancreatic Neuroendocrine Neoplasms: Updates on Genomic Changes in Inherited Tumour Syndromes and Sporadic Tumours Based on WHO Classification

Pancreatic neuroendocrine neoplasms (PanNENs) are the neuroendocrine neoplasms with greatest rate of increase in incidence. Approximately 10% of PanNENs arise as inherited tumour syndromes which include multiple endocrine neoplasia type 1, multiple endocrine neoplasia type 4, von Hippel-Lindau syndrome, neurofibromatosis type1, tuberous sclerosis complex 1/2, Cowden syndrome, and Glucagon cell hyperplasia and neoplasia as well as familial insulinomatosis. In sporadic PanNENs, driver mutations in MEN1, DAXX/ATRX and mTOR pathway genes are associated with development and progression in pancreatic neuroendocrine tumours. The other changes are in VEGF pathway, Notch pathway, germline mutations in MUTYH, CHEK2, BRCA2, PHLDA3 as well as other genetic alterations. On the other hand, pancreatic neuroendocrine carcinomas share similar genetic alterations with ductal adenocarcinomas, e.g., TP53, RB1 or KRAS. In addition, microRNA and changes in immune microenvironment were noted in PanNENs. Updates on these genetic knowledges contribute to the development of management strategies for patients with PanNENs.

Corticosteroid-Refractory Myositis After Dual BRAF and MEK Inhibition in a Patient with BRAF V600E-Mutant Metastatic Intrahepatic Cholangiocarcinoma

Intrahepatic cholangiocarcinoma is a rare malignancy, which is rich in actionable alterations. Genomic aberrations in the mitogen-activated protein kinase (MAPK) pathway are common, and BRAF exon 15 p.V600E mutations are present in 5–7% of biliary tract cancers (BTC). Dual inhibition of BRAF and MEK has been established for BRAF-mutated melanoma and lung cancer, and recent basket trials have shown efficacy of this combination in BRAF V600E-mutant BTCs. Here, we report on a patient with BRAF exon 15 p.V600E mutant metastatic intrahepatic cholangiocarcinoma who was started on BRAF and MEK inhibition with vemurafenib and combimetinib. Shortly thereafter, he developed debilitating myositis, which was refractory to corticosteroids, requiring therapeutic plasma exchange and intravenous immunoglobulin. We also review BRAF as a target in BTCs, relevant clinical trials, and adverse events associated with BRAF and MEK inhibition.

Proteomic Changes in the Monolayer and Spheroid Melanoma Cell Models of Acquired Resistance to BRAF and MEK1/2 Inhibitors

Extracellular signal-regulated kinase-1/2 (ERK1/2) pathway inhibitors are important therapies for treating many cancers. However, acquired resistance to most protein kinase inhibitors limits their ability to provide durable responses. Approximately 50% of malignant melanomas contain activating mutations in BRAF, which promotes cancer cell survival through the direct phosphorylation of the mitogen-activated protein kinase MAPK/ERK 1/2 (MEK1/2) and the activation of ERK1/2. Although the combination treatment with BRAF and MEK1/2 inhibitors is a recommended approach to treat melanoma, the development of drug resistance remains a barrier to achieving long-term patient benefits. Few studies have compared the global proteomic changes in BRAF/MEK1/2 inhibitor-resistant melanoma cells under different growth conditions. The current study uses high-resolution label-free mass spectrometry to compare relative protein changes in BRAF/MEK1/2 inhibitor-resistant A375 melanoma cells grown as monolayers or spheroids. While approximately 66% of proteins identified were common in the monolayer and spheroid cultures, only 6.2 or 3.6% of proteins that significantly increased or decreased, respectively, were common between the drug-resistant monolayer and spheroid cells. Drug-resistant monolayers showed upregulation of ERK-independent signaling pathways, whereas drug-resistant spheroids showed primarily elevated catabolic metabolism to support oxidative phosphorylation. These studies highlight the similarities and differences between monolayer and spheroid cell models in identifying actionable targets to overcome drug resistance.

CircNFIB inhibits tumor growth and metastasis through suppressing MEK1/ERK signaling in intrahepatic cholangiocarcinoma

BACKGROUND

Considerable evidence shows that circular RNAs (circRNAs) play an important role in tumor development. However, their function in intrahepatic cholangiocarcinoma (ICC) metastasis and the underlying mechanisms are incompletely understood.

METHODS

circNFIB (hsa_circ_0086376, termed as cNFIB hereafter) was identified in human ICC tissues through circRNAs sequencing. The biological role of cNFIB was determined in vitro and in vivo by gain or loss of functional experiments. Fluorescence in situ hybridization (FISH), RNA immunoprecipitation (RIP) and RNA pull-down assays were conducted to analyze the interaction of cNFIB with dual specificity mitogen-activated protein kinase kinase1 (MEK1). Duolink in situ proximity ligation assay (PLA) and coimmunoprecipitation (co-IP) assay were used to investigate the effects of cNFIB on the interaction between MEK1 and mitogen-activated protein kinase 2 (ERK2). Finally, a series of in vitro and in vivo experiments were performed to explore the influences of cNFIB on the anti-tumor activity of trametinib (a MEK inhibitor).

RESULTS

cNFIB was significantly down-regulated in human ICC tissues with postoperative metastases. The loss of cNFIB was highly associated with aggressive characteristics and predicted unfavorable prognosis in ICC patients. Functional studies revealed that cNFIB inhibited the proliferation and metastasis of ICC cells in vitro and in vivo. Mechanistically, cNFIB competitively interacted with MEK1, which induced the dissociation between MEK1 and ERK2, thereby resulting in the suppression of ERK signaling and tumor metastasis. Moreover, we found that ICC cells with high levels of cNFIB held the potential to delay the trametinib resistance. Consistently, in vivo and in vitro studies demonstrated that cotreatment with trametinib and lentivirus vector encoding cNFIB showed greater inhibitory effect than isolated trametinib treatment.

CONCLUSIONS

Our findings identified that cNFIB played a key role in ICC growth and metastasis by regulating MEK1/ERK signaling. Given the efficacy of cNFIB modulation on ICC suppression and trametinib sensitivity, cNFIB appears to be a potential therapeutic molecule for ICC treatment.

Identification of a novel tumour microenvironment-based prognostic biomarker in skin cutaneous melanoma

Skin cutaneous melanoma (SKCM) is one of the most destructive skin malignancies and has attracted worldwide attention. However, there is a lack of prognostic biomarkers, especially tumour microenvironment (TME)-based prognostic biomarkers. Therefore, there is an urgent need to investigate the TME in SKCM, as well as to identify efficient biomarkers for the diagnosis and treatment of SKCM patients. A comprehensive analysis was performed using SKCM samples from The Cancer Genome Atlas and normal samples from Genotype-Tissue Expression. TME scores were calculated using the ESTIMATE algorithm, and differential TME scores and differentially expressed prognostic genes were successively identified. We further identified more reliable prognostic genes via least absolute shrinkage and selection operator regression analysis and constructed a prognostic prediction model to predict overall survival. Receiver operating characteristic analysis was used to evaluate the diagnostic efficacy, and Cox regression analysis was applied to explore the relationship with clinicopathological characteristics. Finally, we identified a novel prognostic biomarker and conducted a functional enrichment analysis. After considering ESTIMATEScore and tumour purity as differential TME scores, we identified 34 differentially expressed prognostic genes. Using least absolute shrinkage and selection operator regression, we identified seven potential prognostic biomarkers (SLC13A5, RBM24, IGHV3OR16-15, PRSS35, SLC7A10, IGHV1-69D and IGHV2-26). Combined with receiver operating characteristic and regression analyses, we determined PRSS35 as a novel TME-based prognostic biomarker in SKCM, and functional analysis enriched immune-related cells, functions and signalling pathways. Our study indicated that PRSS35 could act as a potential prognostic biomarker in SKCM by investigating the TME, so as to provide new ideas and insights for the clinical diagnosis and treatment of SKCM.

Adjuvant Therapy for Cutaneous Melanoma

This article presents the current data supporting adjuvant therapy for patients with cutaneous melanoma. With the recent development of novel immunotherapy agents as well as targeted therapy, there are strong data to support the use of these therapies in patients at high risk of developing recurrent or metastatic disease.

Mitogen-activated protein kinase blockade in melanoma: intermittent versus continuous therapy, from preclinical to clinical data

PURPOSE OF REVIEW

Although targeted therapy provides a high response rate and rapid disease control in advanced melanoma, most patients experience disease progression due to acquired resistance mechanisms leading to reactivation of mitogen-activated protein kinase pathway. The purpose of this article is to review the recently published data on the impact of an intermittent versus continuous dosing schedule of BRAF and MEK inhibition in advanced melanoma to determine the best approach in clinical practice.

RECENT FINDINGS

Some preclinical studies have highlighted the concept that drug-resistant cells may also display drug dependency, such that intermittent dosing of targeted therapy may prevent the emergence of lethal drug resistance. Moreover, clinical observations have suggested that repeated treatment after a break or an intervening therapy may provide clinical benefit. However, recent preclinical and clinical studies have also failed to demonstrate an advantage of intermittent dosing and showed a similar efficacy of the intermittent versus continuous regimens of BRAF and MEK inhibitors in mice models and phase 2 clinical trial.

SUMMARY

Owing to these discordant results, continuous dosing of BRAF and MEK inhibitors remains the optimal therapeutic approach until additional clinical data demonstrate the superiority of another combination or dosing regimen.

BRAF and MEK inhibitors rechallenge as effective treatment for patients with metastatic melanoma

Despite considerable progress made in the treatment of patients with advanced melanoma, the majority of the patients treated with BRAF and mitogen-activated protein inhibitors (BRAFi and MEKi) experience a disease progression due to acquired resistance. Currently, ongoing studies explore the possibility to overcome or reverse this process. Our multicenter retrospective analysis included 51 patients with metastatic BRAF-mutated melanoma who had previously progressed on BRAFi/MEKi than had progressed on immunotherapy (anti-progression disease-1 or anti-cytotoxic T-lymphocyte-associated protein 4) and next were rechallenged with BRAFi/MEKi. Median age at BRAFi/MEKi rechallenge was 56 (range: 31-82 y/o). Median overall survival from the start of the first BRAFi/MEKi therapy and from rechallenge BRAFi/MEKi treatment was 29.7 and 9.3 months, respectively, whereas median progression-free survival was 10.5 and 5.9 months, respectively. Six-month, annual, and 2-year overall survival rates on both treatments were: 98% and 55%, 92% and 29%, and 69% and 2%, respectively. A response rate to treatment was higher in the group receiving BRAFi/MEKi for the first time as compared with the group receiving BRAFi/MEKi rechallenge and was overall response rate 72% and 27%; disease control rate 92% and 63%. Time interval between the end of the first BRAFi/MEKi treatment and the beginning of BRAFi/MEKi rechallenge did not influence median overall survival or progression-free survival. A lower toxicity rate was noted with BRAFi/MEKi rechallenge. BRAFi/MEKi rechallenge treatment remains clinically important and is associated with the lower toxicity. BRAFi/MEKi rechallenge efficacy is higher in patients who are in good performance status, with normal lactate dehydrogenase, and without brain metastases.

Characterization and Clinical Utility of BRAFV600 Mutation Detection Using Cell-Free DNA in Patients with Advanced Melanoma

Simple Summary

The choice of cancer drug(s) for the treatment of advanced melanoma is based on the types of gene alterations that are present in the patient’s tumor(s). Sometimes, the tumor sample that is obtained from surgery may be degraded, and the test does not provide a reliable result, leading to the selection of the wrong treatment, and, consequently, poor outcomes for the patient. Surgery to obtain fresh tumor samples is inconvenient. In recent years, scientists have learned that fragments of genes from dying cells, including tumors, are constantly being released into the blood. This study shows that the presence of altered genes can be reliably determined using easy-to-obtain blood samples. The study also shows that, while there is a small rate of error with the commonly used tests based on the tumor tissue sample, retests using blood samples may be a less invasive and rapid alternative for identifying the BRAF mutation status and selecting the right treatment for these patients.

Abstract

Tissue-based tests for BRAF^V600 mutation-positive melanoma involve invasive biopsy procedures, and can lead to an erroneous diagnosis when the tumor samples degrade. Herein, we explored a minimally invasive, cell-free deoxyribonucleic acid (cfDNA)-based platform, to retest patients for BRAF^V600 mutations. This phase 2 study enrolled adult patients with unresectable/metastatic melanoma. A prescreening testing phase evaluated the concordance between a prior tissue-based BRAF^V600 mutation test result and a subsequent plasma cfDNA-based test result. A treatment phase evaluated the patients who were confirmed as BRAF^V600 mutation-positive, and were treated with cobimetinib plus vemurafenib. It was found that 35/54 patients (64.8%) with a mutant BRAF status by prior tissue test had a positive BRAF^V600 mutation with the cfDNA test. Further, 7/118 patients (5.9%) with a wild-type BRAF status had a positive BRAF^V600 mutation cfDNA test; tissue retests on archival samples confirmed BRAF^V600 mutation positivity in 5/7 patients (71.4%). One of these patients received BRAF pathway-targeted therapy (cobimetinib plus vemurafenib), and had progression-free survival commensurate with previous experience. In the overall cobimetinib plus vemurafenib-treated population, 29/36 patients (80.6%) had an objective response. The median progression-free survival was 13.6 months (95% confidence interval, 9.5–16.5). Cell-free DNA–based tests may be a fast and convenient option to identify BRAF mutation status in melanoma patients, and help inform treatment decisions.

Outcomes after retreatment with MAPK inhibitors and immune checkpoint inhibitors in melanoma patients

Background: When patients with advanced melanoma progress after MAPK inhibitor (MAPKI) and immune checkpoint inhibitor (ICI) treatment, they can either undergo chemotherapy or rechallenge with previously used treatments. Methods: The outcomes of 48 patients retreated with MAPKIs and 50 patients retreated with ICIs following progression were retrospectively analyzed. Results: Upon retreatment with MAPKIs, the disease control rate was 60%. Univariate analysis of possible risk factors associated with short progression-free survival upon MAPKI treatment showed elevated lactate dehydrogenase to be associated with decreased progression-free survival. Disease control rate after ICI retreatment was 24%. Melanoma of unknown primary was associated with prolonged progression-free survival upon ICI retreatment. Conclusion: Retreatment with MAPKIs or ICIs is a feasible option for patients with advanced melanoma.

The incidence and risk of cutaneous toxicities associated with dabrafenib in melanoma patients: a systematic review and meta-analysis

OBJECTIVE

Dabrafenib, an inhibitor of mutated BRAF, has significant clinical activity in melanoma patients but is linked to a spectrum of cutaneous toxicities. Thus, our meta-analysis was conducted to evaluate the type, incidence and risks of dermatological toxicities from dabrafenib.

METHODS

Systematic searches were performed using electronic databases such as Embase and PubMed and conference abstracts published by the American Society of Clinical Oncology. Eligible studies were limited to prospective phase I, II and III clinical trials and expanded-access (ie, outside clinical trials) programmes of melanoma patients receiving dabrafenib monotherapy (150 mg, twice daily) or combination therapy of dabrafenib (150 mg, twice daily) plus trametinib (2 mg, once daily). The outcomes were mainly the incidence rate and risk of all-grade cutaneous toxicities associated with dabrafenib in melanoma patients.

RESULTS

Twenty trials comprising a total of 3359 patients were included in the meta-analysis. The meta-analysis showed that the overall incidence of all-grade rash for melanoma patients assigned dabrafenib was 30.00% (95% CI 0.07 to 0.71), cutaneous squamous-cell carcinoma (cSCC) 16.00% (95% CI 0.11 to 0.24), alopecia 21% (95% CI 0.11 to 0.37), keratoacanthoma (KA) 20.00% (95% CI 0.12 to 0.31), hyperkeratosis (HK) 14.00% (95% CI 0.09 to 0.22) and pruritus 8.00% (95% CI 0.05 to 0.12). All-grade rash occurred in 19.00% (95% CI 0.15 to 0.25), cSCC in 10.00% (95% CI 0.04 to 0.22), alopecia in 6.00% (95% CI 0.03 to 0.12), KA in 6.00% (95% CI 0.04 to 0.09) and pruritus in 2/1265 patients assigned dabrafenib plus trametinib. The summary risk ratio (RR) showed that the combination of dabrafenib with trametinib versus dabrafenib was associated with a significantly increased risk of all-grade rash (RR 1.35, 95% CI 1.01 to 1.80) and a decreased risk of cSCC (RR 0.40, 95% CI 0.18 to 0.89), alopecia (RR 0.19, 95% CI 0.12 to 0.30) and HK (RR 0.25, 95% CI 0.10 to 0.62).

CONCLUSION

In summary, the most frequent cutaneous adverse reactions from dabrafenib were rash, cSCC, alopecia, KA, HK and pruritus. There was a significantly decreased risk of cSCC, alopecia and HK with the combination of dabrafenib with trametinib versus dabrafenib alone. Clinicians should be aware of these risks and perform regular clinical monitoring.

Circulating Tumor DNA as a Marker for Treatment Response in Metastatic Melanoma Patients Using Next-Generation Sequencing-A Prospective Feasibility Study

We prospectively performed a longitudinal analysis of circulating tumor DNA (ctDNA) from 149 plasma samples and CT scans in Stage III and IV metastatic melanoma patients (n = 20) treated with targeted agents or immunotherapy using two custom next-generation sequencing (NGS) Ion AmpliSeq™ HD panels including 60 and 81 amplicons in 18 genes, respectively. Concordance of matching cancer-associated mutations in tissue and plasma was 73.3%. Mutant allele frequency (MAF) levels showed a range from 0.04% to 28.7%, well detectable with NGS technologies utilizing single molecule tagging like the AmpliSeq™ HD workflow. Median followup time of the tissue and/or plasma positive cohort (n = 15) was 24.6 months and median progression-free survival (PFS) was 7.8 months. Higher MAF ≥ 1% at baseline was not significantly associated with a risk of progression (Odds Ratio = 0.15; p = 0.155). Although a trend could be seen, MAF levels did not differ significantly over time between patients with and without a PFS event (p = 0.745). Depending on the cell-free DNA amount, NGS achieved a sensitivity down to 0.1% MAF and allowed for parallel analysis of multiple mutations and previously unknown mutations. Our study indicates that NGS gene panels could be useful for monitoring disease burden during therapy with ctDNA in melanoma patients.

Longitudinal assessment of B-RAF V595E levels in the peripheral cell-free tumor DNA of a 10-year-old spayed female Korean Jindo dog with unresectable metastatic urethral transitional cell carcinoma for monitoring the treatment response to a RAF inhibitor (sorafenib)

Transitional cell carcinoma (TCC) is the most common malignant tumor of the canine urinary tract. In this case study, a dog with metastatic urethral TCC was treated with sorafenib. The tumor expression levels of receptor tyrosine kinase genes, including VEGFR-1, VEGFR-2, PDGFR-α, PDGFR-β, ALK, EGFR, ErbB2, and B-RAF, were analyzed. VEGFR was overexpressed in tumor tissues compared to the normal tissues. Considering the high frequency of B-RAF mutation in canine urological tumors, the B-RAF gene was examined, and the B-RAF V595E mutation was detected in the tumor tissue. Therefore, the antitumor effect of sorafenib, a multi-tyrosine kinase inhibitor, on unresectable metastatic urethral TCC characterized by B-RAF V595E was evaluated and circulating cell-free tumor DNA (ctDNA) was assessed for monitoring the treatment response. After the initiation of oral sorafenib therapy (4 mg/kg/day escalated to 10 mg/kg/day), the dysuria was alleviated gradually, and the patient remained stable for 3 months. During that treatment period, the patient showed various levels of changes associated with B-RAF V595E mutation in ctDNA as evident from longitudinal plasma samples after initiation of sorafenib therapy. The findings of this study suggest that ctDNA may serve as a useful non-invasive tool for monitoring the treatment response to anticancer drugs.

Case Report: Rechallenge With BRAF and MEK Inhibitors in Metastatic Melanoma: A Further Therapeutic Option in Salvage Setting?

BACKGROUND

The combination of BRAF and MEK inhibitors represents the standard of care treatment for patients with metastatic BRAF-mutated melanoma, notwithstanding the high frequency of emergent resistance. Moreover, therapeutic options outside clinical trials are scarce when patients have progressed after both targeted therapy and therapy with immune checkpoint inhibitors. In this article, we report our experience with targeted therapy rechallenging with BRAF and MEK inhibitors in patients with metastatic BRAF-mutated melanoma after progression with kinase inhibitors and immunotherapy.

METHODS

Four patients with metastatic BRAF-mutated melanoma were rechallenged with BRAF and MEK inhibitors after progression with targeted therapy and subsequent immunotherapy (checkpoint inhibitors).

RESULTS

Two patients (one of them was heavily pretreated) had partial response over 36 months (with local treatment on oligoprogression disease) and 10 months, respectively. A third patient with multisite visceral disease and high serum levels of lactate dehydrogenase had a short-lived clinical benefit rapidly followed by massive progression of disease (early progressor). The fourth patient, currently on treatment with BRAF/MEK inhibitors, is showing a clinical benefit and radiological stable disease over 3 months of therapy. Adverse events were manageable, similar to those reported during the first targeted therapy; the treatment was better tolerated at rechallenge compared with the first treatment by two out of four patients.

Phase I-II Open-Label Multicenter Study of Palbociclib + Vemurafenib in BRAF V600MUT Metastatic Melanoma Patients: Uncovering CHEK2 as a Major Response Mechanism

PURPOSE

In BRAF ^V600MUT metastatic melanoma, cyclin D-CDK4/6-INK4-Rb pathway alterations are involved in resistance to MAPK inhibitors, suggesting a clinical benefit of cyclin-dependent kinase 4 (CDK4) inhibitors. In this phase I-II study, we aimed to establish the MTD of palbociclib when added to vemurafenib.

PATIENTS AND METHODS

Patients with BRAF ^V600E/KMUT metastatic melanoma harboring CDKN2A loss and RB1 expression were included and stratified into two groups according to previous BRAF inhibitor treatment (no:strata 1; yes:strata 2). Treatment comprised palbociclib once daily for 14 days followed by a 7-day break + continuous dosing of vemurafenib. The primary endpoint was the occurrence of dose-limiting toxicity (DLT), and the secondary endpoints included the best response, survival, pharmacokinetics, and tumor molecular profiling.

RESULTS

Eighteen patients were enrolled, with 15 in strata 2. Characteristics at inclusion were American Joint Committee on Cancer stage IVM1c (N = 16; 88.9%), high lactate dehydrogenase (N = 9; 50.0%), and median number of previous treatments of 2. One and 5 patients experienced DLT in strata 1 and 2, respectively, defining the MTD at palbociclib 25 mg and vemurafenib 960 mg in strata 2. No significant evidence for drug-drug interactions was highlighted. The median progression-free survival was 2.8 months, and 5 (27.8%) patients showed a clinical response. The baseline differential mRNA expression analysis and in vitro data revealed the role of CHEK2 in the response to palbociclib.

CONCLUSIONS

Although the combination of palbociclib + fixed-dose vemurafenib did not allow an increased palbociclib dosage above 25 mg, a significant clinical benefit was achieved in pretreated patients with melanoma. An association between the transcriptomic data and clinical response was highlighted.