What is the new drug for myositis? Exploring Breakthroughs and Emerging Treatments

October 12, 2025 •

3 min read

For years, patients with myositis relied on older immunosuppressants and corticosteroids, but the landscape is rapidly evolving with new, targeted therapies. A key advancement is Octagam 10% (Intravenous Immunoglobulin or IVIg), which received FDA approval in 2021 specifically for adult dermatomyositis. This milestone highlights significant progress in answering the question, 'What is the new drug for myositis?'

Quick Summary

The treatment for myositis is advancing with new therapies beyond traditional immunosuppressants. Recent breakthroughs include the FDA approval of IVIg for dermatomyositis and promising drug candidates like CAR T-cell therapies and JAK inhibitors in clinical trials. These targeted approaches offer new hope for patients with different myositis subtypes.

Key Points

Octagam 10% (IVIg) is FDA-Approved for Dermatomyositis: As of 2021, Octagam 10% became the first and only intravenous immunoglobulin (IVIg) specifically approved by the FDA for treating adult dermatomyositis, a significant step beyond off-label use.
Diverse Pipeline of New Therapies: Numerous new drugs are in clinical trials for various myositis subtypes, including JAK inhibitors (e.g., Tofacitinib, Baricitinib), monoclonal antibodies (e.g., Efgartigimod, Dazukibart), and complement inhibitors (e.g., Ruxoprubart).
CAR T-Cell Therapy Offers New Hope: Advanced cellular therapies like CABA-201 and Descartes-08 are being investigated for their potential to 'reset' the immune system in myositis by targeting B-cells, potentially leading to long-term remission.
Treatment Approaches are Subtype-Specific: Research increasingly shows that different myositis subtypes have distinct underlying mechanisms. Therapies are becoming more targeted based on autoantibody profiles and specific inflammatory pathways.
Inclusion Body Myositis (IBM) Remains Challenging: Despite advancements in other myositis forms, IBM still lacks an effective drug treatment. Research is focused on novel approaches like gene therapy and targeting specific immune cells, but no approved drug is available.
Combination Therapies are Emerging: Clinical practice often involves using a combination of drugs to manage complex or refractory cases. For example, some clinicians use rituximab and IVIg together for better outcomes in refractory inflammatory myositis.

The field of myositis treatment has shifted from broad immunosuppression to targeted therapies. A major development was the FDA approval of Octagam 10% (IVIg) for adult dermatomyositis in July 2021, the first proven treatment specifically for a myositis indication. Many other novel agents are also in clinical trials.

Recent FDA-Approved and Emerging Therapies

FDA Approval: Octagam 10% (IVIg)

Octagam 10% was approved by the FDA in July 2021 for adult dermatomyositis. IVIg is a blood product that modulates the immune system and was shown to be safe and effective in the ProDERM trial. It is particularly useful for patients who haven't responded to standard treatments.

JAK Inhibitors: Targeting Inflammatory Pathways

JAK inhibitors block the JAK-STAT pathway involved in myositis inflammation. Several are being studied:

Tofacitinib: Shows promise for skin-predominant dermatomyositis and high-risk anti-MDA5-positive myositis.
Baricitinib: In a Phase 3 trial for moderate to severe dermatomyositis.
Brepocitinib: Also being investigated for dermatomyositis.

Monoclonal Antibodies: Highly Targeted Approaches

Monoclonal antibodies target specific immune system components.

Efgartigimod: An FcRn antagonist in the ALKIVIA study for idiopathic inflammatory myopathies (IIM), showing significant treatment effects in Phase 2.
Dazukibart: Targets IFN-beta and shows promise for dermatomyositis.
Anifrolumab: Also targets the type 1 interferon pathway and is in a Phase 2 trial for IIM.
Rituximab: An older biologic used off-label for refractory myositis.

Advanced Therapies: Cellular and Complement Targeting

CAR T-Cell Therapy: Resetting the Immune System

CAR T-cell therapy, used in cancer, shows potential for autoimmune diseases like myositis. It re-engineers a patient's T-cells to target and eliminate B-cells that produce autoantibodies.

CABA-201: An investigational CAR T-cell therapy in clinical trials for several myositis subtypes.
Descartes-08: An mRNA-based CAR T-cell therapy with FDA Rare Pediatric Disease designation for juvenile dermatomyositis.

Complement Pathway Blockers

These therapies target complement activation, which drives inflammation in some myositis subtypes.

Ruxoprubart (NM8074): A selective blocker of the alternative complement pathway with FDA IND clearance for dermatomyositis in February 2025. It may be safer than broader approaches.
Ravulizumab: A C5 inhibitor in a Phase 3 study for adult dermatomyositis patients with inadequate response to prior therapies.

The Challenging Case of Inclusion Body Myositis (IBM)

Inclusion body myositis (IBM) remains difficult to treat with no FDA-approved drug. Research includes:

Follistatin Gene Therapy: Experimental therapy to potentially increase muscle growth.
Targeting KLRG1+ Cells: Exploring therapeutic benefits by targeting these cells found in IBM patients.

Comparison of Myositis Treatments


Treatment Type	Examples	Target/Mechanism	Development Status	Primary Benefits	Key Considerations
IVIg	Octagam 10%	Broad immunomodulation	FDA-approved for DM	Proven efficacy in DM, treats refractory cases	Can be costly, requires intravenous administration, potential for side effects like headache and thrombosis
JAK Inhibitors	Tofacitinib, Baricitinib	JAK-STAT pathway signaling	Clinical trials for multiple subtypes	Oral administration, targeted mechanism, potential for skin and lung improvement	FDA warnings for potential side effects, long-term safety data still emerging
CAR T-cell Therapy	CABA-201, Descartes-08	B-cell depletion and immune reset	Early clinical trials	Potential for long-term, drug-free remission	Highly specialized treatment, potential for significant adverse events like cytokine release syndrome
Monoclonal Antibodies	Efgartigimod, Dazukibart	FcRn or IFN pathways	Clinical trials	Highly specific immune targeting, functional improvement	Side effect profiles differ by target, long-term data being collected
Complement Inhibitors	Ruxoprubart, Ravulizumab	Alternative or C5 pathway	Clinical trials	Specific targeting of complement, potentially safer than broad immunosuppressants	Negative trial result for another complement inhibitor (Zilucoplan) in IMNM

Conclusion: A Shift Towards Personalized Medicine

The myositis treatment landscape is rapidly changing with new targeted therapies emerging based on a deeper understanding of disease mechanisms. The FDA approval of IVIg for adult dermatomyositis was a key step towards evidence-based, myositis-specific treatment. The pipeline of new drugs, including JAK inhibitors and CAR T-cell therapies, offers promising, personalized options, particularly for refractory cases and those with specific autoantibodies. The future of myositis management is moving towards precision medicine, aiming to improve outcomes and quality of life.

For more information on the latest research and ongoing trials, visit the Myositis Association website.

Frequently Asked Questions

The most recently FDA-approved drug specifically for adult dermatomyositis is Octagam 10%, an intravenous immunoglobulin (IVIg) treatment. It was approved in 2021 based on a Phase 3 clinical trial.

Currently, there is no effective drug treatment for inclusion body myositis. However, research is ongoing, including studies on therapies like follistatin gene therapy and immune cell targeting, but these are still in the experimental stages.

CAR T-cell therapies, such as CABA-201, work by genetically modifying a patient's own T-cells to attack and deplete B-cells, which are responsible for producing the autoantibodies that cause myositis. This can potentially 'reset' the immune system.

JAK inhibitors, including tofacitinib and baricitinib, target the Janus kinase (JAK) signaling pathway to reduce inflammation. They are being studied for use in various forms of myositis, particularly for managing skin and lung symptoms.

While the FDA has not approved a new drug for juvenile dermatomyositis (JDM), it has granted rare pediatric disease designation to Descartes-08, an mRNA CAR T-cell therapy, paving the way for its future development.

Ruxoprubart (NM8074) is a new investigational drug that targets the alternative complement pathway, a part of the immune system that contributes to inflammation. It received IND approval in early 2025 for dermatomyositis.

Yes, for patients with refractory myositis (those who do not respond to standard therapy), new options are emerging. These include the FDA-approved IVIg for DM, monoclonal antibodies like efgartigimod and dazukibart in clinical trials, and potentially CAR T-cell therapy.