Toripalimab-Induced Dermatomyositis in a Patient with Metastatic Melanoma

Investigating the disparities among drug categories in drug-induced dermatomyositis: A systematic review

Drug-induced dermatomyositis (DIDM) is a rare and underestimated variant of dermatomyositis (DM) characterized by muscle damage and skin rash and related to certain drug exposure. The spectrum of drugs causing DIDM has evolved over time, originally implicating hydroxyurea, penicillamine, and statins as causative agents. Tumor necrosis factor α inhibitors and immune checkpoint inhibitors have also been associated with such conditions. To bridge the gap between current literature and clinical practice, and therefore guide clinicians, we conducted a comprehensive review of English literature from Pubmed, EMBASE, and MEDLINE. Our analysis included demographic data, clinical features, laboratory findings, therapeutic outcomes, and extant research pertaining to the probable pathogenesis of DIDM induced by various drugs. Furthermore, we categorized the drugs involved in DIDM cases into biologics and traditional agents for subsequent statistical analysis. Over time, there has been a gradual accumulation of reported DIDM cases. A total of 69 published DIDM cases were documented in our study, among which 33 should be attributed to biologics and the remaining 36 to traditional drugs. Interestingly, 41 of all DIDM cases had a previous history of malignancies. Additionally, DIDM cases exhibited similar cutaneous and muscular manifestations to classic DM, with the exception of cases induced by hydroxyurea, which did not entail muscle damage. Positive antinuclear antibodies and anti-TIF1-γ autoantibodies have been predominantly observed in biologics-induced cases, while positive anti-TIF1-γ antibodies were merely reported in the cases that were primarily diagnosed with malignant diseases and exposed to ICIs afterwards. Anti-TIF1-γ antibodies may potentially serve as a red flag in the identification of co-existing malignant diseases in DM patients. We also provided a comprehensive summary and exploration of potential mechanisms lying behind drug-induced dermatomyositis. In conclusion, our review consolidates the current literature on DIDM, highlighting the evolving spectrum of medications and elucidating the differences in clinical manifestations, laboratory findings, and underlying mechanisms.

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.

Dermatomyositis unleashed by immune checkpoint inhibitors. Three additional cases and a review of the literature

OBJECTIVES

Immune checkpoint inhibitors (ICI) have revolutionized the treatment of several locally advanced and metastatic tumors. They enhance the effector function of the immune system, consequently leading to different immune-related adverse events. The aim of the present study was to describe three cases of dermatomyositis (DM) triggered by ICI diagnosed at our institution and to perform a review of the literature.

METHODS

We performed a retrospective clinical, laboratory, and pathological evaluation of three cases of DM triggered by ICI belonging to a cohort of 187 DM patients from the Clinic Hospital Muscle Research Group of Barcelona from January 2009 to July 2022. Moreover, we undertook a narrative review of the literature from January 1990 to June 2022.

RESULTS

Cases from our institution were triggered by avelumab, an anti-PD-1 ligand (PD-L1), nivolumab, and pembrolizumab, both anti-programmed death-1 (PD-1). One of these patients had locally advanced melanoma, and two had urothelial carcinoma. The severity and response to treatment were heterogeneous among the different cases. All were positive at high titers for anti-TIF1γ autoantibodies; in one of them, serum before the onset of ICI was available, and anti-TIF1γ autoantibodies were already present. RNA expression of IFNB1, IFNG and genes stimulated by these cytokines were markedly elevated in these patients.

CONCLUSIONS

In conclusion, data from our patients and the narrative review suggest that early positivity to anti-TIF1γ unleashed by ICI may play a role in the development of full-blown DM, at least in some cases.

Environmental triggers of dermatomyositis: a narrative review

Dermatomyositis (DM) is an autoimmune disease that affects the skin, lungs, and muscle. Although the pathogenesis of DM is not completely understood, several environmental triggers have been linked to DM onset or flare. This article specifically examines the effects of herbal supplements, drugs, infections, ultraviolet (UV) radiation, and environmental pollutants on the onset or exacerbation of DM. Herbal supplements such as Spirulina platensis, Aphanizomenon flos-aquae, Chlorella, Echinacea, and Alfalfa have been implicated and are frequently used in health foods. Medications such as hydroxyurea, TNF-α inhibitors, immune checkpoint inhibitors (ICI), and penicillamine, as well as certain viral infections, such as parvovirus B19, coxsackie virus, polyomavirus, Epstein-Barr virus (EBV), hepatitis, influenza, and human immunodeficiency viruses (HIV) have been associated with DM onset. Bacterial infections and vaccinations have also been linked to the development of DM. Additional environmental factors, including UV radiation and air pollutants, such as silica, biological/mineral dust, and particulate air matter from vehicle and industrial emissions, may also play a role in DM pathogenesis. Overall, there is general agreement that an autoimmune attack of the skin, muscle, and lungs in DM can be triggered by various environmental factors and warrants further investigation.