RARE DISEASE
Polymyositis
Polymyositis
Polymyositis
Drug discovery
6
drugs
With orphan designations
Overview
Polymyositis (PM) is a rare idiopathic inflammatory myopathy characterized by autoimmune-mediated skeletal muscle inflammation, leading to progressive symmetric proximal muscle weakness. Symptoms include difficulty climbing stairs, rising from seated positions, dysphagia, and fatigue. Systemic complications may involve interstitial lung disease, cardiomyopathy, or arthritis. Diagnosis requires clinical evaluation, elevated muscle enzymes (e.g., CK), electromyography, MRI, and muscle biopsy [1][5][13].
Population
Prevalence: 5–22 cases per 100,000 individuals globally, with peak incidence in adults aged 50–70 [2][4].
Gender: Female predominance (2:1 ratio), higher prevalence in African Americans [17][12].
Comorbidities: Associated with malignancies (e.g., lung, breast) and connective tissue diseases (e.g., lupus, scleroderma) [9][11].
Burden
Survival: 75% 5-year survival (PM) vs. 63% (dermatomyositis); median survival 11–12 years [2][4].
Complications: Respiratory failure, dysphagia-related aspiration, and malignancy-driven mortality [9][17].
Healthcare impact: High disability rates, prolonged immunosuppressive therapy, and frequent hospitalizations [9][19].
Therapies
First-line: High-dose corticosteroids (prednisone) ± steroid-sparing immunosuppressants (methotrexate, azathioprine) [3][8].
Refractory cases: Biologics (rituximab), IV immunoglobulin, or mycophenolate mofetil [3][18].
Supportive care: Physical therapy to preserve muscle function and multidisciplinary management for dysphagia/respiratory involvement [3][13].
Categories: rare neurological diseases, rare renal diseases, rare systemic and rheumatological diseases, rare transplant-related disorders
Research Papers
961 drug discovery papers about Polymyositis, with 2 first-in-class and 7 next-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
961 drug discovery papers about Polymyositis, with 2 first-in-class and 7 next-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
2026-08-10 | Outcomes of Immune Check Point Inhibitor Use in US Veterans With Pre-Existing Idiopathic Inflammatory Myopathies: Case Series and Literature Review.
Our objective was to identify and describe the clinical characteristics and outcomes in patients with pre-existing idiopathic inflammatory myopathies (IIMs) in the Veterans Health Administration (VHA) treated with immune checkpoint inhibitors (ICIs). All veterans receiving ICI infusions were identified. Patients with at least two International Classification of Disease codes for IIM before first ICI infusion underwent chart review to identify patients with confirmed IIM by American College of Rheumatology/EULAR criteria. The demographics, cancer diagnoses, laboratory findings, clinical course, and mortality rates were reported. IIM cases were also reviewed to determine if patients developed IIM flare following ICI treatment. We identified 29,539 veterans who received at least one ICI infusion in the VHA between June 6, 2011, and February 14, 2023. The eight patients with confirmed IIM before ICI treatment were mostly White men with an average age of 71.7 years at first ICI infusion. The IIM diagnoses were dermatomyositis in three patients, polymyositis in two, antisynthetase syndrome in two, and one rheumatoid arthritis (RA)/myositis overlap. Cancer diagnoses were lung (two), melanoma (two), head and neck (two), kidney/other urinary (one), and mesothelioma (one). Diagnosis of IIM was made on average 3.1 years before ICI treatment. One patient had an IIM flare after ICI. No IIM flares were identified in other patients. Our findings show that an IIM flare after ICI therapy can occur, but most patients did not develop a flare. These observations suggest ICIs can be considered as an option in patients with cancer with IIM with shared decision-making and close monitoring.
2026-08-08 | Pulmonary arterial hypertension in polymyositis: a case report
Pulmonary arterial hypertension (PAH) associated with connective tissue diseases is a lifethreatening condition in which elevated pressure in the pulmonary vasculature leads to a marked increase in right heart afterload, causing severe right ventricular failure and premature death. PAH is most frequently associated with systemic sclerosis and systemic lupus erythematosus. Polymyositis is a rare autoimmune disease resulting from aberrant activation of cytotoxic Tlymphocytes and macrophages against autologous muscle tissue, leading to inflammatory myopathy. In polymyositis, the inflammatory process may involve the vascular bed (small pulmonary artery vasculitis), which can lead to PAH. PAH in polymyositis is an extremely rare entity. This article presents a clinical observation of a patient with idiopathic polymyositis who developed a fatal complication — PAH — over several years. Key diagnostic aspects, clinical course features, and characteristic signs of the disease are demonstrated. The need for a multidisciplinary approach in managing patients with this condition is emphasised, and the importance of accumulating data on pulmonary hypertension in polymyositis is highlighted
2026-08-08 | A systematic review of abatacept and belatacept in immune-mediated diseases.
Abatacept (ABA) and belatacept (BEL) are immunomodulatory fusion proteins in which the extracellular domain of cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) is linked to the Fc fragment of human IgG1. Functionally, they bind to cell surface antigens CD80 and CD86 on antigen-presenting cells, thereby preventing CD28-mediated costimulatory signaling. This systematic review aims to evaluate the clinical efficacy of ABA and BEL in immune-mediated diseases, focusing on indications currently not approved by the United States Food and Drug Administration (FDA) or the European Medicines Agency (EMA). We searched PubMed and Web of Science for reports describing clinical efficacy of ABA or BEL in at least one patient with immune-mediated conditions outside FDA/EMA-approved indications. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist guided our data reporting. Of 5333 articles initially extracted, 2778 unique records were screened after de-duplication, and 96 matched our criteria and were included in this study. ABA was beneficial in patients diagnosed with Sjögren's syndrome (particularly secondary forms); autoimmunity in association with immunodeficiency; early, inflammatory and normal-like subtypes of systemic sclerosis; scleroderma; arthritis in systemic lupus erythematosus; inflammatory myopathies (polymyositis, immune-mediated necrotizing myositis, and antisynthetase syndrome); and giant-cell arteritis. Lower-level evidence studies reported positive results using ABA to treat granulomatosis with polyangiitis; relapsing polychondritis; sarcoidosis; and inflammatory eye diseases. Results of several studies highlighted the positive impact of ABA on arthritis in patients taking this drug for other indications. Likewise, several autoimmune diseases responded effectively to ABA when used to treat concomitant rheumatoid arthritis. Positive serological responses suggesting downstream modulation of B cell activation were reported in several randomized controlled trials. BEL was used after kidney transplantation in patients with proteinuric kidney disease or lupus nephritis, and in a few non-transplanted CTLA-4 haploinsufficiency carriers for immunodeficiency-associated autoimmunity. Our results provide a comprehensive summary of the efficacy of ABA and BEL across a broad spectrum of autoimmune diseases.
2026-08-06 | A Case Report on Polymyositis
Polymyositis is a chronic autoimmune inflammatory myopathy marked by symmetrical proximal muscle weakness due to immune-mediated muscle fiber damage.The disease predominantly affects adults, exhibiting a higher incidence in females, and is characterized by immune activation involving cytotoxic T lymphocytes and inflammatory mediators.Polymyositis symptoms include trouble getting up from a chair, climbing stairs, or lifting things. These symptoms are often accompanied by fatigue, muscle pain, trouble swallowing (dysphagia), and possible breathing problems. Patients exhibit progressive muscle weakness, dysphagia, and systemic manifestations which can severely affect quality of life.Diagnosis entails clinical assessment, laboratory analyses including elevated creatine kinase levels, autoantibody testing, imaging modalities, electromyography, and muscle biopsy for validation. The main goal of management is to make muscles stronger and improve functional outcomes through drug treatments. Corticosteroids are the first-line treatment, and immunosuppressive drugs like methotrexate and azathioprine are also used. .To improve the prognosis and the quality of life for patients, it is important to diagnose them early and use a multidisciplinary approach to treatment.
2026-07-13 | POLYMYOSITIS ASSOCIATED WITH PRIMARY BILIARY CIRRHOSIS AND OVARIAN CARCINOMA – CLINICAL CASE PRESENTATION AND LITERATURE REVIEW
Polymyositis is an idiopathic inflammatory myopathy classified under a heterogeneous group of autoimmune diseases predominantly presenting with symmetrical proximal muscle weakness, weakness of neck muscles with the manifestation of a "dropped head" symptom, dysphagia, dysphonia; elevated serum levels of creatine kinase (CK), sometimes in conjunction with elevated liver enzymes; characteristic EMG findings and muscle biopsy. The presence of myositis-specific antibodies in more than half of the patients facilitates the definition of distinct clinical subtypes and aids in accurate diagnosis, with an associated higher risk of involvement of other organs and systems such as the lungs, heart, liver, etc., most commonly presenting as interstitial pulmonary fibrosis, cardiomyopathy, and significantly less frequently primary biliary cirrhosis. A twofold increase in malignancies has been established compared to the general population, or the manifestation of myositis can be presented as a paraneoplastic syndrome. The first-line treatment method is the administration of intravenous corticosteroids in moderate or high doses combined with cytostatic therapy, with rare necessity for intravenous immunoglobulin administration, while plasmapheresis is considered an inapplicable method. We report a case of polymyositis with characteristic clinical and serological findings, with severe respiratory failure, developing twice in the absence of interstitial pulmonary fibrosis, primarily secondary myocardial damage during disease activity, and the presence of asymptomatic ovarian cancer and primary biliary cirrhosis discovered during the course of the disease, demonstrating the best therapeutic effectiveness from plasmapheresis. Accurate diagnosis relies on clinical, electrophysiological, and immunological findings, posing diagnostic challenges and questions that require the collaborative efforts of a multidisciplinary team.
2026-08-10 | Outcomes of Immune Check Point Inhibitor Use in US Veterans With Pre-Existing Idiopathic Inflammatory Myopathies: Case Series and Literature Review.
Our objective was to identify and describe the clinical characteristics and outcomes in patients with pre-existing idiopathic inflammatory myopathies (IIMs) in the Veterans Health Administration (VHA) treated with immune checkpoint inhibitors (ICIs). All veterans receiving ICI infusions were identified. Patients with at least two International Classification of Disease codes for IIM before first ICI infusion underwent chart review to identify patients with confirmed IIM by American College of Rheumatology/EULAR criteria. The demographics, cancer diagnoses, laboratory findings, clinical course, and mortality rates were reported. IIM cases were also reviewed to determine if patients developed IIM flare following ICI treatment. We identified 29,539 veterans who received at least one ICI infusion in the VHA between June 6, 2011, and February 14, 2023. The eight patients with confirmed IIM before ICI treatment were mostly White men with an average age of 71.7 years at first ICI infusion. The IIM diagnoses were dermatomyositis in three patients, polymyositis in two, antisynthetase syndrome in two, and one rheumatoid arthritis (RA)/myositis overlap. Cancer diagnoses were lung (two), melanoma (two), head and neck (two), kidney/other urinary (one), and mesothelioma (one). Diagnosis of IIM was made on average 3.1 years before ICI treatment. One patient had an IIM flare after ICI. No IIM flares were identified in other patients. Our findings show that an IIM flare after ICI therapy can occur, but most patients did not develop a flare. These observations suggest ICIs can be considered as an option in patients with cancer with IIM with shared decision-making and close monitoring.
2026-08-08 | Pulmonary arterial hypertension in polymyositis: a case report
Pulmonary arterial hypertension (PAH) associated with connective tissue diseases is a lifethreatening condition in which elevated pressure in the pulmonary vasculature leads to a marked increase in right heart afterload, causing severe right ventricular failure and premature death. PAH is most frequently associated with systemic sclerosis and systemic lupus erythematosus. Polymyositis is a rare autoimmune disease resulting from aberrant activation of cytotoxic Tlymphocytes and macrophages against autologous muscle tissue, leading to inflammatory myopathy. In polymyositis, the inflammatory process may involve the vascular bed (small pulmonary artery vasculitis), which can lead to PAH. PAH in polymyositis is an extremely rare entity. This article presents a clinical observation of a patient with idiopathic polymyositis who developed a fatal complication — PAH — over several years. Key diagnostic aspects, clinical course features, and characteristic signs of the disease are demonstrated. The need for a multidisciplinary approach in managing patients with this condition is emphasised, and the importance of accumulating data on pulmonary hypertension in polymyositis is highlighted
2026-08-08 | A systematic review of abatacept and belatacept in immune-mediated diseases.
Abatacept (ABA) and belatacept (BEL) are immunomodulatory fusion proteins in which the extracellular domain of cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) is linked to the Fc fragment of human IgG1. Functionally, they bind to cell surface antigens CD80 and CD86 on antigen-presenting cells, thereby preventing CD28-mediated costimulatory signaling. This systematic review aims to evaluate the clinical efficacy of ABA and BEL in immune-mediated diseases, focusing on indications currently not approved by the United States Food and Drug Administration (FDA) or the European Medicines Agency (EMA). We searched PubMed and Web of Science for reports describing clinical efficacy of ABA or BEL in at least one patient with immune-mediated conditions outside FDA/EMA-approved indications. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist guided our data reporting. Of 5333 articles initially extracted, 2778 unique records were screened after de-duplication, and 96 matched our criteria and were included in this study. ABA was beneficial in patients diagnosed with Sjögren's syndrome (particularly secondary forms); autoimmunity in association with immunodeficiency; early, inflammatory and normal-like subtypes of systemic sclerosis; scleroderma; arthritis in systemic lupus erythematosus; inflammatory myopathies (polymyositis, immune-mediated necrotizing myositis, and antisynthetase syndrome); and giant-cell arteritis. Lower-level evidence studies reported positive results using ABA to treat granulomatosis with polyangiitis; relapsing polychondritis; sarcoidosis; and inflammatory eye diseases. Results of several studies highlighted the positive impact of ABA on arthritis in patients taking this drug for other indications. Likewise, several autoimmune diseases responded effectively to ABA when used to treat concomitant rheumatoid arthritis. Positive serological responses suggesting downstream modulation of B cell activation were reported in several randomized controlled trials. BEL was used after kidney transplantation in patients with proteinuric kidney disease or lupus nephritis, and in a few non-transplanted CTLA-4 haploinsufficiency carriers for immunodeficiency-associated autoimmunity. Our results provide a comprehensive summary of the efficacy of ABA and BEL across a broad spectrum of autoimmune diseases.
2026-08-06 | A Case Report on Polymyositis
Polymyositis is a chronic autoimmune inflammatory myopathy marked by symmetrical proximal muscle weakness due to immune-mediated muscle fiber damage.The disease predominantly affects adults, exhibiting a higher incidence in females, and is characterized by immune activation involving cytotoxic T lymphocytes and inflammatory mediators.Polymyositis symptoms include trouble getting up from a chair, climbing stairs, or lifting things. These symptoms are often accompanied by fatigue, muscle pain, trouble swallowing (dysphagia), and possible breathing problems. Patients exhibit progressive muscle weakness, dysphagia, and systemic manifestations which can severely affect quality of life.Diagnosis entails clinical assessment, laboratory analyses including elevated creatine kinase levels, autoantibody testing, imaging modalities, electromyography, and muscle biopsy for validation. The main goal of management is to make muscles stronger and improve functional outcomes through drug treatments. Corticosteroids are the first-line treatment, and immunosuppressive drugs like methotrexate and azathioprine are also used. .To improve the prognosis and the quality of life for patients, it is important to diagnose them early and use a multidisciplinary approach to treatment.
2026-07-13 | POLYMYOSITIS ASSOCIATED WITH PRIMARY BILIARY CIRRHOSIS AND OVARIAN CARCINOMA – CLINICAL CASE PRESENTATION AND LITERATURE REVIEW
Polymyositis is an idiopathic inflammatory myopathy classified under a heterogeneous group of autoimmune diseases predominantly presenting with symmetrical proximal muscle weakness, weakness of neck muscles with the manifestation of a "dropped head" symptom, dysphagia, dysphonia; elevated serum levels of creatine kinase (CK), sometimes in conjunction with elevated liver enzymes; characteristic EMG findings and muscle biopsy. The presence of myositis-specific antibodies in more than half of the patients facilitates the definition of distinct clinical subtypes and aids in accurate diagnosis, with an associated higher risk of involvement of other organs and systems such as the lungs, heart, liver, etc., most commonly presenting as interstitial pulmonary fibrosis, cardiomyopathy, and significantly less frequently primary biliary cirrhosis. A twofold increase in malignancies has been established compared to the general population, or the manifestation of myositis can be presented as a paraneoplastic syndrome. The first-line treatment method is the administration of intravenous corticosteroids in moderate or high doses combined with cytostatic therapy, with rare necessity for intravenous immunoglobulin administration, while plasmapheresis is considered an inapplicable method. We report a case of polymyositis with characteristic clinical and serological findings, with severe respiratory failure, developing twice in the absence of interstitial pulmonary fibrosis, primarily secondary myocardial damage during disease activity, and the presence of asymptomatic ovarian cancer and primary biliary cirrhosis discovered during the course of the disease, demonstrating the best therapeutic effectiveness from plasmapheresis. Accurate diagnosis relies on clinical, electrophysiological, and immunological findings, posing diagnostic challenges and questions that require the collaborative efforts of a multidisciplinary team.
Access all drug discovery papers and probability of success in trials forecasts:
Access all drug discovery papers and probability of success in trials forecasts:
Drug Discovery Landscape
6 orphan drug designations for Polymyositis.
6 orphan drug designations for Polymyositis.
Drug | Therapy type | Regulator | Orphan designation | Approval | Sponsor |
|---|---|---|---|---|---|
Glucagon like peptide-1 (GLP-1) Elastin like peptide (ELP)-120 fusion protein | proteins | FDA | 2021-08-31 | — | ImmunoForge Co., Ltd. |
(2S,3R)-N-[(2S)-3-(cyclopent-1-en-1-yl)-1-[(2R)-2-methyloxiran-2-yl]-1-oxopropan-2-yl]-3-hydroxy-3-(4-methoxyphenyl)-2-[(2S)-2-[2-(morpholin-4-yl)acetamido]propanamido]propanamide maleate | small molecules | FDA | 2020-10-21 | — | Kezar Life Sciences, Inc. |
Siponimod [BAF312] | small molecules | EMA | 2014-11-19 | — | Novartis Europharm Limited |
Siponimod | small molecules | FDA | 2013-11-26 | — | Novartis Pharmaceuticals Corporation |
Human normal immunoglobulin [Gammagen] | antibodies | EMA | 2003-10-24 | — | [INACTIVE] Orfagen |
Immune globulin intravenous (human) | antibodies | FDA | 1992-10-13 | — | Immuno Clinical Research Corp. |
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