Rechallenge with BRAF-directed treatment in metastatic melanoma: A multi-institutional retrospective study

Clinical Applications of the Molecular Landscape of Melanoma: Integration of Research into Diagnostic and Therapeutic Strategies

The molecular landscape of cutaneous melanoma is complex and heterogeneous, and a deeper understanding of the genesis and progression of the tumor driven by genetic alterations is essential for the development of effective diagnostic and therapeutic strategies. Molecular diagnostics and the use of biomarkers are increasingly playing a role in treatment decisions. However, further research is urgently needed to elucidate the relationships between complex genetic alterations and the effectiveness of target therapies (although BRAF mutation is still the only targeted genetic alteration). Further research is required to exploit other targetable genetic alterations such as NRAS, KIT or rare mutations. Treatment guidelines for cutaneous melanoma are continually evolving based on data from recent and ongoing clinical trials. These advancements reflect changes mainly in the optimal timing of systemic therapy and the choice of combination therapies increasingly tailored to molecular profiles of individual tumors. Mono- or combination immunotherapies demonstrated unprecedented success of melanoma treatment; still, there is room for improvement: though several factors of primary or acquired resistance are known, they are not part of patient management as biomarkers. The novel developments of cancer vaccines to treat melanoma (melanoma-marker-based or personalized neoantigen-based) are encouraging; introduction of them into clinical practice without proper biomarkers would be the same mistake made in the case of first-generation immunotherapies.

BRAF and MEK inhibitors rechallenge after an adverse drug reaction in patients with cancer: A pharmacovigilance cohort study

IMPORTANCE

The safety profile of a rechallenge with BRAF inhibitors (BRAFi) or a combination of BRAF and MEK inhibitors (MEKi) following an adverse drug reaction (ADR) remains largely unexplored.

OBJECTIVE

To identify the reported recurrence rate of the same ADR after a BRAFi±MEKi targeted therapy (TT) rechallenge in patients with cancer and to identify factors associated with recurrence.

DESIGN, SETTING, AND PARTICIPANTS

In this observational, pharmacovigilance study, ADR reports were sourced from VigiBase, the World Health Organization database. The inclusion criteria encompassed all BRAFi cases (with or without MEKi) through September 01, 2023, irrespective of the primary cancer diagnosis.

MAIN OUTCOMES AND MEASURES

The primary outcome was the reported recurrence rate of the same initial ADR following TT rechallenge. Secondary outcomes measures included were identification of variables associated with recurrence among informative rechallenges, defined as those with known recurrence status.

RESULTS

Out of 21,339 ADR cases linked to TT, 4771 (22.4%) reported a rechallenge, with 563 yielding informative data (11.8%). Recurrence of the initial ADR was reported in 223 cases, resulting in a reported recurrence rate of 39.6% (95% CI: 35.7-43.7). The highest recurrence rates in a rechallenge were observed for pyrexia (47%, 95% CI: 39-55), renal failure (46%, 95% CI: 32-60), and musculoskeletal disorders (44%, 95%CI: 33-56). There was no significant influence of factors such as TT regimen (either BRAFi monotherapy or any TT combination), age, sex, or the type of cancer on reported recurrence rate.

CONCLUSIONS AND RELEVANCE

In real-world settings, approximately two-fifths of cases with notified TT rechallenges led to a reporting of recurrence of the same initial ADR. The primary determinant of reported recurrence seems to be the nature of the initial ADR rather than the TT regimen, or any other baseline patient characteristic.

SEOM-GEM clinical guidelines for cutaneous melanoma (2023)

Cutaneous melanoma incidence is rising. Early diagnosis and treatment administration are key for increasing the chances of survival. For patients with locoregional advanced melanoma that can be treated with complete resection, adjuvant-and more recently neoadjuvant-with targeted therapy-BRAF and MEK inhibitors-and immunotherapy-anti-PD-1-based therapies-offer opportunities to reduce the risk of relapse and distant metastases. For patients with advanced disease not amenable to radical treatment, these treatments offer an unprecedented increase in overall survival. A group of medical oncologists from the Spanish Society of Medical Oncology (SEOM) and Spanish Multidisciplinary Melanoma Group (GEM) has designed these guidelines, based on a thorough review of the best evidence available. The following guidelines try to cover all the aspects from the diagnosis-clinical, pathological, and molecular-staging, risk stratification, adjuvant therapy, advanced disease therapy, and survivor follow-up, including special situations, such as brain metastases, refractory disease, and treatment sequencing. We aim help clinicians in the decision-making process.

Real-world efficacy and safety of BRAF-targeted therapy for patients with advanced melanoma: A single-center retrospective study in Japan

Most clinical trials investigating targeted therapies for patients harboring BRAF V600 mutations have included mostly White patients, and data for Asian patients are scarce. Although there are several retrospective studies in Japanese patients, they have investigated only the dabrafenib + trametinib regimen, and have had a short follow-up period. We conducted a single-center retrospective study to update previous studies and compare the outcomes with those in White patients. We analyzed 89 patients who received dabrafenib + trametinib or encorafenib + binimetinib, including 11 who received both treatment regimens. The overall response rate was 79.8%, with complete response in 25 patients (28.1%) and partial response in 45 patients (51.7%). The median progression-free survival was 13.7 months, and the median overall survival was 32.9 months. The 3-year progression-free and overall survival rates were 31.8% and 47.9%, respectively. Although the two regimens showed no significant differences in efficacy, their safety profiles differed, as reported in clinical trials. Therefore, the most frequent adverse event associated with the dabrafenib + trametinib regimen was pyrexia (61.3%) and that of encorafenib + binimetinib was blurred vision (32.0%). Switching directly to another targeted therapy after progressive disease showed no clinical response; however, rechallenge followed by immune checkpoint inhibitor therapy showed a certain response. As a prognostic factor, performance status was associated with progression-free survival, and performance status, serum lactate dehydrogenase level, and dose interruption were associated with overall survival in the multivariate analysis. Real-world data on targeted therapy for patients with melanoma in Japan suggest that both dabrafenib + trametinib and encorafenib + binimetinib show similar efficacy and safety in Asian and White patients.

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.

BRAF/MEK inhibitor rechallenge in advanced melanoma patients

BACKGROUND

Effectivity of BRAF(/MEK) inhibitor rechallenge has been described in prior studies. However, structured data are largely lacking.

METHODS

Data from all advanced melanoma patients treated with BRAFi(/MEKi) rechallenge were retrieved from the Dutch Melanoma Treatment Registry. The authors analyzed objective response rate (ORR), progression-free survival (PFS), and overall survival (OS) for both first treatment and rechallenge. They performed a multivariable logistic regression and a multivariable Cox proportional hazards model to assess factors associated with response and survival.

RESULTS

The authors included 468 patients in the largest cohort to date who underwent at least two treatment episodes of BRAFi(/MEKi). Following rechallenge, ORR was 43%, median PFS was 4.6 months (95% confidence interval [CI], 4.1-5.2), and median OS was 8.2 months (95% CI, 7.2-9.4). Median PFS after rechallenge for patients who discontinued first BRAFi(/MEKi) treatment due to progression was 3.1 months (95% CI, 2.7-4.0) versus 5.2 months (95% CI, 4.5-5.9) for patients who discontinued treatment for other reasons. Discontinuing first treatment due to progression and lactate dehydrogenase (LDH) levels greater than two times the upper limit of normal were associated with lower odds of response and worse PFS and OS. Symptomatic brain metastases were associated with worse survival, whereas a longer treatment interval between first treatment and rechallenge was associated with better survival. Responding to the first BRAFi(/MEKi) treatment was not associated with response or survival.

CONCLUSIONS

This study confirms that patients benefit from rechallenge. Elevated LDH levels, symptomatic brain metastases, and discontinuing first BRAFi(/MEKi) treatment due to progression are associated with less benefit from rechallenge. A prolonged treatment interval is associated with more benefit from rechallenge.

RAF inhibitor re-challenge therapy in BRAF-aberrant pan-cancers: the RE-RAFFLE study

Previous studies have shown the clinical benefit of rechallenging the RAF pathway in melanoma patients previously treated with BRAF inhibitors. 44 patients with multiple tumors harboring RAF alterations were rechallenged with a second RAF inhibitor, either as monotherapy or in combination with other therapies, after prior therapy with a first RAF inhibitor. This retrospective observational study results showed that rechallenging with RAFi(s) led to an overall response rate of 18.1% [PR in thyroid (1 anaplastic; 3 papillary), 1 ovarian, 2 melanoma, 1 cholangiocarcinoma, and 1 anaplastic astrocytoma]. The clinical benefit rate was 54.5%; more than 30% of patients had durable responses with PR and SD lasting > 6 months. The median progression-free survival on therapy with second RAF inhibitor in the rechallenge setting either as monotherapy or combination was shorter at 2.7 months (0.9-30.1 m) compared to 8.6 months (6.5-11.5 m) with RAF-1i. However, the median PFS with RAF-2i responders (PFS-2) improved at 12.8 months compared to 11.4 months with RAF-1i responders. The median OS from retreatment with RAF-2i was 15.5 months (11.1-30.8 m). Further prospective studies are needed to validate these results and expand targeted therapy options for RAF-aberrant cancers.

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.

Investigational Approaches for Treatment of Melanoma Patients Progressing After Standard of Care

ABSTRACT

The advent of effective immunotherapy, specifically cytotoxic T-lymphocyte associated protein 4 and programmed cell death 1 inhibitors, as well as targeted therapy including BRAF/MEK inhibitors, has dramatically changed the prognosis for metastatic melanoma patients. Up to 50% of patients may experience long-term survival currently. Despite these advances in melanoma treatment, many patients still progress and die of their disease. As such, there are many studies aimed at providing new treatment options for this population. Therapies currently under investigation include, but are not limited to, novel immunotherapies, targeted therapies, tumor-infiltrating lymphocytes and other cellular therapies, oncolytic viral therapy and other injectables, and fecal microbiota transplant. In this review, we discuss the emerging treatment options for metastatic melanoma patients who have progressed on standard of care treatments.

Pediatric low-grade glioma: State-of-the-art and ongoing challenges

The most common childhood central nervous system (CNS) tumor is pediatric low-grade glioma (pLGG), representing 30%-40% of all CNS tumors in children. Although there is high associated morbidity, tumor-related mortality is relatively rare. pLGG is now conceptualized as a chronic disease, underscoring the importance of functional outcomes and quality-of-life measures. A wealth of data has emerged about these tumors, including a better understanding of their natural history and their molecular drivers, paving the way for the use of targeted inhibitors. While these treatments have heralded tremendous promise, challenges remain about how to best optimize their use, and the long-term toxicities associated with these inhibitors remain unknown. The International Pediatric Low-Grade Glioma Coalition (iPLGGc) is a global group of physicians and scientists with expertise in pLGG focused on addressing key pLGG issues. Here, the iPLGGc provides an overview of the current state-of-the-art in pLGG, including epidemiology, histology, molecular landscape, treatment paradigms, survival outcomes, functional outcomes, imaging response, and ongoing challenges. This paper also serves as an introduction to 3 other pLGG manuscripts on (1) pLGG preclinical models, (2) consensus framework for conducting early-phase clinical trials in pLGG, and (3) pLGG resistance, rebound, and recurrence.

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.

Long-term outcomes and persistent toxicities following BRAF/MEK inhibitor therapy for advanced melanoma

BACKGROUND

Recent studies have shown that approximately 20% of patients have 4-5 year progression free survival (PFS) on BRAF/MEK inhibitors. The long-term safety and efficacy in these patients with more durable responses have not been studied.

METHODS

This retrospective multicenter cohort study assessed response, progression, and adverse events in patients from eight institutions in four countries with >4-year PFS following BRAF/MEK inhibitors.

RESULTS

Among 146 patients, 112 (76.7%) remained progression-free at median follow-up of 7.8 years from treatment start; 131 (89.7%) were alive. Among progressors (n = 34), 21 (62%) were on treatment at progression. Among those who discontinued treatment for reasons other than progression (toxicity, preference, etc.) (n = 68, with median 49 months treatment duration), 13 (19%) progressed (median 15.3 months from treatment cessation to progression). Surgery or radiation for single-organ progression resulted in durable benefit in 11 of 22 patients (50%). Subsequent systemic therapy included immune therapy (24% responded) and BRAF/MEK rechallenge (56% responded). Thirteen (8.9%) patients had ongoing toxicities at last follow-up, 10 (77%) of which remained on active treatment; all cardiac adverse events had resolved (n = 9). Twenty-four (16.4%) patients developed any new primary cancer, and 28 (19%) patients experienced other major health events.

CONCLUSIONS

Over 75% of patients with 4-year PFS from BRAF/MEK inhibitors had continued durable antitumor responses after nearly 8-year median follow-up, with similar results in patients who discontinued therapy for reasons other than progression. Long-term toxicities were uncommon and low-grade. These findings highlight the often-favourable outcomes in patients with extended benefit from BRAF/MEK inhibitors.

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.

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.

Burden and Risk Factors of Brain Metastases in Melanoma: A Systematic Literature Review

Melanoma can frequently metastasize to the brain with severe consequences. However, variation of melanoma brain metastases (MBM) development among populations is not well studied, and underlying mechanisms and risk factors for MBM development are not consistently documented. We conducted a systematic literature review (SLR) including a total of 39 articles to evaluate the proportion of melanoma patients who are diagnosed with, or develop, brain metastases, and summarize the risk factors of MBM. The average proportion of MBM was calculated and weighted by the sample size of each study. Meta-analyses were conducted for the selected risk factors using a random-effects model. The proportion of MBM at diagnosis was 33% (975 with MBM out of 2948 patients) among patients with cutaneous melanoma (excluding acral) and 23% (651/2875) among patients with cutaneous mixed with other types of melanoma. The proportion at diagnosis was lower among populations with mucosal (9/96, 9%) or uveal (4/184, 2%) melanoma and among populations outside the United States and Europe. Meta-analysis demonstrated that male vs. female gender and left-sided tumors vs. right-sided were significantly associated with increased risk of melanoma brain metastases. These data may help clinicians to assess an individual patient's risk of developing melanoma brain metastases.

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.

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.

Impact of electrochemotherapy in metastatic cutaneous melanoma: a contemporary systematic review and meta-analysis

BACKGROUND

Electrochemotherapy (ECT) harnesses electric pulses to enhance cytotoxic drug delivery into tumors and has entered the armamentarium to treat superficially metastatic melanoma. We performed a systematic review and meta-analysis to assess treatment patterns and patient outcomes.

METHODS

PubMed, Medline, Embase, and the Cochrane Library databases were queried for publication from inception to September 2020. Primary outcome measures were overall and complete response rate (ORR and CRR); secondary outcomes included local control rate (LCR) and overall survival (OS).

RESULTS

Twenty-seven studies met the selection criteria for a total of 1161 individuals (mean age 71 years) and 5308 tumors (weighted mean size 14 mm). The majority of patients (n = 1124) underwent bleomycin-ECT. Aggregate ORR was 77.6% (95% confidence interval [CI] 71.0 - 83.2%) and CRR 48% (95% CI 42 - 54%), with no significant difference between the route of bleomycin administration (ORR, 69.2 vs. 81.9% following intravenous or intratumoral bleomycin, p = .37) and tumor size (p = .69). When reported (n = 8 studies), 1- and 2-year LCR ranged from 54 to 89% and 72 to 74%, respectively, and 1-year OS (n = 3 studies) from 67 to 89%.

CONCLUSIONS

ECT with either intratumoral or intravenous bleomycin confers a high therapeutic response in cutaneous metastatic melanoma. Moderate evidence supports its low toxicity and durability of local control.HighlightsElectrochemotherapy (ECT) is associated with a 77% overall response rate (ORR).Intravenous and intratumoral bleomycin are equally effective.There are no relevant toxicity concerns.One-year local tumor control rate ranges from 54 to 89%.Current literature has significant variation in reporting.

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.

Anti-tumor treatment and healthcare consumption near death in the era of novel treatment options for patients with melanoma brain metastases

Background

Effective systemic treatments have revolutionized the management of patients with metastatic melanoma, including those with brain metastases. The extent to which these treatments influence disease trajectories close to death is unknown. Therefore, this study aimed to gain insight into provided treatments and healthcare consumption during the last 3 months of life in patients with melanoma brain metastases.

Methods

Retrospective, single-center study, including consecutive patients with melanoma brain metastases diagnosed between June-2015 and June-2018, referred to the medical oncologist, and died before November-2019. Patient and tumor characteristics, anti-tumor treatments, healthcare consumption, presence of neurological symptoms, and do-not-resuscitate status were extracted from medical charts.

Results

100 patients were included. A BRAF-mutation was present in 66 patients. Systemic anti-tumor therapy was given to 72% of patients during the last 3 months of life, 34% in the last month, and 6% in the last week. Patients with a BRAF-mutation more frequently received systemic treatment during the last 3 (85% vs. 47%) and last month (42% vs. 18%) of life than patients without a BRAF-mutation. Furthermore, patients receiving systemic treatment were more likely to visit the emergency room (ER, 75% vs. 36%) and be hospitalized (75% vs. 36%) than those who did not.

Conclusion

The majority of patients with melanoma brain metastases received anti-tumor treatment during the last 3 months of life. ER visits and hospitalizations occurred more often in patients on anti-tumor treatment. Further research is warranted to examine the impact of anti-tumor treatments close to death on symptom burden and care satisfaction.

Targeted therapy strategies for melanoma brain metastasis

Melanoma is the most aggressive of the common forms of skin cancer. Metastasis to the central nervous system is one of the most common and deadly complications of this disease. Historically, melanoma patients with brain metastases had a median survival of less than 6 months. However, outcomes of melanoma patients have markedly improved over the last decade due to new therapeutic approaches, including immune and targeted therapies. Targeted therapies leverage the high rate of driver mutations in this disease, which result in the activation of multiple key signaling pathways. The RAS-RAF-MEK-ERK pathway is activated in the majority of cutaneous melanomas, most commonly by point mutations in the Braf serine-threonine kinase. While most early targeted therapy studies excluded melanoma patients with brain metastases, subsequent studies have shown that BRAF inhibitors, now generally given concurrently with MEK inhibitors, achieve high rates of tumor response and disease control in Braf-mutant melanoma brain metastases (MBMs). Unfortunately, the duration of these responses is generally relatively short- and shorter than is observed in extracranial metastases. This review will summarize current data regarding the safety and efficacy of targeted therapies for MBMs and discuss rational combinatorial strategies that may improve outcomes further.

Epigenetic Regulation in Melanoma: Facts and Hopes

Cutaneous melanoma is a lethal disease, even when diagnosed in advanced stages. Although recent progress in biology and treatment has dramatically improved survival rates, new therapeutic approaches are still needed. Deregulation of epigenetics, which mainly controls DNA methylation status and chromatin remodeling, is implied not only in cancer initiation and progression, but also in resistance to antitumor drugs. Epigenetics in melanoma has been studied recently in both melanoma preclinical models and patient samples, highlighting its potential role in different phases of melanomagenesis, as well as in resistance to approved drugs such as immune checkpoint inhibitors and MAPK inhibitors. This review summarizes what is currently known about epigenetics in melanoma and dwells on the recognized and potential new targets for testing epigenetic drugs, alone or together with other agents, in advanced melanoma patients.

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.

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.

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.

Survival of advanced melanoma patients treated with immunotherapy and targeted therapy: A real-world study

INTRODUCTION

We aimed to examine the survival outcomes plus patient and treatment characteristics of advanced melanoma patients treated with first-line immunotherapy (IT), targeted therapy (TT), and chemotherapy (CTH) and compare findings with information from pivotal trials for each therapy.

MATERIALS AND METHODS

We retrospectively reviewed the use of systematic IT, TT and CTH therapies in melanoma patients in four Queensland public hospitals. We estimated median duration of overall survival (OS) and survival rates (6 months, 1, and 2 years) using Kaplan-Meier methods. We compared our findings to those of clinical trials.

RESULTS

Five hundred three patients who met the inclusion criteria were divided into three groups based on the first-line treatment: IT 232; TT 157; and CTH 114. OS was 18 months with IT (95% CI 13, 22); 12 months with TT (95% CI 8, 15); and 5 months with CTH (95% CI 5, 6). The demographic characteristics, treatment protocols, and durations for IT and TT were generally consistent with trials but fewer patients in our study had subsequent therapy than in the trials. The OS in our study was slightly lower than the OS reported in trials.

CONCLUSION

The OS of novel cancer therapy in the real world was lower than seen in trials but is expected given these are patients who have a poorer prognosis. A future study could investigate the impact of prognostic factors on survival in the longer term. This study provides evidence that we can use routinely collected real-world data to evaluate the effectiveness of checkpoint and kinase inhibitors in patients with advanced melanoma.

Defining and Targeting BRAF Mutations in Solid Tumors

OPINION STATEMENT

BRAF mutations are present in up to 8% of human cancers, and comprise a viable therapeutic target in many patients harboring these mutations. Specific BRAF-targeted therapies, such as vemurafenib, dabrafenib, and encorafenib, have transformed treatment of many BRAF-mutated cancers, producing meaningful clinical benefit with more tolerable safety profiles compared to prior standard-of-care treatments. BRAF inhibitors were first approved for use in metastatic melanoma, although resistance almost always limited their long-term effectiveness. Combination therapy with BRAF and MEK inhibitors has proven effective in delaying the onset of resistance, and produces additional clinical benefit across cancers. Although not promising initially in treatment of BRAF-mutated colorectal carcinoma, BRAF inhibitors in colorectal cancer were successfully combined with EGFR inhibitors, resulting in significant treatment response. Refining the use of BRAF and MEK inhibitors in less common tumor types (and for non-V600 mutations) and delaying the development of resistance remain pertinent future considerations in treating BRAF-mutated cancers. In this review, we will discuss the prevalence of BRAF mutations across human cancers and evidence on the efficacy and safety of current management strategies for various BRAF-mutant solid tumors.

Melanoma recurrence patterns and management after adjuvant targeted therapy: a multicentre analysis

BACKGROUND

Adjuvant targeted therapy (TT) improves relapse free survival in patients with resected BRAF mutant stage III melanoma. The outcomes and optimal management of patients who relapse after adjuvant TT is unknown.

METHODS

Patients from twenty-one centres with recurrent melanoma after adjuvant TT were included. Disease characteristics, adjuvant therapy, recurrence, treatment at relapse and outcomes were examined.

RESULTS

Eighty-five patients developed recurrent melanoma; nineteen (22%) during adjuvant TT. Median time to first recurrence was 18 months and median follow-up from first recurrence was 31 months. Fifty-eight (68%) patients received immunotherapy (IT) or TT as 1st line systemic therapy at either first or subsequent recurrence and had disease that was assessable for response. Response to anti-PD-1 (±trial agent), combination ipilimumab-nivolumab, TT rechallenge and ipilimumab monotherapy was 63%, 62% 25% and 10% respectively. Twenty-eight (33%) patients had died at census, all from melanoma. Two-year OS was 84% for anti-PD-1 therapy (±trial agent), 92% for combination ipilimumab and nivolumab, 49% for TT and 45% for ipilimumab monotherapy (p = 0.028).

CONCLUSIONS

Patients who relapse after adjuvant TT respond well to subsequent anti-PD-1 based therapy and have outcomes similar to those seen when first line anti-PD-1 therapy is used in stage IV melanoma.

Clinical Implications of Acquired BRAF Inhibitors Resistance in Melanoma

Understanding the role of mitogen-activated protein kinase (MAPK) pathway-activating mutations in the development and progression of melanoma and their possible use as therapeutic targets has substantially changed the management of this neoplasm, which, until a few years ago, was burdened by severe mortality. However, the presence of numerous intrinsic and extrinsic mechanisms of resistance to BRAF inhibitors compromises the treatment responses’ effectiveness and durability. The strategy of overcoming these resistances by combination therapy has proved successful, with the additional benefit of reducing side effects derived from paradoxical activation of the MAPK pathway. Furthermore, the use of other highly specific inhibitors, intermittent dosing schedules and the association of combination therapy with immune checkpoint inhibitors are promising new therapeutic strategies. However, numerous issues related to dose, tolerability and administration sequence still need to be clarified, as is to be expected from currently ongoing trials. In this review, we describe the clinical results of using BRAF inhibitors in advanced melanoma, with a keen interest in strategies aimed at overcoming resistance.

Stopping targeted therapy for complete responders in advanced BRAF mutant melanoma

BRAF inhibitors revolutionised the management of melanoma patients and although resistance occurs, there is a subgroup of patients who maintain durable disease control. For those cases with durable complete response (CR) it is not clear whether it is safe to cease therapy. Here we identified 13 patients treated with BRAF +/- MEK inhibitors, who cease therapy after prolonged CR (median = 34 months, range 20-74). Recurrence was observed in 3/13 (23%) patients. In the remaining 10 patients with sustained CR off therapy, the median follow up after discontinuation was 19 months (range 8-36). We retrospectively measured ctDNA levels using droplet digital PCR (ddPCR) in longitudinal plasma samples. CtDNA levels were undetectable in 11/13 cases after cessation and remained undetectable in patients in CR (10/13). CtDNA eventually became detectable in 2/3 cases with disease recurrence, but remained undetectable in 1 patient with brain only progression. Our study suggests that consideration could be given to ceasing targeted therapy in the context of prolonged treatment, durable response and no evidence of residual disease as measured by ctDNA.

Response to re-challenge of a MEK inhibitor in a patient with recurrent low-grade serous carcinoma of the peritoneum

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Low-grade serous carcinoma is relatively resistant to chemotherapy.

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MEK inhibitors have promising activity in recurrent low-grade serous carcinoma.

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The first case of successful re-challenge with a MEK inhibitor is presented.

Low-grade serous carcinoma of the ovary/peritoneum is a rare epithelial cancer subtype characterized by younger age at diagnosis, relative chemoresistance, and prolonged overall survival compared with high-grade serous carcinoma. In addition, alterations in the mitogen activated protein kinase pathway are frequent and play a major role in the pathogenesis of this tumor. MEK inhibitors have demonstrated promising activity in the treatment of recurrent low-grade serous carcinoma. Although prevailing wisdom in cancer therapy is that the re-treatment with a drug after emergence of resistance is futile, we report the initial case of a patient with recurrent low-grade serous carcinoma who experienced a partial response when re-challenged with a MEK inhibitor after previously having prolonged stable disease followed by disease progression on a MEK inhibitor.

ESMO consensus conference recommendations on the management of metastatic melanoma: under the auspices of the ESMO Guidelines Committee

The European Society for Medical Oncology (ESMO) held a consensus conference on melanoma on 5-7 September 2019 in Amsterdam, The Netherlands. The conference included a multidisciplinary panel of 32 leading experts in the management of melanoma. The aim of the conference was to develop recommendations on topics that are not covered in detail in the current ESMO Clinical Practice Guideline and where available evidence is either limited or conflicting. The main topics identified for discussion were (i) the management of locoregional disease; (ii) targeted versus immunotherapies in the adjuvant setting; (iii) targeted versus immunotherapies for the first-line treatment of metastatic melanoma; (iv) when to stop immunotherapy or targeted therapy in the metastatic setting; and (v) systemic versus local treatment for brain metastases. The expert panel was divided into five working groups to each address questions relating to one of the five topics outlined above. Relevant scientific literature was reviewed in advance. Recommendations were developed by the working groups and then presented to the entire panel for further discussion and amendment before voting. This manuscript presents the results relating to the management of metastatic melanoma, including findings from the expert panel discussions, consensus recommendations and a summary of evidence supporting each recommendation. All participants approved the final manuscript.

Rechallenge with dabrafenib plus trametinib in anaplastic thyroid cancer: A case report and review of literature

INTRODUCTION

Anaplastic thyroid carcinoma (ATC) is a highly aggressive, undifferentiated rare tumor. Median overall survival is usually between 8 and10 months, with a 1-year survival rate of 20%. Conventional anthracycline based chemotherapy regimens demonstrate low response rates with short duration. Novel therapeutic agents including BRAF and MEK inhibitors based on the molecular landscape of ATC have been investigated.

CASE PRESENTATION

We herein report the rechallenge of a 52-year-old ATC patient with BRAF V600E mutation with dabrafenib plus trametinib. She presented with recurrent and progressive disease despite surgery, radiation therapy, 3 different chemotherapy regimens, and combination of dabrafenib-trametinib in different settings. She was rechallenged with dabrafenib-trametinib, and had a good response.

CONCLUSION

To our knowledge, this is the first ATC case who responded to dabrafenib-trametinib rechallenge, reported in the literature. We want to emphasize that combination of dabrafenib and trametinib might be a good choice for resistant locoregional and metastatic ATC patients with BRAF V600E mutation, particularly in whom rapid clinical response is urgently needed. Moreover, rechallenge with this combination should be kept in mind in selected cases.

Continuous versus intermittent BRAF and MEK inhibition in patients with BRAF-mutated melanoma: a randomized phase 2 trial

Preclinical modeling suggests that intermittent BRAF inhibitor therapy may delay acquired resistance when blocking oncogenic BRAFV600 in melanoma1,2. We conducted S1320, a randomized, open-label, phase 2 clinical trial (NCT02196181) evaluating whether intermittent dosing of the BRAF inhibitor dabrafenib and the MEK inhibitor trametinib improves progression-free survival in patients with metastatic and unresectable BRAFV600 melanoma. Patients were enrolled at 68 academic and community sites nationally. All patients received continuous dabrafenib and trametinib during an 8-week lead-in period, after which patients with non-progressing tumors were randomized to either continuous or intermittent dosing of both drugs on a 3-week-off, 5-week-on schedule. The trial has completed accrual and 206 patients with similar baseline characteristics were randomized 1:1 to the two study arms (105 to continuous dosing, 101 to intermittent dosing). Continuous dosing yielded a statistically significant improvement in post-randomization progression-free survival compared with intermittent dosing (median 9.0 months versus 5.5 months, P = 0.064, pre-specified two-sided α = 0.2). Therefore, contrary to the initial hypothesis, intermittent dosing did not improve progression-free survival in patients. There were no differences in the secondary outcomes, including overall survival and the overall incidence of treatment-associated toxicity, between the two groups.

Retreatment with talimogene laherparepvec for advanced melanoma

Aim: Talimogene laherparepvec (T-VEC) is a genetically modified oncolytic herpesvirus approved for the treatment of unresectable, locoregionally advanced and recurrent melanoma. There is little relevant literature in the context of retreatment with T-VEC. Materials & methods: We reviewed four patients aged 71-87 years old with stage IIIB-IV melanoma at treatment who were rechallenged with T-VEC after experiencing recurrence of locoregional disease or prior treatment-limiting toxicity. Results: Cessation of initial treatment was due to one of the following reasons: severe adverse event (one case), mixed response (one case) or complete response (two cases). Three males and one female underwent T-VEC retreatment with a mean of 5.5 injection cycles. Three patients experienced a complete response to retreatment, while one experienced disease progression. Conclusion: Intralesional T-VEC may be effective and well-tolerated in patients who have completed prior T-VEC therapy.

The Systemic Treatment of Melanoma

BACKGROUND

The systemic treatment of metastatic melanoma has improved considerably with the introduction of new, targeted substances and immune checkpoint inhibitors. This article presents treatment options for advanced inoperable melanoma and in the setting of adjuvant treatment after complete metastasectomy.

METHODS

The data for analysis were derived from a selective literature search in PubMed and a search for systematic reviews in the Cochrane Library.

RESULTS

Immune checkpoint inhibitors, which target the cytotoxic T-lymphocyte antigen or the "programmed death" (PD) receptor, activate T-cells and other immune cells, so that the body's own immune system attacks the melanoma. In unselected patients, immune checkpoint inhibition using nivolumab improved overall survival compared with dacarbazine (hazard ratio [HR]: 0.42; P<0.001). The antibody pem- brolizumab also led to better overall survival than ipilimumab (HR 0.68; P<0.001). Combination treatment with anti-CTLA-4 and anti-PD-1 antibodies improved overall survival even more than ipilimumab monotherapy, albeit at the cost of greater toxic- ity (HR 0.55; P<0.001). Another treatment approach aims to inhibit intracellular signal transduction in the melanoma cells. For patients with a BRAF-V66 mutation, combination treatments with BRAF/MEK inhibitors led to a rapid response in most cases (64-75%). In principle, the novel treatments are also effective in patients with cerebral metastases. In the adjuvant setting, both immune checkpoint inhibitors and BRAF/MEK inhibitors reduced the risk of recurrence by about 50%.

CONCLUSION

High-quality studies show that the new substances are clinically effective in the palliative and adjuvant treatment of melanoma.

Melanoma Brain Metastases in the Era of Target Therapies: An Overview

Malignant melanoma is the third most common type of tumor that causes brain metastases. Patients with cerebral involvement have a dismal prognosis and their treatment is an unmet medical need. Brain involvement is a multistep process involving several signaling pathways such as Janus kinase/signal Transducer and Activator of Transcription (JAK/STAT), Phosphoinositide 3-kinase/Protein Kinase B (PI3K/AKT), Vascular Endothelial Growth Factor and Phosphatase and Tensin Homolog (PTEN). Recently therapy that targets the MAPK signaling (BRAF/MEK inhibitors) and immunotherapy (anti-CTLA4 and anti-PD1 agents) have changed the therapeutic approaches to stage IV melanoma. In contrast, there are no solid data about patients with brain metastases, who are usually excluded from clinical trials. Retrospective data showed that BRAF-inhibitors, alone or in combination with MEK-inhibitors have interesting clinical activity in this setting. Prospective data about the combinations of BRAF/MEK inhibitors have been recently published, showing an improved overall response rate. Short intracranial disease control is still a challenge. Several attempts have been made in order to improve it with combinations between local and systemic therapies. Immunotherapy approaches seem to retain promising activity in the treatment of melanoma brain metastasis as showed by the results of clinical trials investigating the combination of anti-CTL4 (Ipilimumab) and anti-PD1(Nivolumab). Studies about the combination or the sequential approach of target therapy and immunotherapy are ongoing, with immature results. Several clinical trials are ongoing trying to explore new approaches in order to overcome tumor resistance. At this moment the correct therapeutic choices for melanoma with intracranial involvement is still a challenge and new strategies are needed.

Outcomes of BRAF V600E Pediatric Gliomas Treated With Targeted BRAF Inhibition

PURPOSE

Children with pediatric gliomas harboring a BRAF V600E mutation have poor outcomes with current chemoradiotherapy strategies. Our aim was to study the role of targeted BRAF inhibition in these tumors.

PATIENTS AND METHODS

We collected clinical, imaging, molecular, and outcome information from patients with BRAF V600E-mutated glioma treated with BRAF inhibition across 29 centers from multiple countries.

RESULTS

Sixty-seven patients were treated with BRAF inhibition (pediatric low-grade gliomas [PLGGs], n = 56; pediatric high-grade gliomas [PHGGs], n = 11) for up to 5.6 years. Objective responses were observed in 80% of PLGGs, compared with 28% observed with conventional chemotherapy (P < .001). These responses were rapid (median, 4 months) and sustained in 86% of tumors up to 5 years while receiving therapy. After discontinuation of BRAF inhibition, 76.5% (13 of 17) of patients with PLGG experienced rapid progression (median, 2.3 months). However, upon rechallenge with BRAF inhibition, 90% achieved an objective response. Poor prognostic factors in conventional therapies, such as concomitant homozygous deletion of CDKN2A, were not associated with lack of response to BRAF inhibition. In contrast, only 36% of those with PHGG responded to BRAF inhibition, with all but one tumor progressing within 18 months. In PLGG, responses translated to 3-year progression-free survival of 49.6% (95% CI, 35.3% to 69.5%) versus 29.8% (95% CI, 20% to 44.4%) for BRAF inhibition versus chemotherapy, respectively (P = .02).

CONCLUSION

Use of BRAF inhibition results in robust and durable responses in BRAF V600E-mutated PLGG. Prospective studies are required to determine long-term survival and functional outcomes with BRAF inhibitor therapy in childhood gliomas.

Celecoxib Prevents Doxorubicin-Induced Multidrug Resistance in Canine and Mouse Lymphoma Cell Lines

Background: Treatment of malignancies is still a major challenge in human and canine cancer, mostly due to the emergence of multidrug resistance (MDR). One of the main contributors of MDR is the overexpression P-glycoprotein (Pgp), which recognizes and extrudes various chemotherapeutics from cancer cells. Methods: To study mechanisms underlying the development of drug resistance, we established an in vitro treatment protocol to rapidly induce Pgp-mediated MDR in cancer cells. Based on a clinical observation showing that a 33-day-long, unplanned drug holiday can reverse the MDR phenotype of a canine diffuse large B-cell lymphoma patient, our aim was to use the established assay to prevent the emergence of drug resistance in the early stages of treatment. Results: We showed that an in vitro drug holiday results in the decrease of Pgp expression in MDR cell lines. Surprisingly, celecoxib, a known COX-2 inhibitor, prevented the emergence of drug-induced MDR in murine and canine lymphoma cell lines. Conclusions: Our findings suggest that celecoxib could significantly improve the efficiency of chemotherapy by preventing the development of MDR in B-cell lymphoma.

Small molecules, big impact: 20 years of targeted therapy in oncology

The identification of molecular targets and the growing knowledge of their cellular functions have led to the development of small molecule inhibitors as a major therapeutic class for cancer treatment. Both multitargeted and highly selective kinase inhibitors are used for the treatment of advanced treatment-resistant cancers, and many have also achieved regulatory approval for early clinical settings as adjuvant therapies or as first-line options for recurrent or metastatic disease. Lessons learned from the development of these agents can accelerate the development of next-generation inhibitors to optimise the therapeutic index, overcome drug resistance, and establish combination therapies. The future of small molecule inhibitors is promising as there is the potential to investigate novel difficult-to-drug targets, to apply predictive non-clinical models to select promising drug candidates for human evaluation, and to use dynamic clinical trial interventions with liquid biopsies to deliver precision medicine.

The "ART" of Epigenetics in Melanoma: From histone "Alterations, to Resistance and Therapies"

Malignant melanoma is the most deadly form of skin cancer. It originates from melanocytic cells and can also arise at other body sites. Early diagnosis and appropriate medical care offer excellent prognosis with up to 5-year survival rate in more than 95% of all patients. However, long-term survival rate for metastatic melanoma patients remains at only 5%. Indeed, malignant melanoma is known for its notorious resistance to most current therapies and is characterized by both genetic and epigenetic alterations. In cutaneous melanoma (CM), genetic alterations have been implicated in drug resistance, yet the main cause of this resistance seems to be non-genetic in nature with a change in transcription programs within cell subpopulations. This change can adapt and escape targeted therapy and immunotherapy cytotoxic effects favoring relapse. Because they are reversible in nature, epigenetic changes are a growing focus in cancer research aiming to prevent or revert the drug resistance with current therapies. As such, the field of epigenetic therapeutics is among the most active area of preclinical and clinical research with effects of many classes of epigenetic drugs being investigated. Here, we review the multiplicity of epigenetic alterations, mainly histone alterations and chromatin remodeling in both cutaneous and uveal melanomas, opening opportunities for further research in the field and providing clues to specifically control these modifications. We also discuss how epigenetic dysregulations may be exploited to achieve clinical benefits for the patients, the limitations of these therapies, and recent data exploring this potential through combinatorial epigenetic and traditional therapeutic approaches.