Dermatomyositis Flare With Immune Checkpoint Inhibitor Therapy for Melanoma

Causes and Clinical Presentation of Drug-Induced Dermatomyositis: A Systematic Review

Importance

While several medications are known to induce dermatomyositis (DM), most existing studies are case reports or small case series from a single institution. There is also limited information on DM induced by immune checkpoint inhibitors, which are increasingly used in oncologic therapy.

Objective

To characterize causes and clinical presentation of drug-induced DM based on the current literature.

Evidence Review

A systematic review was performed in PubMed according to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guidelines, from inception to August 22, 2022. Articles meeting preestablished inclusion criteria (written in English and classified as original articles, case reports, literature reviews, and observation letters) were selected and data abstracted. Articles that met the scope of the review were also added from reference lists. When possible, study results were quantitatively combined.

Findings

In 134 studies (114 from the literature search and 20 additional studies pulled from reference lists) describing 165 cases, 88 patients (53.3%) were female, and the median (IQR) age was 61 (49-69) years. Among the cases of drug-induced DM, the most common associated medications were hydroxyurea (50 [30.3%]), immune checkpoint inhibitors (27 [16.4%]), statins (22 [13.3%]), penicillamine (10 [6.1%]), and tumor necrosis factor inhibitors (10 [6.1%]). Histopathologic testing, when undertaken, helped establish the diagnosis. There was a median (IQR) of 60 (21-288) days between drug initiation and drug-induced DM onset. History of cancer was reported in 85 cases (51.6%).

Conclusions and Relevance

In this systematic review, drug-induced DM was associated with multiple types of medications, including chemotherapies and immunotherapies. It is essential that dermatologists promptly recognize and diagnose drug-induced DM so that they can guide management to minimize interruption of therapy when possible.

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.

Immune-checkpoint inhibitor use in patients with cancer and pre-existing autoimmune diseases

Immune-checkpoint inhibitors (ICIs) have dramatically changed the management of advanced cancers. Designed to enhance the antitumour immune response, they can also cause off-target immune-related adverse events (irAEs), which are sometimes severe. Although the efficacy of ICIs suggests that they could have wide-ranging benefits, clinical trials of the drugs have so far excluded patients with pre-existing autoimmune disease. However, evidence is accumulating with regard to the use of ICIs in this 'at-risk' population, with retrospective data suggesting that they have an acceptable safety profile, but that there is a risk of disease flare or other irAE occurrence. The management of immunosuppressive drugs at ICI initiation in patients with autoimmune disease (or later in instances of disease flare or irAE) remains a question of particular interest in clinical practice, in which there is always a search for the balance between protecting against autoimmunity and ensuring a good tumour response. Although temporary use of immunosuppressants seems safe, prolonged use or use at ICI initiation might hamper the antitumour immune response, prompting clinicians to use the minimal efficient immunosuppressive regimen. However, a new paradigm is emerging, in which inhibitors of TNF or IL-6 could have synergistic effects with ICIs on tumour response, while also preventing severe irAEs. If confirmed, this 'decoupling' effect on toxicity and efficacy could change therapeutic practice in this field. Knowledge of the current use of ICIs in patients with pre-existing autoimmune disease, particularly with regard to the use of immunosuppressive drugs and/or biologic DMARDs, can help to guide clinical practice.

Cutaneous Adverse Events Associated with Immune Checkpoint Inhibitors: A Review Article

Immune checkpoint inhibitors (ICIs) have emerged as novel options that are effective in treating various cancers. They are monoclonal antibodies that target cytotoxic T-lymphocyte antigen 4 (CTLA-4), programmed cell death 1 (PD-1), and programmed cell death-ligand 1 (PD-L1). However, activation of the immune systems through ICIs may concomitantly trigger a constellation of immunologic symptoms and signs, termed immune-related adverse events (irAEs), with the skin being the most commonly involved organ. The dermatologic toxicities are observed in nearly half of the patients treated with ICIs, mainly in the form of maculopapular rash and pruritus. In the majority of cases, these cutaneous irAEs are self-limiting and manageable, and continuation of the ICIs is possible. This review provides an overview of variable ICI-mediated dermatologic reactions and describes the clinical and histopathologic presentation. Early and accurate diagnosis, recognition of severe toxicities, and appropriate management are key goals to achieve the most favorable outcomes and quality of life in cancer patients.