in pictures and a few words
What it is and why it matters
Vamorolone is a hormone medicine for Duchenne muscular dystrophy. Children and adults are given it instead of the usual hormone, not together with it.
- In the US it was approved in 2023, and it can be taken from age 2
- It calms inflammation like the usual hormone
- But it affects growth and bones less
What goes wrong in this disease
Muscle has a shock-absorber protein. It keeps the muscle fibre intact when the muscle contracts. In this disease, because of a broken gene, this protein is missing.
- Each contraction damages the muscle a little
- First the child finds it hard to run, then to walk
- Almost only boys are affected
Why hormones are needed
Hormones do not fix the gene. But they calm the inflammation around damaged fibres and so slow down muscle breakdown.
- They extend the ability to walk by years
- But the usual hormones have a price: the child grows worse, bones become brittle, weight goes up
Tested in people. Tested in people: hormones extend the ability to walk by years.
How it works
The usual hormone switches on many programmes in the cell at once: some calm inflammation, others slow bone growth. Vamorolone sits in the same place but does not switch them all on.
- Protection against inflammation stays
- It affects growth and bones less
- It holds less water in the body
How it helps muscles
In the study, boys on vamorolone got up from the floor faster than on a dummy pill.
- Other tests were also better, including a 6-minute walk
- After almost a year the benefit was still there
- The benefit for muscles is comparable to the usual hormone
Tested in people. Tested in people: in boys with this disease, compared with a dummy pill.
The child keeps growing
Children on the usual hormone fell further and further behind their peers in height, but children on vamorolone did not.
- Tests showed that bone renewal was not suppressed on vamorolone
- On the usual hormone it was suppressed
Tested in people. Tested in people: children on vamorolone compared with children on the usual hormone.
Switching from the usual hormone
When children were switched from the usual hormone to vamorolone, they started to grow better, and bone measures returned to normal.
- A doctor plans the switch
- The previous hormone is not stopped abruptly
Tested in people. Tested in people: in children switched from the usual hormone to vamorolone.
How it is taken
Vamorolone is given instead of the usual hormone, not together with it: two such hormones are not prescribed at once.
- Physiotherapy, heart and breathing checks and orthopaedic follow-up all remain
- In the first six months weight may go up, then it levels off
Who should see a doctor first
Vamorolone, like the usual hormone, weakens the work of the adrenal glands — small glands above the kidneys. So the safety rules are the same.
- Not suitable during an active infection or where any such hormones are not allowed
- Not given together with the usual hormone — only instead of it
- The previous hormone is not stopped abruptly: a doctor plans the switch
Important. Vamorolone must not be stopped abruptly. During illness, injury or surgery the dose needs adjusting — the family is told this before treatment starts.
In one sentence
Vamorolone calms inflammation in the muscles like the usual hormone, but gets in the way of a child’s growth less and affects bones less; it is given instead of the usual hormone, on a doctor’s plan.
Key points
Vamorolone (brand name Agamree) is a dissociative steroid: approved by the FDA in October 2023 for Duchenne muscular dystrophy from age 2, it is given to children and adults in place of a conventional glucocorticoid.
| Where | How it helps | What human studies showed |
|---|---|---|
| Muscle and movement | keeps the anti-inflammatory action | VISION-DMD, 121 boys, 24 weeks: on 6 mg/kg/day, time-to-stand velocity 0.05 m/s versus −0.01 m/s on placebo (p=0.002) [1] |
| Growth | weaker effect on growth than prednisone | growth percentile fell by 1.88 on prednisone and rose by 3.86 on vamorolone 6 mg/kg (p=0.02) [1] |
| Bone | did not suppress bone turnover in the trial | bone turnover markers declined on prednisone, not on vamorolone [1] |
| Switching from prednisone | growth improves, bone measures return toward normal | growth improved and bone measures returned toward normal [2] |
| Fluid retention | attenuated: blocks the mineralocorticoid receptor | — |
How it helps
What Breaks in This Disease
The muscle fibre has a shock-absorbing protein: dystrophin. It holds the fibre's membrane intact during contraction. In Duchenne muscular dystrophy the dystrophin gene is damaged and the protein is not made.
The result: every contraction damages the muscle a little. Fibres die and are replaced by fat and connective tissue. First the child loses the ability to run, then to walk; later the respiratory muscles and the heart are affected. Almost only boys are affected.
Why Steroids Cannot Be Avoided
Glucocorticoids do not repair the gene or restore dystrophin. But they damp the inflammation that accompanies fibre breakdown, and thereby slow the destruction. They are proven to extend the ability to walk by years.
So they are not abandoned, though the cost is high — and highest for a growing child:
▸growth delay; ▸fragile bones, vertebral fractures; ▸weight gain; ▸cataract; ▸changes in behaviour and mood; ▸adrenal suppression.
The Same Receptor, a Different Set of Programmes
An ordinary glucocorticoid entering the cell binds its receptor — and switches on a whole set of programmes at once. Some damp inflammation, others slow bone growth, others alter metabolism. It all arrives as one package.
Vamorolone binds the same receptor but does not activate the entire set: the anti-inflammatory part is kept, while some of the pathways leading to growth delay and bone loss are engaged less. It additionally blocks the mineralocorticoid receptor, associated with fluid retention.
Hence the name of the class — dissociative steroids: they separate what is inseparable in ordinary hormones.
What the Trial Showed
▸VISION-DMD (JAMA Neurology, 2022) — 121 boys, mean age 5.4 years, 24 weeks [1].
The primary measure was time-to-stand velocity, an ability that deteriorates earlier than many others in this disease. On 6 mg/kg per day it was 0.05 m/s versus −0.01 m/s on placebo (95% CI 0.02–0.10; p=0.002). The first four secondary endpoints were also met, the six-minute walk test among them.
The most important part is the comparison with prednisone (figures in “Key points”): the difference is not one of degree but of direction — one group fell further behind their peers, the other did not.
▸48-week extension (Neurology, 2024) — motor improvement was maintained. In children switched from prednisone to vamorolone, growth improved and disturbed bone measures returned toward normal [2].
How to take it
Vamorolone is taken in place of a conventional glucocorticoid, as planned by a physician; in the trial the effect was shown on 6 mg/kg per day [1].
Who should see a doctor first
Who It Is Not For
▸As an addition to a conventional glucocorticoid: it is a replacement, not an add-on — two steroids are not prescribed together. ▸During active infection and in other situations where any glucocorticoid is contraindicated. ▸As grounds for stopping the previous hormone abruptly: the switch is planned by a physician, accounting for suppressed adrenal function. ▸As a substitute for the rest of care: physiotherapy, cardiac and respiratory monitoring and orthopaedic follow-up all remain.
Bottom Line
▸The same receptor, a different set of programmes: anti-inflammatory action preserved, impact on growth and bone attenuated. ▸The motor effect is proven against placebo: time-to-stand velocity 0.05 versus −0.01 m/s. ▸Switching from prednisone returned growth and bone measures toward normal.
Treatment can be discussed at a consultation; the drug can be ordered here.
References
1. Guglieri M, et al. Efficacy and Safety of Vamorolone vs Placebo and Prednisone Among Boys With Duchenne Muscular Dystrophy: A Randomized Clinical Trial. JAMA Neurol. 2022;79(10):1005–1014. PMID 36036925
2. Dang UJ, et al. Efficacy and Safety of Vamorolone Over 48 Weeks in Boys With Duchenne Muscular Dystrophy: A Randomized Controlled Trial. Neurology. 2024;102(5):e208112. PMID 38335499
3. Ahmet A, et al. Adrenal Suppression From Vamorolone and Prednisone in Duchenne Muscular Dystrophy. J Clin Endocrinol Metab. 2025;110(2):334–344. PMID 39097643
4. AGAMREE (vamorolone) — US Prescribing Information, Catalyst Pharmaceuticals.
Caveats
- Comparison with prednisone. The trial was designed against placebo, not for superiority over prednisone, so it cannot be claimed that vamorolone is more effective than prednisone for muscle [1].
- Side effects attenuated, not eliminated. Adrenal suppression is a class property and it was not circumvented [3]; body mass index rose over the first 24 weeks and then stabilised [2].
- Duration. The longest follow-up is 48 weeks, while treatment in this disease is lifelong.
- Heart. There is no separate evidence here on Duchenne cardiomyopathy.
This material is for information and does not replace a consultation with a physician.
Key facts
- Vamorolone (brand name Agamree, Catalyst Pharmaceuticals) is a dissociative steroid approved by the FDA in October 2023 for Duchenne muscular dystrophy in patients from 2 years of age; it is given in place of a conventional glucocorticoid.
- Vamorolone binds the same glucocorticoid receptor as prednisone but does not trigger its full set of programmes — keeping the anti-inflammatory action while touching growth and bone metabolism less.
- VISION-DMD (JAMA Neurology, 2022): 121 boys, mean age 5.4 years; time-to-stand velocity improved on 6 mg/kg/day — 0.05 m/s versus −0.01 m/s on placebo (p=0.002).
- Growth percentile fell by 1.88 in children on prednisone and rose by 3.86 on vamorolone (p=0.02); bone turnover markers declined on prednisone and did not decline on vamorolone.
- The 48-week extension (Neurology, 2024): motor improvement was maintained, and in children switched from prednisone to vamorolone growth and bone measures recovered; the switch is planned by a physician, and, as with any steroid, the previous hormone is not stopped abruptly.
