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deflazacort (Emflaza / MP 104 / MP104)

✓ Approved

Marathon Pharmaceuticals · NR3C1 · Steroids

What is deflazacort?

deflazacort is a steroids developed by Marathon Pharmaceuticals. It is approved for therapeutic indications via oral (po).

Drug Profile

Brand NamesEmflaza, MP 104, MP104
CompanyMarathon Pharmaceuticals
Drug ClassSteroids, Small Molecule
Molecular TargetNR3C1
RouteOral (PO)
StatusApproved
Sources: ClinicalTrials.gov, Marathon Pharmaceuticals

Mechanism of Action

Molecular Targets

deflazacort acts on 1 molecular target:

NR3C1nuclear receptor subfamily 3 group C member 1 (GR, GCCR)
Want deeper analysis?Noah AI can explain complex mechanisms and compare to similar drugs.

Therapeutic Indications

deflazacort is developed for 2 unique indications across 2 therapeutic areas.

Therapeutic AreaConditionPhase
Congenital, familial and genetic disordersDuchenne muscular dystrophy✓ Approved
Musculoskeletal and connective tissue disordersJuvenile idiopathic arthritisPreclinical

Related Research Articles

PubMedThe journal of allergy and clinical immunology. In practice2026-11-02

Deflazacort versus prednisolone for weight gain in acute-stage allergic bronchopulmonary aspergillosis: a randomized trial.

Agarwal Ritesh R, Muthu Valliappan V, Sehgal Inderpaul Singh IS, Dhooria Sahajal S et al.

Systemic glucocorticoids are effective in allergic bronchopulmonary aspergillosis (ABPA) but cause adverse effects (AEs). Deflazacort may have fewer metabolic AEs than prednisolone. To evaluate whether deflazacort reduces weight gain while maintaining disease control in ABPA. In this investigator-initiated, single-center, open-label, parallel-group randomized trial, adults with newly diagnosed ABPA were assigned 1:1 to oral prednisolone or oral deflazacort for 16 weeks. The primary outcome was percentage weight gain at eight weeks. Secondary outcomes included decline in serum total IgE, treatment response, ABPA exacerbations, and treatment-emergent AEs (TEAEs). The follow-up was two years. We randomized 178 patients (89 per group; mean age, 35.5 years; 48.3% women). Mean percentage weight gain at eight weeks was lower with deflazacort than prednisolone (2.97% vs. 4.87%; mean difference, -1.9 percentage points; 95% CI, -3.32 to -0.48; p=0.009). Treatment response at eight weeks was similar (95.5% vs. 98.9%; p=0.213). However, the mean percentage decline in serum total IgE from baseline at 16 weeks was smaller with deflazacort (55.2% vs. 62.1%; p=0.024), and one-year ABPA exacerbations were more frequent (18.0% vs. 7.9%; p=0.048). The hazard ratio for the composite outcome of 8-week treatment failure or first subsequent ABPA exacerbation was 1.83 [95% CI, 0.92-3.61]; log-rank p=0.084). TEAEs were similar between groups. Deflazacort reduced early weight gain and achieved similar 8-week treatment response rates, but was associated with a smaller decline in serum total IgE at 16 weeks and more ABPA exacerbations at one year. Further dose-ranging studies are warranted.

PMID 42971324
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PubMedBone reports2026-10-30

Early-onset medication-related osteonecrosis of the jaw in adolescents with Duchenne muscular dystrophy receiving long-term antiresorptive combined with glucocorticoid therapy: Two case reports.

Rio Agathe A, Olivier Patricia P, Leblicq Coralie C, Alos Nathalie N et al.

Youth with Duchenne muscular dystrophy (DMD) are at high risk of osteoporosis due to progressive muscle weakness and chronic glucocorticoid (GC) therapy. Current guidelines recommend routine vertebral fracture screening leading to earlier antiresorptive initiation. Medication-related osteonecrosis of the jaw (MRONJ) is a well-established complication of antiresorptives in adults but is exceedingly rare in youth, with no reported cases in children or adolescents with DMD. We describe two adolescents with DMD who developed MRONJ following dental extraction during antiresorptive therapy for GC-induced osteoporosis. Case 1: A 15-year-old on long-term deflazacort began zoledronic acid at age 11.8 years for a vertebral fracture. MRONJ developed at age 15 post dental extraction, seven months after their last infusion. Case 2: An 18-year-old receiving bisphosphonates from age 8 years, was switched to denosumab at age 18 years. MRONJ occurred six months later, following tooth extraction. In both cases, antiresorptives were suspended and conservative management led to complete healing of MRONJ. Antiresorptives were later resumed for pain and fracture prevention, with no recurrence after one year. Review of more than 1000 pediatric patients treated with bisphosphonates or denosumab identified no prior reports of MRONJ in children or adolescents with DMD. To our knowledge, these are the two youngest reported cases of MRONJ in patients with DMD. They highlight a potential vulnerability related to prolonged GC exposure combined with long-term antiresorptive therapy. Although pediatric MRONJ risk remains extremely low, clinicians should be aware of this complication, particularly when invasive dental procedures are planned.

PMID 42959464
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PubMedJournal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research2026-10-29

Muscle function, linear growth, and bone health during 30 months of vamorolone, prednisone, and deflazacort treatment for Duchenne muscular dystrophy: a comparative study.

Ward Leanne M LM, Jackowski Stefan S, Dang Utkarsh J UJ, B Comm Maya Scharke MS et al.

Corticosteroids are standard of care to slow disease progression in Duchenne muscular dystrophy (DMD) despite impaired growth and increased fracture risk. Vamorolone, a dissociative corticosteroid approved for DMD, showed stable growth and serum bone turnover markers in the 48-week VISION-DMD study. We compared muscle function and bone health from the non-randomized, open-label, 30-month Phase 2a VBP15-002/003/LTE trials (NCT02760264/NCT02760277/NCT03038399) in treatment-naive boys with DMD, aged 4 to <7 years at baseline, with data from matched corticosteroids-treated boys from FOR-DMD (NCT01603407). Motor function by slope-of-change analysis was evaluated for vamorolone 2-6 mg/kg/d through 30 months compared with propensity score-matched boys from FOR-DMD who received daily prednisone (starting dosage 0.75 mg/kg/d) or deflazacort (0.9 mg/kg/d) for 36 months. Anthropometric and bone assessments were performed in boys on vamorolone for 30 months, including those who received lower dosages during VBP15-002/003 (0.25/0.75 mg/kg/d for 6 months). Vertebral fracture (VF) prevalence was compared with baseline-matched FOR-DMD data. Thirty-month vamorolone VF results were adjusted to approximate expected fracture prevalence at 36 months. All slope-of-change motor function comparisons between vamorolone (N=22) and prednisone (N=32) or deflazacort (N=34) groups yielded no significant differences (p>0.05). Thirty-month height z-scores remained stable from baseline for vamorolone (N=36; +0.078 least-squares-mean change) and decreased from baseline for prednisone (N=27, -0.668; change versus vamorolone: p<0.0001 mixed models for repeat measures) and deflazacort (N=28, -0.928; change versus vamorolone: p<0.0001). VF prevalence on vamorolone (8 VF in 5/39 boys [12.8%]) was ~50% lower than prednisone (13 VF in 7/27 boys [25.9%]) and deflazacort (19 VF in 8/28 boys [28.6%]). Compared with prednisone and deflazacort, vamorolone demonstrated similar motor function efficacy with significantly fewer VF and preserved growth.

PMID 42954866
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PubMedGeneral dentistry2026-10-28

Acute methotrexate toxicity with severe oral ulcerations following inadvertent ingestion: a case report.

Alias Ankitha Miriya AM, Srikantannair Sreela Leela SL, SivaPrasad Twinkle T, Mathew Philips P et al.

Inadvertent ingestion of high-risk medications such as methotrexate may lead to serious and potentially fatal complications. This case report describes the oral manifestations observed in a 68-year-old woman who developed acute methotrexate toxicity after inadvertent ingestion of the drug. The patient presented with oral erosions resembling erythema multiforme along with blistering skin lesions that developed over a 2-week period. She was undergoing treatment with hydroxychloroquine, deflazacort, and mirtazapine for inflammatory arthritis. When she presented for evaluation of the mucocutaneous lesions, it was discovered that she had been taking methotrexate (7.5 mg) instead of the prescribed mirtazapine (7.5 mg) for approximately 1 month due to a dispensing error at a local pharmacy. Laboratory investigations revealed bicytopenia involving leukocytes and erythrocytes, likely attributable to acute methotrexate toxicity. Methotrexate was discontinued, and the patient received intravenous folinic acid, benzydamine mouthwash, triamcinolone oral paste, oral antihistamines, and subcutaneous filgrastim. The mucocutaneous lesions resolved, leukocyte counts improved, hemoglobin remained stable at 11.0 g/dL, and the patient was subsequently discharged. This incident draws attention to the critical need for clinicians to remain alert to potential medication errors when erythema multiforme--like lesions are observed in the oral cavity.

PMID 42949941
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PubMedbioRxiv : the preprint server for biology2026-10-25

The annexin A1 mimetic peptide Ac2-26 promotes inflammation-resolution and stimulates skeletal muscle regeneration in the mdx mouse model of Duchenne muscular dystrophy.

Rehman Hamood H, Lu Xinyue X, Nasrallah Savannah M SM, Sharma Binayok B et al.

Duchenne muscular dystrophy (DMD) is an X-linked disorder mainly affecting young boys characterized by repeated cycles of myofiber injury/regeneration and chronic muscle inflammation. Although glucocorticoids can slow disease progression, their potential long-term adverse effects highlight the need for new steroid-sparing therapies for DMD. Annexin A1 (ANXA1) is a glucocorticoid-induced pro-resolving protein that signals primarily through formyl peptide receptor 2 (FPR2). We investigated whether the ANXA1 mimetic peptide Ac2-26 could reduce inflammation, stimulate tissue regeneration, and improve skeletal muscle function in muscular dystrophy. 3-week-old dystrophin-deficient male mdx mice were randomized to receive daily intraperitoneal injections of vehicle control, deflazacort (1 mg/kg/day), or Ac2-26 (1 mg/kg/day) for a duration of 5-weeks. Body composition, skeletal muscle mass, contractile function, and tissue histopathology/immune-cell infiltration were assessed at 8-weeks of age. Direct effects on myogenesis were also examined in vitro using primary D2-mdx myoblasts. ANXA1 was expressed predominantly by myeloid cells rather than resident dystrophic muscle cells. Both deflazacort and Ac2-26 markedly reduced intramuscular inflammation and increased myofiber size. However, Ac2-26 produced broader anabolic and functional benefits, increasing body-weight gain, lean body mass, hindlimb muscle weights, and absolute contractile force. Ac2-26 treatment also directly promoted myogenesis of dystrophic myoblasts in vitro, while pharmacological FPR2 blockade impaired myotube development. Overall, Ac2-26 mimicked the anti-inflammatory effects of deflazacort while providing superior benefits for body weight and composition, skeletal muscle growth, myofiber regeneration, and absolute muscle strength. These findings support therapeutic targeting of the ANXA1-FPR2 axis as a potential safe and effective steroid-sparing immunomodulatory strategy for DMD.

PMID 42926554
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PubMedJournal of medicinal chemistry2026-10-23

Molecular Hybrids of Deflazacort and H2S Donors: From Bench to Potential Treatment for Duchenne Muscular Dystrophy.

Casale Veronica V, Sparaco Rosa R, Cinque Pierfrancesco P, Smimmo Martina M et al.

Duchenne muscular dystrophy (DMD) is an X-linked neuromuscular disorder characterized by oxidative stress, chronic inflammation, and skeletal muscle degeneration. Although deflazacort is the standard treatment, its long-term use is associated with significant adverse effects. Since impaired hydrogen sulfide (H2S) signaling contributes to DMD pathogenesis, we designed five novel deflazacort-H2S donor hybrids (I-V) through a molecular hybridization strategy combining anti-inflammatory efficacy with controlled sulfide release. All hybrids showed chemical stability under physiological and acidic conditions, while serum stability varied according to the linker and donor structure. Compound IV exhibited the longest half-life and a slow, l-cysteine-dependent H2S release profile. In LPS + IFN-γ-stimulated C2C12 myotubes, compound IV reduced (i) NOx production, (ii) expression of pro-inflammatory and redox-related genes, and (iii) intracellular ROS levels. In vivo, compound IV, at half of the deflazacort dose, restored locomotor performance, providing superior protection against oxidative stress, highlighting its potential as a dose-sparing therapeutic candidate for DMD.

PMID 42917938
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