Corticosteroid Hormone Receptor
Vamorolone targets the glucocorticoid receptor (GR) and the mineralocorticoid receptor (MR) with similar affinity. It also acts as a membrane stabilizer and inhibits the pro-inflammatory NF-κB signaling pathway. By binding to the GR, it modulates gene expression, leading to anti-inflammatory effects. Its "dissociative" mechanism means it preferentially promotes NF-κB inhibition (transrepression) over the activation of genes responsible for adverse effects (transactivation). This is achieved through its unique binding mode to the GR, which results in a more favorable side-effect profile compared to classic corticosteroids like prednisone and deflazacort.

At dosages of 1 nM or greater, vamorolone (VBP15) suppresses TNFα-induced pro-inflammatory NF-κB activation in C2C12 ablated cells. Human macrophages that are exposed to vamorolone (0.1, 1 μM) for 30 minutes produce less IL1β and CCL5 mediators in their main tissue [2]. Today's dissociative glucose requirement (GR) ligand and mineralocorticoid receptor (MR)-restricted antagonist is vamorolone [3].
In vitro, Vamorolone binds to the glucocorticoid and mineralocorticoid receptors with high affinity. It inhibits TNFα-induced pro-inflammatory NF-κB signaling in C2C12 muscle cells at concentrations as low as 1 nM. It reduces the levels of NF-κB pathway inflammatory cytokines in mouse primary DIPG cells. Vamorolone also protects cell plasma membranes from physical damage in dystrophin-deficient cells, an effect that is independent of its glucocorticoid receptor activity and contributes to its muscle-stabilizing properties.

When compared to pharmaceutical glucocorticoids, vamolodone (5–30 mg/kg; Cherry) has been demonstrated to cause more substantial side effects in MDX [1]. In mice with experimental autoimmune encephalitis, vamolodone (30 mg/kg; lateral; once daily for 20 days) decreases inflammation of the central nervous system [2].
In vivo, Vamorolone has shown efficacy in various animal models, including those of asthma, multiple sclerosis, inflammatory bowel disease, and muscular dystrophies. In DMD models, it improves muscular dystrophy without the side effects typically associated with corticosteroid therapy. Clinical trials in boys with DMD have demonstrated that vamorolone maintains linear growth, which is a major advantage over traditional corticosteroids that are known to stunt growth. A 12-week, open-label Phase 2 study (VBP15-006) in 2- to <4-year-old and 7- to <18-year-old boys with DMD showed that vamorolone was safe and well-tolerated, with no serious adverse events or negative effects on growth. Patients switching from prior corticosteroid treatment to vamorolone exhibited catch-up growth.

In vitro enzyme/receptor binding (non-cell) assays for Vamorolone are performed using membrane preparations or purified glucocorticoid and mineralocorticoid receptors. These are incubated with a radiolabeled ligand, such as [³H]dexamethasone, and varying concentrations of Vamorolone. Binding affinity (Kd or IC50) is determined by competitive displacement assays. NF-κB activity can be measured in cell lysates using reporter gene assays to assess the compound's anti-inflammatory potential.

In vitro cell-based experiments for Vamorolone are conducted using C2C12 muscle cells or other relevant cell lines. Cells are seeded in plates and treated with Vamorolone at concentrations ranging from 0.1 to 10 µM for various time points. To stimulate the NF-κB pathway, cells are treated with TNFα. Pro-inflammatory cytokine levels (e.g., IL-6, IL-1β) are measured by ELISA, and NF-κB activity is assessed using reporter gene assays. Membrane stabilization is evaluated by measuring the release of lactate dehydrogenase (LDH) from cells subjected to physical or chemical stress.

Animal/Disease Models: C57BL/6 mice (experimental autoimmune encephalomyelitis) [2]
Doses: 30 mg/kg one time/day for 20 days (starting the day before MOG 33-55 peptide immunization and continuing)
Experimental Results: Small diminished central nervous system inflammation in murine experimental autoimmune encephalomyelitis.
In vivo animal experiments for Vamorolone are performed in animal models of DMD (such as the mdx mouse), asthma, multiple sclerosis, and inflammatory bowel disease. Vamorolone is typically administered orally. Disease severity is assessed through various endpoints, including inflammatory markers, muscle function tests (e.g., grip strength, hanging wire test), histopathological analysis of muscle tissue, and overall survival. Efficacy is compared to that of prednisolone or other standard-of-care corticosteroids.

Absorption, Distribution and Excretion
When taken with food, the median Tmax of vamorolone is approximately 2 hours. Taking vamorolone with a high-fat, high-calorie diet decreases Cmax by 18%, increases AUC by 13%, and delays Tmax by 1 hour. Taking vamorolone with a low-fat, low-calorie meal decreases Cmax by 4%, increases AUC by 14%, and delays Tmax by 1 hour. Approximately 30% of the vamorolone dose is excreted in feces (15.4% unchanged) and 48% in urine (<1% unchanged). Based on population pharmacokinetic analysis, the apparent volume of distribution of vamorolone taken with food is 162 L for a 20 kg DMD patient. Based on population pharmacokinetic analysis, the clearance of vamorolone taken with food is 58 L/h for a 20 kg DMD patient.
Metabolism/Metabolites
Vamorolone can be metabolized through multiple pathways, including glucuronidation, hydroxylation, and reduction. Its metabolism is primarily mediated by CYP3A4, CYP3A5, CYP2C8, UGT1A3, UGT2B7, and UGT2B17. Glucuronide—formed through direct glucuronidation and hydrogenation followed by re-glucuronidation—is the main metabolite in plasma and urine.

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Biological Half-Life
The terminal elimination half-life of vamorolone is approximately 2 hours.
Vamorolone is orally bioavailable with good systemic exposure. It has a favorable pharmacokinetic profile with a half-life that supports once-daily dosing. Clinical studies have shown that it exhibits dose-dependent pharmacokinetics, rapid clearance, and no accumulation. Detailed PK parameters, such as Cmax, Tmax, and AUC, have been characterized in both preclinical species and in clinical trials involving DMD patients.

Protein Binding
vamorolone exhibits an in vitro protein binding rate of 88.1%.
Vamorolone has a favorable safety profile with significantly fewer side effects than traditional corticosteroids. In clinical trials, it did not cause the growth suppression or bone density loss typically seen with prednisone or deflazacort. Some weight gain and dose-dependent adrenal suppression have been observed, but these are manageable. It is generally well-tolerated at therapeutic doses.

[1]. VBP15, a novel anti-inflammatory and membrane-stabilizer, improves muscular dystrophy without side effects. EMBO Mol Med. 2013 Oct;5(10):1569-85.

[2]. VBP15, a novel anti-inflammatory, is effective at reducing the severity of murine experimental autoimmune encephalomyelitis. Cell Mol Neurobiol. 2015 Apr;35(3):377-387.

[3]. Vamorolone targets dual nuclear receptors to treat inflammation and dystrophic cardiomyopathy. Life Sci Alliance. 2019 Feb 11;2(1). pii: e201800186.

Vamorolone is a 3-oxo-Δ(1),Δ(4)-steroid with the structure pregnath-1,4,9(11)-trien-17-ol, substituted at positions 3, 20, and 21 with oxo, hydroxyl, and hydroxyl groups, respectively. It has been approved by the U.S. Food and Drug Administration (FDA) for the treatment of patients aged 2 years and older with Duchenne muscular dystrophy. Vamorolone has anti-inflammatory, immunosuppressive, and glucocorticoid receptor agonist effects. It is a corticosteroid, a 3-oxo-Δ(1),Δ(4)-steroid, a 20-oxosteroid, a 17α-hydroxysteroid, a 21-hydroxysteroid, a primary α-hydroxy ketone, and a tertiary α-hydroxy ketone. Vamorolone is a novel, fully synthetic glucocorticoid developed by Santhera Pharmaceuticals. It is used to treat inflammation and immune dysregulation in patients with Duchenne muscular dystrophy (DMD). Duchenne muscular dystrophy (DMD) is a neuromuscular disease characterized by progressive neuromuscular degeneration and is the most common type of muscular dystrophy in the United States. Despite a relatively high incidence of adverse reactions, corticosteroid therapy remains the standard treatment for DMD. Due to its unique receptor-binding properties, Vamorolone has a more tolerable spectrum of adverse reactions compared to other corticosteroids, thus providing a new treatment option for patients who cannot tolerate or accept the adverse effects of corticosteroids. Vamorolone was approved by the US FDA in October 2023 for the treatment of Duchenne muscular dystrophy (DMD) in patients aged 2 years and older. In December 2023, it was approved in the European Union for the treatment of patients aged 4 years and older. Vamorolone is a corticosteroid. Its mechanism of action is as a corticosteroid hormone receptor agonist. Vamorolone is indicated for the treatment of Duchenne muscular dystrophy (DMD) in patients aged 2 years and older in the United States and in patients aged 4 years and older in the European Union.
Treatment of Duchenne Muscular Dystrophy

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Mechanism of Action
Vamorolone is a synthetic corticosteroid that acts as a glucocorticoid receptor agonist, exerting anti-inflammatory and immunosuppressive effects. It is also a mineralocorticoid receptor antagonist. The exact mechanism by which vamorolone exerts its therapeutic effect in patients with DMD is unclear.

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Pharmacodynamics
In clinical studies, vamorolone treatment resulted in a dose-dependent decrease in morning cortisol levels and a dose-dependent increase in white blood cell and lymphocyte counts.
Vamorolone is also known as VBP15. It is FDA and EMA-approved for DMD. Its development and approval represent a major breakthrough in the treatment of this devastating disease. Ongoing and future studies are exploring its potential in other inflammatory and autoimmune conditions. It is the first dissociative steroid to be approved for any indication.

C22H28O4

356.45532

356.199

C, 74.13; H, 7.92; O, 17.95

13209-41-1

13209-41-1; 10106-41-9 (acetate)

3035000

White to yellow solid powder

1.24g/cm3

548.3ºC at 760 mmHg

299.4ºC

2.63E-14mmHg at 25°C

1.603

2.752

2

4

2

26

775

6

C[C@@H]1C[C@H]2[C@@H]3CCC4=CC(=O)C=C[C@@]4(C3=CC[C@@]2([C@]1(C(=O)CO)O)C)C

ZYTXTXAMMDTYDQ-DGEXFFLYSA-N

InChI=1S/C22H28O4/c1-13-10-18-16-5-4-14-11-15(24)6-8-20(14,2)17(16)7-9-21(18,3)22(13,26)19(25)12-23/h6-8,11,13,16,18,23,26H,4-5,9-10,12H2,1-3H3/t13-,16-,18+,20+,21+,22+/m1/s1

(8S,10S,13S,14S,16R,17R)-17-hydroxy-17-(2-hydroxyacetyl)-10,13,16-trimethyl-7,8,12,14,15,16-hexahydro-6H-cyclopenta[a]phenanthren-3-one

Agamree; vamorolone; 13209-41-1; 17,21-Dihydroxy-16alpha-methylpregna-1,4,9(11)-triene-3,20-dione; VBP-15 free alcohol;

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ~62.5 mg/mL (~175.34 mM)

Solubility in Formulation 1: ≥ 2.08 mg/mL (5.84 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.08 mg/mL (5.84 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 2.08 mg/mL (5.84 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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 (Please use freshly prepared in vivo formulations for optimal results.)