Metastatic Merkel cell carcinoma and myasthenia gravis: contraindication for therapy with immune checkpoint inhibitors?

Immune Checkpoint Inhibitors in Patients with Pre-existing Neurologic Autoimmune Disorders

PURPOSE OF REVIEW

The use of immune checkpoint inhibitors (ICIs) for oncologic indications is associated with immune-related adverse events (irAEs). Patients with pre-existing autoimmune diseases are at increased risk of irAEs and have largely been excluded from clinical trials of ICIs. Therefore, there is limited data on the safety of safety of ICIs in patients with pre-existing neurologic autoimmune diseases (nAIDs) such as myasthenia gravis and multiple sclerosis. This review aims to synthesize the literature on the post-marketing experience with ICI in patients with pre-existing nAID and to discuss possible strategies for mitigating the risk of post-ICI nAID relapses.

RECENT FINDINGS

Patients with pre-existing myasthenia gravis (MG), myositis, and paraneoplastic encephalitis appear highly susceptible to neurologic relapses of their underlying neurologic disorder following ICI initiation; these relapses can cause considerable morbidity and mortality. In patients with multiple sclerosis (MS), the risk and severity of MS relapses following ICI appears to be relatively lower compared to MG. Preliminary evidence suggests that older MS patients with no recent focal neuroinflammatory activity may be safely treated with ICI. Among the several case reports of ICI in patients with a history of Guillain-Barre syndrome (GBS), neurologic worsening was only recorded in one patient who was in the acute phase of GBS at the time of ICI start. Initiating an ICI in a patient with pre-existing nAID involves a complex risk-benefit discussion between the patient, their oncologist, and neurologist. Relevant issues to consider before ICI include the choice of disease-modifying therapy for nAID (if any) and strategies for promptly identifying and managing nAID relapses should they occur. Currently, the literature consists mainly of case reports and case series, subject to publication bias. Prospective studies of ICI in patients with nAID are needed to improve the level of evidence.

Review of Merkel cell carcinoma with solitary pancreatic metastases mimicking primary neuroendocrine tumor of the pancreas

OBJECTIVE/BACKGROUND

Merkel cell carcinoma (MCC) but metastases to the pancreas are very rare. There are only a few cases of isolated metastases of MCC to the pancreas. Because of this rarity, it can be wrongly diagnosed as a neuroendocrine tumor of the pancreas(pNET), especially the poorly differentiated neuroendocrine carcinoma (PNEC) subtype, in which the treatment is vastly different than that of MCC with isolated metastases of the pancreas.

METHODS

An electronic search of the PubMed and google scholar databases was performed to obtain the literature on MCC with pancreatic metastases, using the following search terms: Merkel cell carcinoma, pancreas, and metastases. Results are limited to the following available article types: case reports and case series. We identified 45 cases of MCC with pancreatic metastases from the PubMed and Google Scholar database search and examined their potential relevance. Only 22 cases with isolated pancreatic metastases were taken for review including one case that we encountered.

RESULTS

The results from our review of cases of isolated pancreatic metastases of MCC were compared to the characteristics of the poorly differentiated pancreatic neuroendocrine tumor (PNEC). We found the following: (a) MCC with isolated pancreatic metastases occurred at an older age than PNEC and with male gender predominance (b) Most of the metastases occurred within 2 years of initial diagnosis of MCC (c) Resection of pancreatic mass was the first line treatment in case of resectable PNECs whereas resection of metastases was infrequently performed in MCC with pancreatic metastases.

Outcome of patient with myasthenia gravis with the use of immunotherapy in metastatic Merkel cell carcinoma

We report on a 79-year-old man diagnosed with localized Merkel cell carcinoma (MCC) who also had acetylcholine receptor antibody (Ach-R-Ab)-positive myasthenia gravis (MG) controlled on prednisolone, mycophenolate and intravenous immunoglobulin (IVIG). His MCC was initially treated with radiation, followed by chemotherapy on metastatic recurrence. Chemotherapy initially stabilized the disease, but he experienced significant fatigue and his disease progressed within 3 months. After careful consideration of the risk of a myasthenic crisis, he was commenced on avelumab. He had initial partial response, though he ultimately developed progressive disease which led to a decision for best supportive care at 10 months post starting immunotherapy. Importantly, as per spirometry, his MG remained stable throughout immunotherapy. We present the current case to demonstrate that MG should not be viewed as an absolute contraindication to immunotherapy in scenarios where there are limited alternate therapeutic options.

A systematic comparison of hepatobiliary adverse drug reactions in FDA and EMA drug labeling reveals discrepancies

Drug labeling informs physicians and patients on the safe and effective use of medication. However, recent studies suggested discrepancies in labeling of the same drug between different regulatory agencies. Here, we evaluated the hepatic safety information in labeling for 549 medications approved by the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA). Limited discrepancies were found regarding risk for hepatic adverse drug reactions (ADRs) (8.7% in hepatic ADR warnings and 21.3% in contraindication for liver disease), while caution should be exercised over drugs with inconsistencies in contraindications for liver disease and evidence for hepatotoxicity (4.9%). Most discrepancies were attributable to less-severe hepatic events and low-frequency hepatic ADR reports and had limited implication on clinical outcomes.

Immunotherapy use outside clinical trial populations: never say never?

BACKGROUND

Based on favourable outcomes in clinical trials, immune checkpoint inhibitors (ICIs), most notably programmed cell death protein 1 (PD-1) and cytotoxic T-lymphocyte antigen-4 (CTLA-4) inhibitors, are now widely used across multiple cancer types. However, due to their strict inclusion and exclusion criteria, clinical studies often do not address challenges presented by non-trial populations.

DESIGN

This review summarises available data on the efficacy and safety of ICIs in trial-ineligible patients, including those with autoimmune disease, chronic viral infections, organ transplants, organ dysfunction, poor performance status, and brain metastases, as well as the elderly, children, and those who are pregnant. In addition, we review data concerning other real-world challenges with ICIs, including timing of therapy switch, relationships to radiotherapy or surgery, re-treatment after an immune-related toxicity, vaccinations in patients on ICIs, and current experience around ICI and coronavirus disease-19. Where possible, we provide recommendations to aid the often-difficult decision-making process in those settings.

CONCLUSIONS

Data suggest that ICIs are often active and have an acceptable safety profile in the populations described above, with the exception of PD-1 inhibitors in solid organ transplant recipients. Decisions about whether to treat with ICIs should be personalised and require multidisciplinary input and careful counselling of patients with respect to potential risks and benefits. Clinical judgements need to be carefully weighed, considering factors such as underlying cancer type, feasibility of alternative treatment options, or activity in trial-eligible patients.

Merkel Cell Carcinoma With Isolated Pancreatic Metastasis

Merkel cell carcinoma (MCC) is a highly aggressive cutaneous neuroendocrine carcinoma, frequently associated with distant metastasis. However, recurrence of MCC manifesting with only pancreatic involvement is exceedingly rare. A 53-year-old man presented to our institution with abdominal discomfort 3 months after initial resection of chest wall MCC. Imaging revealed lesions in the pancreas and peripancreatic lymph nodes. Pathology obtained through endoscopic ultrasound confirmed recurrence of MCC. He underwent chemotherapy with cisplatin and etoposide, resulting in a complete resolution of the pancreatic lesions. Unfortunately, he passed away from sudden cardiac arrest while being in remission from MCC. Immunohistochemistry is crucial in differentiating MCC from primary pancreatic glandular and neuroendocrine tumors. While there are no definitive guidelines in the management of pancreatic lesions associated with MCC, checkpoint inhibitor immunotherapy is increasingly being used.

The safety and efficacy of immune-checkpoint inhibitors in patients with cancer and pre-existing autoimmune diseases

Objective: This study aims at investigating the safety and efficacy of immune-checkpoint inhibitors (ICIs) in patients with cancer and pre-existing autoimmune disease (AID). Materials & methods: PubMed, Embase and Cochrane Library were searched for relevant studies. The primary end points of the study were immunotoxicity and cancer response. Results: At the early use of ICIs, compared with those with active AID, grade 3-4 AID flare occurred more frequently in patients with inactive AID after treatment with ICIs; and the incidence of grade 3-4 immunotoxic effects was significantly lower in patients undergoing immunosuppressive therapy than those without corresponding treatment. In addition, patients with worsening AID generally obtained a better objective response than those without a flare. Conclusion: This study demonstrates that the toxic effects induced by immunotherapy are generally manageable in patients with cancer and pre-existing AID, some of whom even achieve satisfactory antitumor effects in clinical practice.

Immune Checkpoint Inhibitor-Induced Myasthenia Gravis

The development of immune checkpoint inhibitors (ICIs) has been a major breakthrough in cancer immunotherapy. The increasing use of ICIs has led to the discovery of a broad spectrum of immune-related adverse events (irAEs). Immune-related myasthenia gravis (irMG) is a rare but life-threatening irAE. In this review, the clinical presentations of irMG are described and the risk of irMG-related mortality is examined using information from relevant studies. In 47 reported cases of irMG with clear causes of mortality, irMG appeared to be a distinct category of neuromuscular disorders and differed from classical MG in terms of its demographic patient characteristics, pathogenesis, serology profile, response to treatment, associated complications, and prognosis. Because of the high mortality of irMG, measures to increase the vigilance of medical teams are necessary to ensure the timely identification of the signs of irMG and early treatment, particularly in the early course of ICI therapy. The diagnostic plans should be comprehensive and include the evaluation of other organ systems, such as the dermatological, gastrointestinal, respiratory, neuromuscular, and cardiovascular systems, in addition to the traditional diagnostic tests for MG. Treatment plans should be individualized on the basis of the extent of organ involvement and clinical severity. Additional therapeutic studies on irMG in the future are required to minimize irAE-related mortality and increase the safety of patients with cancer in the ICI era.

Efficacy and Toxicity of Immune -Checkpoint Inhibitors in Patients With Preexisting Autoimmune Disorders

Immunotherapy is an important armamentarium for cancer treatment nowadays. Apart from their significant effectiveness in controlling disease they also generate potential severe immune related adverse effects. Preexistence of immune related conditions may eventually predispose to the development of more severe complication and extreme caution have been taken in treating these patients. We performed a literature review searching for case reports and case series in order to offer evidence-based data for clinical management of these patients. Preexisting serological-only immune abnormalities or presence of a predisposing genetic background does not seem to confer significant risk but existing data is scarce. Most patients with preexistent autoimmune diseases can probably treated with checkpoint inhibitors as they seem to have at least the same response rate as the general cancer population. Under treatment, a significant part of them (at least 30%) can experience a flare of their baseline disease which can sometime be severe. Life-threatening cases seems rare and disease flare can be generally managed with steroids. The volume of available data is more important for rheumatologic diseases than for inflammatory bowel diseases were more caution should be observed. However, it has to be kept in mind that new immune related adverse effects (IrAE) are seen with a similar frequency as the flare of the baseline disease. Both flare-up's and newly developed IrAE are generally manageable with a careful clinical follow-up and prompt therapy.

Immunotherapy in Underrepresented Populations of Patients with Cancer: Do We Have Enough Evidence at Present? A Focus on Patients with Major Viral Infections and Autoimmune Disorders

The safety and activity of immune checkpoint inhibitors have been characterized in interventional and observational studies. However, only small studies have specifically investigated these agents in patients who are excluded or underrepresented in clinical trials, frequently referred to as "special populations" or "underrepresented populations." These include older adults, those with dysregulated immune activation, patients with a compromised immune function, and those carrying major viral infections, lymphoproliferative diseases, and major organ dysfunctions. Therefore, there remains substantial uncertainty regarding the use of immune checkpoint inhibitors in these specific settings. The Network of Italian Supportive Care in Oncology has carried out a multidisciplinary project, with the contribution of oncologists and other specialists, to retrieve the existing evidence on the use of immunotherapy in patients with solid and hematological cancers with the final aim to provide an expert guidance. The results of this effort are presented in this article, which is focused on patients with major viral infections or those with immune dysregulation/autoimmune diseases, and could be useful to guide decisions in clinical practice and to design prospective clinical trials focusing on the use of immunotherapy in these populations. IMPLICATIONS FOR PRACTICE: Substantial uncertainty remains regarding the use of immune checkpoint inhibitors in "underrepresented" patients, such as older adults, those with dysregulated immune activation, and patients with a compromised immune function, major viral infections, lymphoproliferative diseases or major organ dysfunctions. The Network of Italian Supportive Care in Oncology has carried out a multidisciplinary project to retrieve the existing evidence on the use of immunotherapy in underrepresented patients with cancer in order provide an expert guidance. The results of this effort, with a focus on patients with major viral infections or those with immune dysregulation/autoimmune diseases, are presented in this article and could be useful to guide decisions both in clinical practice and to design clinical trials.