Metastatic Merkel Cell Carcinoma Research Articles

Durability of response to immune checkpoint inhibitors (ICI) in metastatic Merkel cell carcinoma (mMCC) after treatment cessation.

9543 Background: mMCC is a rare, aggressive neuroendocrine cancer which often occurs in older patients (pts) with multiple comorbidities. While initial response rates to ICI are high, optimal treatment duration, durability of response after treatment cessation and response to retreatment with ICI is unknown. Methods: mMCC pts from 12 international centres who received at least one dose of ICI and subsequently stopped treatment without progression for a minimum of 12 weeks were studied. Demographics, disease characteristics and treatment course were examined. Results: 40 pts with mMCC were included. Pt characteristics are summarised in Table. Median time on treatment was 13.5 months (range 1 to 35). Median time to best response was 4.5 months (range 1 to 17) and median time receiving treatment after best response was 8 months (range 0 to 29). 25 pts (63%) stopped primarily due to being in a complete or partial response (CR or PR), 9 (23%) due to toxicity and 6 (15%) due to other reasons, primarily pt choice or comorbidities. At time of discontinuation, 30 pts (75%) were in a CR, 8 (20%) in a PR and 2 pts (5%) had stable disease (SD). After a median follow up of 12 months from discontinuation, 14 pts (35%) have progressed (PD); 5 (36%) at a previous site, 5 (36%) at a new site and 4 (29%) at both. PD occurred after a median of 5.5 months (range 4 to 29) off treatment. 4 pts (29%) had a CNS recurrence, none of whom previously had CNS involvement. Pts in CR at time of discontinuation were less likely to progress (CR: 26% PD vs non-CR: 67% PD, p=0.044), but still had a considerable rate of PD (CR: 26%, PR: 57%, SD: 100%). Those who progressed had numerically less cycles of ICI prior to treatment cessation (17 vs 32, p>0.05). Baseline disease factors, time to best response and duration of treatment after best response were not associated with PD. ICI was restarted in 8 of 14 pts (57%) with PD, with response rate to retreatment of 75% (4 CR, 2 PR, 1 SD, 1 PD – pt with leptomeningeal disease). Median time to best response at retreatment was 3 months (range 2 to 7), with all responses ongoing after a median of 10 months back on treatment. 3 pts had an isolated site of PD successfully treated with radiation therapy and remain in remission off ICI. Conclusions: ICI responses in mMCC do not appear as durable off treatment as in other cancers, including in patients who achieve a CR. Ongoing treatment should be considered, though initial data on response to retreatment is promising.[Table: see text]

Avelumab in patients with previously treated Merkel cell carcinoma (JAVELIN Merkel 200): Updated overall survival data after more than five years of follow up.

9517 Background: Merkel cell carcinoma (MCC) is a rare and aggressive skin cancer. Although MCC is considered chemosensitive, patients typically have limited survival benefit with chemotherapy. Before the approval of immune checkpoint inhibitors, patients with metastatic MCC (mMCC) had a poor prognosis, with a historical 5-year overall survival (OS) rate of approximately 14%. Avelumab (anti–PD-L1) became the first approved treatment for patients with mMCC, based on efficacy and safety data observed in the phase 2 JAVELIN Merkel 200 trial (NCT02155647), in which patients with mMCC received avelumab monotherapy. We report the long-term OS data from the cohort of patients with mMCC whose disease had progressed after ≥1 prior line of chemotherapy. Methods: Eligible patients had histologically confirmed, measurable (per RECIST 1.1) stage IV MCC. Patients received avelumab 10 mg/kg by intravenous infusion every 2 weeks until confirmed disease progression, unacceptable toxicity, or withdrawal. Long-term OS was analyzed; updated data for other efficacy endpoints, including response and progression-free survival, were not obtained. Results: A total of 88 patients were enrolled and received avelumab treatment. As of September 25, 2020 (data cutoff), median follow-up was 65.1 months (range, 60.8-74.1 months). Median OS was 12.6 months (95% CI, 7.5-17.1 months); the 48- and 60-month OS rates were 30% (95% CI, 20%-40%) and 26% (95% CI, 17%-36%), respectively. At data cutoff, treatment was ongoing in 1 patient (1.1%) and an additional patient (1.1%) had reinitiated avelumab after previously discontinuing treatment. Reasons for treatment discontinuation were disease progression (n = 45 [51.1%]), adverse event (AE; n = 11 [12.5%]), death (n = 10 [11.4%]), withdrawal of consent (n = 9 [10.2%]), loss to follow-up (n = 1 [1.1%]), protocol noncompliance (n = 1 [1.1%]), and other reason (n = 10 [11.4%]). At data cutoff, 19 patients (21.6%) had discontinued treatment but remained in follow-up, and 63 patients (71.6%) had died; causes of death were disease progression (n = 49 [55.7%]), unknown reason (n = 9 [10.2%]), AE not related to study treatment (n = 3 [3.4%]), and other reason (n = 2 [2.3%]). In total, 26 patients (29.5%) received subsequent anticancer therapy; the most common subsequent therapies after trial discontinuation were avelumab (n = 4 [4.5%]), carboplatin and etoposide (n = 4 [4.5%]), and pembrolizumab (n = 4 [4.5%]). Conclusions: Avelumab monotherapy led to meaningful long-term OS in a subset of patients with mMCC whose disease had progressed after chemotherapy. These results further support the role of avelumab as a standard-of-care treatment for patients with mMCC. Clinical trial information: NCT02155647.

A cost-utility analysis of avelumab for metastatic Merkel cell carcinoma in Taiwan.

BackgroundMetastatic Merkel cell carcinoma (mMCC) has traditionally been managed with palliative chemotherapy regimens or best supportive care (BSC). Avelumab, a novel anti‐programmed death‐ligand 1 (PD‐L1) human monoclonal antibody for mMCC treatment, is being studied in the pivotal JAVELIN Merkel 200 trial.AimIncorporating trial results, this analysis aimed to evaluate the cost‐utility of avelumab in Taiwan.Methods and resultsA de novo partitioned‐survival model with three key health states related to survival (progression‐free disease, progressed disease, and death) was applied in this study. The data of clinical efficacy, safety, and patient utilities were obtained from the JAVELIN Merkel 200 trial, literature review, and Taiwanese clinical expert opinion. Cost‐utility analysis was performed, and results were presented as cost per quality‐adjusted life year (QALY) gained. For treatment‐naïve patients, the incremental cost‐effectiveness ratios (ICERs) for avelumab vs BSC and avelumab vs chemotherapy were US$44885.06 and US$42993.06 per QALY gained, respectively. As to treatment‐experienced mMCC patients, avelumab was associated with ICERs of US$27243.06 (vs BSC)/US$26557.43 (vs chemotherapy) per QALY gained. All ICERs remained consistently within the willingness‐to‐pay (WTP) threshold of US$53,333.33 per QALY gained.ConclusionThis study demonstrated avelumab to be a cost‐effective treatment option for both treatment‐experienced and treatment‐naïve mMCC patients with very poor prognosis in Taiwan.

Merkel Cell Polyomavirus Infection Induces an Antiviral Innate Immune Response in Human Dermal Fibroblasts.

Merkel cell polyomavirus (MCPyV) infects most of the human population asymptomatically, but in rare cases it leads to a highly aggressive skin cancer called Merkel cell carcinoma (MCC). MCC incidence is much higher in aging and immunocompromised populations. The epidemiology of MCC suggests that dysbiosis between the host immune response and the MCPyV infectious cycle could contribute to the development of MCPyV-associated MCC. Insufficient restriction of MCPyV by normal cellular processes, for example, could promote the incidental oncogenic MCPyV integration events and/or entry into the original cell of MCC. Progress toward understanding MCPyV biology has been hindered by its narrow cellular tropism. Our discovery that primary human dermal fibroblasts (HDFs) support MCPyV infection has made it possible to closely model cellular responses to different stages of the infectious cycle. The present study reveals that the onset of MCPyV replication and early gene expression induces an inflammatory cytokine and interferon-stimulated gene (ISG) response. The cGAS-STING pathway, in coordination with NF-κB, mediates induction of this innate immune gene expression program. Further, silencing of cGAS or NF-κB pathway factors led to elevated MCPyV replication. We also discovered that the PYHIN protein IFI16 localizes to MCPyV replication centers but does not contribute to the induction of ISGs. Instead, IFI16 upregulates inflammatory cytokines in response to MCPyV infection by an alternative mechanism. The work described herein establishes a foundation for exploring how changes to the skin microenvironment induced by aging or immunodeficiency might alter the fate of MCPyV and its host cell to encourage carcinogenesis. IMPORTANCE MCC has a high rate of mortality and an increasing incidence. Immune-checkpoint therapies have improved the prognosis of patients with metastatic MCC. Still, a significant proportion of the patients fail to respond to immune-checkpoint therapies or have a medical need for iatrogenic immune-suppression. A greater understanding of MCPyV biology could inform targeted therapies for MCPyV-associated MCC. Moreover, cellular events preceding MCC oncogenesis remain largely unknown. The present study aims to explore how MCPyV interfaces with innate immunity during its infectious cycle. We describe how MCPyV replication and/or transcription elicit an innate immune response via cGAS-STING, NF-κB, and IFI16. We also explore the effects of this response on MCPyV replication. Our findings illustrate how healthy cellular conditions may allow low-level infection that evades immune destruction until highly active replication is restricted by host responses. Conversely, pathological conditions could result in unbridled MCPyV replication that licenses MCC tumorigenesis.

491 Functional genomics screen identifies alternative targetable pathways for Merkel cell carcinoma

Merkel cell carcinoma (MCC) is a rare, aggressive neuroendocrine skin cancer. Most MCC tumors have Merkel cell polyomavirus integrated into the host genome (virus-positive MCC; VP-MCC), whereas virus-negative MCC (VN-MCC) tumors bear UV-induced mutations. Immune checkpoint inhibitors (ICI) are the first-line treatment for metastatic MCC, but the majority of patients are either not candidates for ICI or have disease progression while on treatment. In order to identify alternative therapeutic targets for these patients, we performed a druggable genome RNAi screen in MKL-2 (VP-MCC) and MCC26 (VN-MCC) cell lines. We screened >25,000 siRNA for their ability to reduce MCC viability at 72 hours. The main gene functions identified as essential to MCC viability included cell proliferation (VP- and VN-MCC) and apoptosis (VP-MCC). These results were corroborated by a follow-up RNAi screen including the two original cell lines, WaGa (VP-MCC), MCC13 (VN-MCC), and UISO (VN-MCC). Interestingly, many essential gene products identified in our screen were targets of compounds that selectively reduced MCC viability in an independent high-throughput MCC viability screen of ∼4000 small molecules. High-priority lead compounds supported by both screens showed efficacy in preclinical xenograft mouse models of MCC. Overall, our discovery and validation of novel targetable pathways have identified alternative treatment approaches for metastatic MCC.

Response durability after cessation of immune checkpoint inhibitors in patients with metastatic Merkel cell carcinoma: a retrospective multicenter DeCOG study

BackgroundImmune checkpoint inhibitors (ICI) have led to a prolongation of progression-free and overall survival in patients with metastatic Merkel cell carcinoma (MCC). However, immune-mediated adverse events due to ICI therapy are common and often lead to treatment discontinuation. The response duration after cessation of ICI treatment is unknown. Hence, this study aimed to investigate the time to relapse after discontinuation of ICI in MCC patients.MethodsWe analyzed 20 patients with metastatic MCC who have been retrospectively enrolled at eleven skin cancer centers in Germany. These patients have received ICI therapy and showed as best overall response (BOR) at least a stable disease (SD) upon ICI therapy. All patients have discontinued ICI therapy for other reasons than disease progression. Data on treatment duration, tumor response, treatment cessation, response durability, and tumor relapse were recorded.ResultsOverall, 12 of 20 patients (60%) with MCC relapsed after discontinuation of ICI. The median response durability was 10.0 months. Complete response (CR) as BOR to ICI-treatment was observed in six patients, partial response (PR) in eleven, and SD in three patients. Disease progression was less frequent in patients with CR (2/6 patients relapsed) as compared to patients with PR (7/11) and SD (3/3), albeit the effect of initial BOR on the response durability was below statistical significance. The median duration of ICI therapy was 10.0 months. Our results did not show a correlation between treatment duration and the risk of relapse after treatment withdrawal. Major reasons for discontinuation of ICI therapy were CR (20%), adverse events (35%), fatigue (20%), or patient decision (25%). Discontinuation of ICI due to adverse events resulted in progressive disease (PD) in 71% of patients regardless of the initial response. A re-induction of ICI was initiated in 8 patients upon tumor progression. We observed a renewed tumor response in 4 of these 8 patients. Notably, all 4 patients showed an initial BOR of at least PR.ConclusionOur results from this contemporary cohort of patients with metastatic MCC indicate that MCC patients are at higher risk of relapse after discontinuation of ICI as compared to melanoma patients. Notably, the risk of disease progression after discontinuation of ICI treatment is lower in patients with initial CR (33%) as compared to patients with initial PR (66%) or SD (100%). Upon tumor progression, re-induction of ICI is a feasible option. Our data suggest that the BOR to initial ICI therapy might be a potential predictive clinical marker for a successful re-induction.

Real-world clinical outcomes with first-lineavelumab in locally advanced/metastatic Merkel cell carcinoma in the USA: SPEAR-Merkel.

Aim: To assess clinical outcomes in patients with locally advanced (la) or metastatic (m) Merkel cell carcinoma (MCC) initiating first-line (1L) avelumab in a USA community oncology setting. Materials & methods: Adults with laMCC or mMCC initiating 1L avelumab were identified from The US Oncology Network electronic health record database and chart review. Results: Median overall survival and progression-free survival were not reached in laMCC (n=9) vs 20.2 and 10.0months in mMCC (n=19); response rates were similar (66.7% vs 63.2%). Conclusion: This is the first study to show clinical benefit in patients with laMCC receiving 1L avelumab in a USreal-world setting. Response rates in patients with mMCC were consistent with pivotal trials.

Suppressed Macrophage Responses in Metastatic Merkel Cell Carcinoma: Mining of Core Expression Features by Meta-Analytic Machine Learning (MAML)

Background: Merkel cell carcinoma (MCC) is an exceedingly lethal cutaneous neoplasm with highly controversial origin and a stiffly rising incidence. Immunotherapies, including checkpoint blockade (CPB), have shown some benefit in advanced-stage or chemotherapy-resistant MCC, but the performance has been at best erratic. The aim of the study was to establish the transcriptomic profiling of advanced MCC, as well as tumor infiltrating immune cell profiles using sophisticated the meta-analytic machine learning (MAML) method. Methods: Using an ML algorithm the authors trained our model to select consensus features that may be used to differentiate metastatic MCC from primary lesions. We then proceeded to validate and fine-tune the model’s performance with an assortment of probabilistic tools. Findings: We successfully extracted 98 core gene features for metastatic lesions with a superb accuracy, as shown by the AUROC of 0·905 (95% CI, 0·848-0.962) and AUPRC of 0·919 on leave-one-out cross validation. More significantly, our algorithm also identified core pathways with non-zero pathway dysregulation coefficients. The performance metrics for pathway analysis proved to be comparable to those for genes, with the AUROC of 0·888 (95% CI, 0·825, 0·950) and AUPRC of 0·842. Intriguingly, a significant reduction of monocyte-macrophage subpopulation was observed on cell enrichment-based immune profiling, a finding we substantiated through a deconvolution-based method. Interpretation: We have built a predictive model to find a reliable set of gene features in metastatic MCC, and successfully demonstrated both up- and down-regulated genes and pathways with non-zero coefficients, which provide a framework for new prospective targets in checkpoint blockade therapy. The excellent performance of the model points to the value and potential of MAML, an eclectic mixture of MA and predictive ML modelling. Funding Statement: This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (NRF-2019R1F1A1062023). Declaration of Interests: The authors declare no conflicts of interest regarding the contents of this article.

Clinical Outcomes, Costs, and Healthcare Resource Utilization in Patients with Metastatic Merkel Cell Carcinoma Treated with Immune Checkpoint Inhibitors vs Chemotherapy.

PurposeMerkel cell carcinoma (MCC) is a rare, aggressive skin cancer with poor prognosis. This study compared patient characteristics, comorbidities, adverse events (AEs), treatment persistence, healthcare resource utilization (HRU) and costs in patients with metastatic MCC (mMCC) treated with immune checkpoint inhibitors (ICIs) or recommended chemotherapy per 2018 National Comprehensive Cancer Network (NCCN) Guidelines.Patients and MethodsA retrospective, observational study was conducted using data from 3/1/2015 through 12/31/2017 from the Premier Healthcare Database, a US hospital discharge database. The study included patients aged ≥12 years with International Classification of Diseases Codes for MCC and metastasis, categorized by their first treatment (index) during the study period (ICI or NCCN-recommended chemotherapy [chemotherapy]). Patient, hospital, and visit characteristics were assessed at the index date and Charlson Comorbidity Index (CCI) score and comorbidities during a 6-month look-back period. Clinical outcomes, including AEs and treatment persistence were assessed over 90 days and HRU and costs over 180 days post-index.ResultsOf 75 patients with mMCC receiving ICIs (n=37) or chemotherapy (n=38), mean age was ≈73 years, and 21.3% had a history of immune-related (IR) conditions. Overall, ICI- and chemotherapy-treated patients were similar in most baseline characteristics, IR comorbidities, and CCI score. However, more ICI patients (46%) than chemotherapy patients (26%) persisted on treatment over 90-day follow-up, odds ratio (95% CI): 2.04 (0.93, 4.47), P=0.07. Over 180-day follow-up, 33% of patients had an inpatient admission with mean length of stay (LOS) ≈2 days shorter for ICI vs chemotherapy (not statistically significant). Total costs, primarily driven by pharmacy costs, were higher for ICIs than chemotherapy; other departmental costs were similar between treatment groups.ConclusionIn a real-world setting, patients with mMCC receiving ICIs had higher treatment persistence over 90 days, shorter inpatient LOS and similar departmental cost (excluding pharmacy cost) than those receiving chemotherapy.

Immunotherapy for Merkel cell carcinoma.

Merkel cell carcinoma (MCC) is an aggressive form of skin cancer which, while chemosensitive, has high rates of relapse and chemoresistance, limiting the impact of chemotherapy. An immunogenic tumor, the management of advanced MCC has changed dramatically with the introduction of checkpoint inhibitors. This review will focus on the impact of immunotherapy in unresectable and metastatic MCC, ongoing research in the adjuvant and neoadjuvant settings, and future directions of immune-based strategies for this challenging cancer.

Avelumab treatment in Italian patients with metastatic Merkel cell carcinoma: experience from an expanded access program

BackgroundThe incidence of Merkel cell carcinoma (MCC), a rare form of skin cancer with a poor prognosis, has increased in Italy in recent decades. Avelumab, an anti-programmed death ligand 1 monoclonal antibody, is approved for the treatment of metastatic MCC (mMCC) based on the results of the phase 2 JAVELIN Merkel 200 trial. The global avelumab expanded access program (EAP) was designed to provide compassionate use of avelumab prior to approval for patients with mMCC who had limited treatment options. We report findings from a subgroup of Italian patients enrolled in the avelumab EAP.MethodsEligible patients had mMCC and progressive disease following ≥ 1 prior line of chemotherapy or were ineligible for chemotherapy or clinical trial participation. Patients received avelumab 10 mg/kg intravenously every 2 weeks. Treating physicians were provided with an initial 3-month supply of avelumab; resupply was permitted if the patient achieved a complete response, partial response, stable disease, or other clinical benefit per physician assessment. Safety and efficacy data for the EAP were reported at the treating physician’s discretion.ResultsBetween April 1, 2016, and September 14, 2018, 109 requests for avelumab were received from Italy, and 102 were approved. All but 1 of the approved patients had received ≥ 1 prior line of therapy. At data cutoff (March 22, 2019), 95 patients had been supplied with avelumab and response data were available for 55 patients. The objective response rate in response-evaluable patients was 29.1%, including 6 patients (10.9%) who achieved a complete response and 10 patients (18.2%) who achieved a partial response; in the total population supplied with avelumab (n = 95), the proportion who had an objective response was 16.8%. The median duration of treatment in responding patients was 9.7 months (range, 3.5–41.7 months). The most frequently reported treatment-related adverse events were infusion-related reaction (single preferred term; n = 3 [3.2%]) and pyrexia (n = 2 [2.1%]).ConclusionsResults from Italian patients enrolled in the avelumab EAP are consistent with the findings of the JAVELIN Merkel 200 trial and confirm the efficacy and safety of avelumab treatment in this population.

Avelumab internalization by human circulating immune cells is mediated by both Fc gamma receptor and PD-L1 binding

ABSTRACT Avelumab is an IgG1 anti–programmed death ligand 1 (anti–PD-L1) monoclonal antibody that has been approved as a monotherapy for metastatic Merkel cell carcinoma and advanced urothelial carcinoma, and in combination with axitinib for advanced renal cell carcinoma. Avelumab is cleared faster and has a shorter half-life than other anti–PD-L1 antibodies, such as atezolizumab and durvalumab, but the mechanisms underlying these differences are unknown. IgG antibodies can be cleared through receptor-mediated endocytosis after binding of the antibody Fab region to target proteins, or via Fcγ receptor (FcγR)-mediated endocytosis. Unlike other approved anti–PD-L1 antibodies, avelumab has a native Fc region that retains FcγR binding capability. We hypothesized that the rapid clearance of avelumab might be due to the synergistic effect of both FcγR-mediated and PD-L1 target–mediated internalization. To investigate this, we performed in vitro and in vivo studies that compared engineered variants of avelumab and atezolizumab to determine mechanisms of cellular internalization. We found that both FcγR and PD-L1 binding contribute to avelumab internalization. While FcγR binding was the dominant mechanism of avelumab internalization in vitro, with CD64 acting as the most important FcγR, studies in mice and cynomolgus monkeys showed that both FcγR and PD-L1 contribute to avelumab elimination, with PD-L1 binding playing a greater role. These studies suggest that the rapid internalization of avelumab might be due to simultaneous binding of both PD-L1 and FcγR in trans. Our findings also provide a basis to alter the clearance and half-life of monoclonal antibodies in therapeutic development.

PCN60 Cost-Effectiveness of Avelumab in the Treatment of Patients with Metastatic Merkel Cell Carcinoma in Portugal

PCN60 Cost-Effectiveness of Avelumab in the Treatment of Patients with Metastatic Merkel Cell Carcinoma in Portugal

Folate hydrolase-1 (FOLH1) is a novel target for antibody-based brachytherapy in Merkel cell carcinoma.

BackgroundsFolate Hydrolase‐1 (FOLH1; PSMA) is a type II transmembrane protein, luminally expressed by solid tumour neo‐vasculature. Monoclonal antibody (mAb), J591, is a vehicle for mAb‐based brachytherapy in FOLH1+ cancers. Brachytherapy is a form of radiotherapy that involves placing a radioactive material a short distance from the target tissue (e.g., on the skin or internally); brachytherapy is commonly accomplished with the use of catheters, needles, metal seeds and antibody or small peptide conjugates. Herein, FOLH1 expression in primary (p) and metastatic (m) Merkel cell carcinoma (MCC) is characterized to determine its targeting potential for J591‐brachytherapy.Materials & MethodsParaffin sections from pMCC and mMCC were evaluated by immunohistochemistry for FOLH1. Monte Carlo simulation was performed using the physical properties of conjugated radioisotope lutetium‐177. Kaplan–Meier survival curves were calculated based on patient outcome data and FOLH1 expression.ResultsEighty‐one MCC tumours were evaluated. 67% (54/81) of all cases, 77% (24/31) pMCC and 60% (30/50) mMCC tumours were FOLH1+. Monte Carlo simulation showed highly localized ionizing tracks of electrons emitted from the targeted neo‐vessel. 42% (34/81) of patients with FOLH1+/− MCC had available survival data for analysis. No significant differences in our limited data set were detected based on FOLH1 status (p = 0.4718; p = 0.6470), staining intensity score (p = 0.6966; p = 0.9841) or by grouping staining intensity scores (− and + vs. ++, +++, +++) (p = 0.8022; p = 0.8496) for MCC‐specific survival or recurrence free survival, respectively.ConclusionsWe report the first evidence of prevalent FOLH1 expression within MCC‐associated neo‐vessels, in 60‐77% of patients in a large MCC cohort. Given this data, and the need for alternatives to immune therapies it is appropriate to explore the safety and efficacy of FOLH1‐targeted brachytherapy for MCC. What's already known about this topic? We report the first evidence of prevalent folate hydrolase‐1 (FOLH1; also known as prostate‐specific membrane antigen) expression within MCC‐associated neovessels. What does this study add? Herein, FOLH1 expression in Merkel cell carcinoma neovasculature is validated, and the therapeutic mechanism of specific, systemic targeting of disseminated disease with antibody‐based brachytherapy, is defined.

Pembrolizumab and other immune checkpoint inhibitors in locally advanced or metastatic Merkel Cell Carcinoma: safety and efficacy

ABSTRACT Introduction Merkel Cell Carcinoma (MCC) is a rare aggressive skin cancer, mostly affecting elderly patients. Until recently, patients with advanced disease were treated with cytotoxic chemotherapies despite rapid chemoresistance and high toxicity. As with other cancers, immune checkpoint inhibitors (CPI), including pembrolizumab, allow durable responses with a manageable safety profile in these patients. Areas covered This review describes the rationale for using PD-1/PD-L1 inhibitors in MCC, as well as efficacy and safety results from the three open-label trials investigating pembrolizumab or other PD-1/PD-L1 inhibitors in patients with advanced MCC. Real-life experience and predictive pre-treatment biomarkers are discussed to assess which patients are likely to be candidates for such strategies. Ongoing fields of research include the use of CPI in the adjuvant or neoadjuvant setting and combined strategies in refractory patients. Expert Opinion: CPI have become the standard of care for frontline treatment in patients with advanced MCC. Earlier introduction of CPI in the disease course, including neo-adjuvant and adjuvant settings, is likely to improve the outcomes further. Given the rarity of this cancer, we still need to harmonize efforts in order to conduct large-scale trials and efficiently identify best optimal care.

The risk of sudden cardiac death or ventricular arrhythmias on Immune checkpoint Inhibitors

Abstract Background Immune checkpoint inhibitors (ICI) have significantly improved the prognosis of many advanced cancers, and may be given in non-metastatic cancer in the near future. ICI have recently been reported to induce fulminant cardiotoxic effects such as myocarditis, responsible for ∼50% mortality rates. Objective To estimate the risk of sudden death (SD) and ventricular arrhythmias in patients receiving ICI using the World Health Organization individual case safety report (ICSR) database, Vigibase (WHO international pharmacovigilance database). Methods The system organ class MEDRA was used to identify cases as ICSR with the terms sudden death, sudden cardiac death, cardiac arrest, ventricular fibrillation, ventricular tachycardia, ventricular arrhythmia and torsades de pointes (named as SD events) from Nov 1967 to Nov 2019. We used the ATC code L01 which regroups 219 antineoplastic agents including ICI avelumab (anti-PDL1), ipilimumab (anti CTLA4), nivolumab (anti-PD1) and pembrolizumab (anti-PD1). A disproportionality analysis was performed to estimate of relative Odds Ratio (ROR). Signals were considered significant when the lower boundary of the 99.97% confidence interval (ROR0.25) was ≥1. Results We found that avelumab was significantly associated with SD events (ROR0.25=1.7). This overreporting was not observed for other ICIs. Avelumab was associated with 12 cases of cardiac arrest (n=11) or sudden death (n=1), which were reported since 2017 as the drug became available. There were however no signals regarding other terms including ventricular arrhythmias. Conclusions In spite of the potential severity of ICI-myocarditis, ICI do not appear as associated with the occurrence of sudden death or life-threatening arrhythmias, with the exception of avelumab (anti-PDL1), one of the latest developed ICI, indicated in metastatic Merkel cell carcinoma and advanced renal cell carcinoma. Further attention is warranted to confirm this signal that may vary among ICI therapies. Funding Acknowledgement Type of funding source: None

Real-world clinical outcomes in avelumab-treated patients (pts) in the United States (U.S.) from SPEAR-Merkel: Study informing treatment pathway decisions in Merkel cell carcinoma (MCC).

269 Background: MCC is a rare, aggressive disease associated with poor prognosis. Avelumab, a fully human anti–PD-L1 monoclonal antibody, was the first immune checkpoint inhibitor approved by the FDA for the treatment of metastatic MCC (mMCC). In the JAVELIN Merkel 200 trial (Clinical trial information: NCT02155647), avelumab resulted in durable responses and a high objective response rate (ORR) in pts with mMCC. This retrospective descriptive study assessed real-world clinical outcomes in avelumab-treated pts with locally advanced MCC (laMCC) and mMCC in a US community oncology setting. Methods: This study included data on avelumab-treated laMCC and mMCC pts from 1/1/17 to 3/31/19 within The US Oncology Network. Study data were captured through 9/30/19 using structured fields and chart review of iKnowMed electronic healthcare records. Real-world ORR was assessed. Duration of response (DOR), progression-free survival (PFS), and overall survival (OS) were estimated using the Kaplan-Meier method. Results: 33 pts initiated treatment with avelumab (laMCC n = 11; mMCC n = 22) and were followed up for a median of 10.9 months (range, 0.5-27.2 months). Median age was 77 years (range, 44-90+ years), 78.8% of pts were male, and the majority (84.8%) of pts were treated in the first-line setting. During treatment, 27.2% of pts had emergency department visits and 39.4% were hospitalized; 1% and 23.1%, respectively, were treatment related. Clinical outcomes are reported in the table. Conclusions: This is the first study to examine pts with laMCC treated with avelumab in a real-world setting. Although the sample population is small, results suggest the clinical benefits in the real world in pts with mMCC treated with avelumab are consistent with benefits reported in the JAVELIN Merkel 200 trial. [Table: see text]

Positron Emission Tomography in Merkel Cell Carcinoma.

Simple SummaryThere is currently no consensus on a widely accepted algorithm for imaging Merkel cell carcinoma (MCC) patients. Baseline, tomographic imaging is not generally recommended in early-stage disease, but its value in locally advanced and/or distant metastatic MCC has been well established. In this context, the hybrid imaging modality positron emission tomography/computed tomography (PET/CT) is increasingly applied in the workup of metastatic or unresectable MCC, providing essential information for staging, restaging, and treatment monitoring of the disease. Although the role of PET/CT in the management of loco-regional MCC is still limited and less well-defined, current evidence suggests its important contribution also in cases of localized MCC. Herein, we provide a structured literature review summarizing the most important studies on the role of PET or PET/CT with different radiopharmaceuticals in the clinical care of MCC.Merkel cell carcinoma (MCC) is a rare neuroendocrine skin malignancy usually arising as a nonspecific nodule on sun-exposed areas of the head and neck. Given the poor prognosis of this aggressive tumor, assessment of disease burden in pre- and post-treatment care may ensure an optimal management with significant implications for patient surveillance and prognosis. Although imaging has established its role in locally advanced or distant metastatic MCC, a standard imaging algorithm is yet to be determined and respective recommendations are mainly based on melanoma. Positron emission tomography/computed tomography (PET/CT) is increasingly evolving as a valuable imaging tool in metastatic or unresectable MCC, mostly utilizing the glucose analogue 18F-fluorodeoxyglucose (18F-FDG) as a radiotracer. Despite being inferior in detecting the disease in its early stages compared to the “gold standard” of sentinel lymph node biopsy, recent evidence suggests an important role for 18F-FDG PET/CT in the routine workup of localized MCC. Moreover, 68Ga-labeled somatostatin analogues have been employed as PET tracers in the field of MCC with promising, yet comparable to 18F-FDG, results. This article provides a structured literature review of the most important studies investigating the role of PET or PET/CT in the clinical practice of MCC.

Clinical, FDG-PET and molecular markers of immune checkpoint inhibitor response in patients with metastatic Merkel cell carcinoma

BackgroundMetastatic Merkel cell carcinoma (mMCC) is an aggressive neuroendocrine malignancy of the skin with a poor prognosis. Immune checkpoint inhibitors (ICIs) have shown substantial efficacy and favorable safety in clinical...

Merkel Cell Polyomavirus Small Tumor Antigen Activates Matrix Metallopeptidase-9 Gene Expression for Cell Migration and Invasion.

Merkel cell polyomavirus (MCV) small T antigen (sT) is the main oncoprotein for the development of Merkel cell carcinoma (MCC). MCC is a rare, clinically aggressive neuroendocrine tumor of the skin with a high propensity for local, regional, and distant spread. The dysregulation of matrix metalloproteinase-9 (MMP-9) has been implicated in multiple essential roles in the development of various malignant tumor cell invasion and metastasis. Previously, MCV sT was shown to induce the migratory and invasive phenotype of MCC cells through the transcriptional activation of the sheddase molecule, ADAM 10 (A disintegrin and metalloprotease domain-containing protein 10). In this study, we show that MCV sT protein stimulates differential expression of epithelial-mesenchymal transition (EMT)-associated genes, including MMP-9 and Snail. This effect is dependent on the presence of the large T stabilization domain (LSD), which is known to be responsible for cell transformation through targeting of promiscuous E3 ligases, including FBW7, a known MMP-9 and Snail regulator. Chemical treatments of MMP-9 markedly inhibited MCV sT-induced cell migration and invasion. These results suggest that MCV sT contributes to the activation of MMP-9 as a result of FBW7 targeting and increases the invasive potential of cells, which can be used for targeted therapeutic intervention.IMPORTANCE Merkel cell carcinoma (MCC) is the most aggressive cutaneous tumor without clearly defined treatment. Although MCC has a high propensity for metastasis, little is known about the underlying mechanisms that drive MCC invasion and metastatic progression. MMP-9 has been shown to play a detrimental role in many metastatic human cancers, including melanoma and other nonmelanoma skin cancers. Our study shows that MCV sT-mediated MMP-9 activation is driven through the LSD, a known E3 ligase-targeting domain, in MCC. MMP-9 may serve as the biochemical culprit to target and develop a novel approach for the treatment of metastatic MCC.