Idiopathic Inflammatory Myositis Market Set for Strong Growth at 16.8% CAGR Through 2036, Driven by Rising Demand for Targeted Therapies | DelveInsight

DelveInsight's report sizes the Idiopathic Inflammatory Myositis market at USD 714 million across the 7MM in 2025, with a significant 16.8% CAGR forecast through 2036. This growth is driven by the high unmet medical need, increasing disease awareness, advancements in diagnostic capabilities, and the growing focus on developing targeted therapies to address disease heterogeneity and improve patient outcomes. Additionally, the expanding clinical development pipeline, including Dazukibart (Pfizer), Nerandomilast (Boehringer Ingelheim), CABA-201 (Cabaletta Bio), Ulviprubart (ABC008; Abcuro), and other targeted treatment candidates, is expected to drive market growth across the 7MM from 2026–2036, with significant commercial opportunities as innovative therapies advance toward potential approval and launch.

New York, USA, Nov. 10, 2026 (GLOBE NEWSWIRE) -- Idiopathic Inflammatory Myositis Market Set for Strong Growth at 16.8% CAGR Through 2036, Driven by Rising Demand for Targeted Therapies | DelveInsight

DelveInsight's report sizes the Idiopathic Inflammatory Myositis market at USD 714 million across the 7MM in 2025, with a significant 16.8% CAGR forecast through 2036. This growth is driven by the high unmet medical need, increasing disease awareness, advancements in diagnostic capabilities, and the growing focus on developing targeted therapies to address disease heterogeneity and improve patient outcomes. Additionally, the expanding clinical development pipeline, including Dazukibart (Pfizer), Nerandomilast (Boehringer Ingelheim), CABA-201 (Cabaletta Bio), Ulviprubart (ABC008; Abcuro), and other targeted treatment candidates, is expected to drive market growth across the 7MM from 2026–2036, with significant commercial opportunities as innovative therapies advance toward potential approval and launch.

Recently published Idiopathic Inflammatory Myositis Market Insights report includes a comprehensive understanding of current treatment practices, idiopathic inflammatory myositis emerging drugs, market share of individual therapies, and current and forecasted market size from 2022 to 2036, segmented into leading markets [the United States, the EU4 (Germany, France, Italy, and Spain), the United Kingdom, and Japan]. 

Idiopathic Inflammatory Myositis Market Summary

• The market size for idiopathic inflammatory myositis was found to be USD 714 million in the 7MM in 2025.
• The United States accounted for about 55% of the 7MM market in 2025, the largest share of any market covered.
• The total number of diagnosed prevalent cases of IIM in the 7MM ranges approximately 198,000 cases in 2025. This growth is primarily driven by population aging, improved disease recognition, greater diagnostic awareness, and enhanced access to specialist care.
• Leading idiopathic inflammatory myositis companies, such as Pfizer, Boehringer Ingelheim, Cabaletta Bio, Abcuro, Amgen, Novartis Pharmaceuticals, Lakefront Biotherapeutics, Argenx, AstraZeneca, RESTEM, Gilead Sciences, and others, are developing new idiopathic inflammatory myositis treatment drugs that can be available in the idiopathic inflammatory myositis market in the coming years. 
• The promising idiopathic inflammatory myositis therapies in clinical trials include Dazukibart, Nerandomilast, CABA-201, Ulviprubart (ABC008), Daxdilimab, Rapcabtagene autoleucel, GLPG3667, Efgartigimod (VYVGART), Anifrolumab (SAPHNELO), RESTEM-L (ULSC), Gamgertamig (OM336), and others.

Download the free sample page to discover new treatments for idiopathic inflammatory myositis @ https://www.delveinsight.com/report-store/idiopathic-inflammatory-myositis-market

As per Aparna Thakur, Project Manager of Forecasting at DelveInsight, brepocitinib (LISRAYA) is expected to account for ~17% of the IIM market in 2036, supported by its first-in-class positioning as an oral targeted therapy for dermatomyositis, increasing physician familiarity with JAK/TYK2 inhibition, convenient once-daily oral administration, and the substantial unmet need for effective steroid-sparing treatment options in dermatomyositis.

Key Factors Driving the Growth of the Idiopathic Inflammatory Myositis Market 

• Rising Disease Awareness and Improved Diagnosis: Growing awareness of idiopathic inflammatory myositis (IIM), including dermatomyositis, polymyositis, and inclusion body myositis, is supporting earlier disease recognition. Advances in autoantibody testing, muscle imaging, and diagnostic techniques are helping improve disease identification and patient management.
• Increasing Adoption of Targeted Therapies: The limitations of conventional treatments, such as corticosteroids and immunosuppressants, are driving interest in targeted therapeutic approaches. Biologics and other immune-modulating agents offer opportunities to improve disease control, particularly among patients with refractory disease or inadequate responses to existing treatments.
• Expanding Clinical Development Pipeline: Ongoing research into novel mechanisms of action, including B-cell depletion, cytokine inhibition, and modulation of immune pathways, is strengthening the IIM drug development landscape. Clinical trials evaluating investigational therapies are expected to expand treatment options and support future market growth.
• Growing Investment in Rare Disease Research: Increasing investment by pharmaceutical and biotechnology companies in autoimmune and rare inflammatory diseases is supporting the development of novel IIM treatments. Orphan drug incentives, research collaborations, and advances in immunology are helping accelerate clinical development and potentially improve commercial opportunities.

Download the report to understand the top emerging idiopathic inflammatory myositis drugs @ Idiopathic Inflammatory Myositis Clinical Trials

Idiopathic Inflammatory Myositis Market Analysis

• Treatment of idiopathic inflammatory myopathies continues to rely primarily on corticosteroids and conventional immunosuppressants, including methotrexate, azathioprine, mycophenolate mofetil, and tacrolimus, which are widely used across dermatomyositis, polymyositis, and related subtypes. 
• However, inconsistent treatment responses, delayed therapeutic effects, disease relapse, and the cumulative toxicity associated with long-term corticosteroid and immunosuppressant use underscore the need for more effective steroid-sparing and subtype-specific treatment options.
• The approved IIM treatment landscape remains relatively limited, with intravenous immunoglobulin (IVIG) and conventional immunosuppressive therapies forming the mainstay of treatment. 
• OCTAGAM 10% (IVIG) represents an important approved therapeutic option for adults with dermatomyositis. 
• The emerging IIM pipeline is becoming increasingly diverse, with investigational and targeted therapies addressing multiple mechanisms of action and disease subtypes. 
• Notable candidates include nerandomilast, dazukibart, efgartigimod, anifrolumab (SAPHNELO), umbilical cord lining stem cells (ULSC), CABA-201, ulviprubart (ABC008), daxdilimab, and GLPG3667, reflecting ongoing efforts to expand treatment options and address unmet clinical needs across the IIM spectrum.

Idiopathic Inflammatory Myositis Competitive Landscape

Some of the IIM drugs under development include Dazukibart (Pfizer), Nerandomilast (Boehringer Ingelheim), CABA-201 (Cabaletta Bio), Ulviprubart (ABC008; Abcuro), Daxdilimab (Amgen), Rapcabtagene autoleucel (Novartis Pharmaceuticals), GLPG3667 (Lakefront Biotherapeutics), Efgartigimod (VYVGART; Argenx), Anifrolumab (SAPHNELO; AstraZeneca), RESTEM-L (ULSC; RESTEM), Gamgertamig (OM336; Gilead Sciences and Lakefront Biotherapeutics), and others.

Pfizer’s Dazukibart is an investigational monoclonal antibody targeting interferon-beta (IFN-β), being developed by Pfizer for idiopathic inflammatory myopathies (IIM), particularly dermatomyositis and polymyositis. It selectively binds to and neutralizes IFN-β, aiming to inhibit IFN-β-mediated inflammatory signaling pathways associated with muscle and skin manifestations of IIM. Dazukibart is currently undergoing Phase III clinical development for dermatomyositis and polymyositis.

Argenx’s efgartigimod is an investigational neonatal Fc receptor (FcRn) antagonist being evaluated for IIM, including dermatomyositis and immune-mediated necrotizing myopathy (IMNM). By selectively binding to and blocking FcRn, efgartigimod reduces the recycling of immunoglobulin G (IgG) antibodies, thereby lowering their circulating levels, including those of disease-causing autoantibodies. This mechanism may help mitigate autoimmune-mediated muscle inflammation and tissue damage. Efgartigimod is currently being evaluated in Phase III clinical trials for active IIM.

Amgen’s Daxdilimab is a fully human monoclonal antibody targeting immunoglobulin-like transcript 7 (ILT7) that works by depleting specific dendritic cell populations. It is under investigation for the treatment of dermatomyositis and anti-synthetase inflammatory myositis. Daxdilimab has completed Phase II clinical evaluation.

The anticipated launch of these emerging therapies are poised to transform the idiopathic inflammatory myositis market landscape in the coming years. As these cutting-edge therapies continue to mature and gain regulatory approval, they are expected to reshape the idiopathic inflammatory myositis market landscape, offering new standards of care and unlocking opportunities for medical innovation and economic growth.

See the idiopathic inflammatory myositis pipeline by phase and company @ Idiopathic Inflammatory Myositis Medications

Recent Developments in the Idiopathic Inflammatory Myositis Market 

• In September 2026, Nkarta announced that NKX019 will be featured in an oral presentation at ACR Convergence 2026, highlighting preliminary safety, pharmacokinetics and pharmacodynamics, and clinical activity in IIM/myositis from the Phase I/II Ntrust studies. IIM-specific data are expected on November 8, 2026.
• In August 2026, Argenx announced positive topline results from the Phase III ALKIVIA study evaluating efgartigimod alfa and hyaluronidase (VYVGART Hytrulo) in adults with autoimmune myositis, supporting its development as a potential treatment option for IIM.
• In August 2026, Rese-cel was granted Regenerative Medicine Advanced Therapy (RMAT) designation by the US FDA for generalized myasthenia gravis, building on its previous RMAT designation for myositis.
• In August 2026, Lakefront Biotherapeutics announced its half-year 2026 financial results and provided a second-quarter and post-period business update, reporting that GLPG3667 completed the Phase II GALARISSO study in dermatomyositis, including its 24-week open-label extension; the company is evaluating strategic options for the GLPG3667 program.
• In July 2026, Fate Therapeutics received FDA IND clearance for FT839, supporting its Phase I/II development in IIM/myositis.
• In June 2026, Argenx announced the presentation of new data on efgartigimod alfa, including IV efgartigimod alfa and SC/Hytrulo efgartigimod alfa with hyaluronidase, in autoimmune rheumatic diseases, including myositis, at the European Alliance of Associations for Rheumatology (EULAR) 2026 Congress held in London.
• In May 2026, Cabaletta Bio announced plans to present multiple oral and poster presentations on rese-cel at the EULAR 2026 Congress (June 3–6, London), including the RESET-Myositis Phase I/II study with longer-term follow-up data from patients with dermatomyositis and ASyS.
• In April 2026, Cabaletta Bio announced multiple manufacturing, translational, and clinical presentations on rese-cel at the ASGCT 2026 Annual Meeting, including a presentation on single-cell profiling of peripheral blood mononuclear cell (PBMC) subsets across the RESET-Myositis Phase I/II trials.
• In March 2026, Abcuro presented Phase II/III MUSCLE clinical study data for ulviprubart at the 6th Global Conference on Myositis (GCOM), supporting its development as an investigational treatment for IBM, a chronic autoimmune disease with no approved treatments.

Idiopathic Inflammatory Myositis Market Report Metrics	Details
Study Period	2022–2036
Coverage	7MM [The United States, the EU4 (Germany, France, Italy, and Spain), the United Kingdom, and Japan].
Idiopathic Inflammatory Myositis Market CAGR	16.8%
Idiopathic Inflammatory Myositis Market Size in 2025	USD 714 Million
Key Idiopathic Inflammatory Myositis Companies	Pfizer, Boehringer Ingelheim, Cabaletta Bio, Abcuro, Amgen, Novartis Pharmaceuticals, Lakefront Biotherapeutics, Argenx, AstraZeneca, RESTEM, Gilead Sciences, Octapharma, Mitsubishi Tanabe Pharma, Priovant Therapeutics, and others
Key Idiopathic Inflammatory Myositis Therapies	Dazukibart, Nerandomilast, CABA-201, Ulviprubart (ABC008), Daxdilimab, Rapcabtagene autoleucel, GLPG3667, Efgartigimod (VYVGART), Anifrolumab (SAPHNELO), RESTEM-L (ULSC), Gamgertamig (OM336), OCTAGAM 10%, VENOGLOBULIN-IH, LISRAYA, and others

What’s the Idiopathic Inflammatory Myositis Market Report Includes?

DelveInsight's Idiopathic Inflammatory Myositis Market Report delivers executive-level intelligence on the evolving market landscape, integrating epidemiology (IIM Diagnosed Prevalent Cases, Type-specific IIM Diagnosed Prevalent Cases, Age-specific IIM Diagnosed Prevalent Cases, Gender-specific IIM Diagnosed Prevalent Cases, Total Treated IIM Cases, and Total Relapsed/Refractory IIM Cases), treatment practices, competitive dynamics, emerging therapies, and market forecasts across the major markets through 2036. Built on a rigorous methodology combining comprehensive secondary research, primary interviews with key opinion leaders and industry experts, and proprietary patient-based forecasting models, the report provides a reliable foundation for strategic planning. Designed for pharmaceutical and biotech executives, it enables informed decisions on portfolio strategy, business development, market entry, investment prioritization, and commercial planning.

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Table of Contents

1	Idiopathic Inflammatory Myositis Market Key Insights
2	Idiopathic Inflammatory Myositis Market Report Introduction
3	Executive Summary of IIM
4	Key Events
5	Epidemiology and Market Forecast Methodology
6	IIM Market Overview at a Glance
6.1	Clinical Landscape (Analysis by Phase, Route of Administration [RoA]), and Molecule Type)
6.2	Market Share (%) Distribution of IIM by Therapies in 2025 in the 7MM
6.3	Market Share (%) Distribution of IIM by Therapies in 2036 in the 7MM
7	Disease Background and Overview of IIM
7.1	Introduction
7.2	Classification
7.3	Etiology and Risk Factors
7.4	Pathophysiology of IIM
7.5	Diagnosis
8	Treatment and Management of IIM
8.1	Treatment Algorithm
8.2	Treatment Guidelines
9	Epidemiology and Patient Population of IIM
9.1	Key Findings
9.2	Assumptions and Rationale
9.2.1	7MM
9.3	Country-Level Summary of Diagnosed Prevalent IIM Cases in the 7MM
9.4	The United States
9.4.1	IIM Diagnosed Prevalent Cases in the United States
9.4.2	IIM Diagnosed Prevalent Cases by Type in the United States
9.4.3	IIM Diagnosed Prevalent Cases by Age in the United States
9.4.4	IIM Diagnosed Prevalent Cases by Gender in the United States
9.4.5	Total Treated IIM Cases in the United States
9.4.6	Total Relapsed/Refractory IIM Cases in the United States
9.5	EU4 and the UK
9.6	Japan
10	Patient Journey of IIM
11	Marketed Therapies of IIM
11.1	Marketed Drugs Competitive Landscape of IIM
11.2	OCTAGAM 10% (Intravenous Immune Globulin [Human]): Octapharma/Pfizer
11.2.1	Product Description
11.2.2	Regulatory Milestones
11.2.3	Other Developmental Activities
11.2.4	Summary of Pivotal Trial
11.2.5	Safety and Efficacy
11.2.6	Analyst Views
11.3	VENOGLOBULIN-IH: Mitsubishi Tanabe Pharma
11.4	Brepocitinib (LISRAYA): Priovant Therapeutics/Pfizer
12	Emerging Therapies of IIM
12.1	Emerging Competitive Landscape of IIM
12.2	Nerandomilast (JASCAYD): Boehringer Ingelheim
12.2.1	Product Description
12.2.2	Other Developmental Activities
12.2.3	Clinical Development
12.2.3.1	Clinical Trial Information
12.2.4	Analyst Views
12.3	Dazukibart: Pfizer
12.4	Efgartigimod (VYVGART): Argenx
12.5	Anifrolumab (SAPHNELO): AstraZeneca
12.6	RESTEM-L (ULSC): RESTEM
12.7	Rese-cel (CABA-201): Cabaletta Bio
12.8	Ulviprubart (ABC008): Abcuro
12.9	Daxdilimab: Amgen
12.10	GLPG3667: Lakefront Biotherapeutics
12.11	Gamgertamig (OM336): Gilead Sciences and Lakefront Biotherapeutics
13	IIM Market: 7MM Market Analysis
13.1	Key Findings
13.2	Idiopathic Inflammatory Myositis Market Outlook
13.3	Conjoint Analysis
13.4	Key Idiopathic Inflammatory Myositis Market Forecast Assumptions
13.5	The 7MM
13.5.1	Total Market Size of IIM by Country in the 7MM
13.5.2	Market Size of IIM by Therapies in the 7MM
13.6	The United States Idiopathic Inflammatory Myositis Market
13.6.1	Total Market Size of IIM in the United States
13.6.2	Market Size of IIM by Therapies in the United States
13.7	EU4 and the UK Idiopathic Inflammatory Myositis Market
13.8	Japan Idiopathic Inflammatory Myositis Market
14	Unmet Needs of IIM
15	SWOT Analysis of IIM
16	KOL Views of IIM
17	Market Access and Reimbursement
18	Bibliography
19	Idiopathic Inflammatory Myositis Market Report Methodology

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