Update – 18 September 2025
We’re pleased to share that following these encouraging results, vorasidenib has been approved by the Medicines and Healthcare products Regulatory Agency (MHRA) to treat adults and children 12 years and older who have a grade two astrocytoma or oligodendroglioma with an IDH1 or IDH2 mutation.
While this doesn’t mean that vorasidenib is available on the NHS, it is available privately.
The next step is for the National Institute for Health and Care Excellence (NICE) to evaluate the drug to determine whether it’s suitable for use within the NHS in England. We’ve submitted evidence as part of this process and expect that a decision will be made by December 2025.
We welcome the MHRA approval as it could be a step towards a new, targeted treatment for some of the most common low grade brain tumours being made widely available in the UK.
If you’d like to learn more about the process that a new drug needs to go through before becoming available on the NHS, we recently featured it in The Grey Matters #31 (p8-11).
In this post, we’ll discuss:
- What vorasidenib is
- What IDH1 and IDH2 enzymes are, and how vorasidenib works against them
- Who was part of the trial
- The results of the trial
- Why the trial is important
- Accessing vorasidenib
- What our expert thinks
What is vorasidenib?
The drug vorasidenib inhibits the enzymes IDH1 and IDH2 and is able to cross the blood-brain barrier.
What are IDH1 and IDH2 enzymes? And how does vorasidenib work against them?
IDH or isocitrate dehydrogenases are a group of enzymes that are important in cell metabolism (how cells get their energy). They play an important role in various biological processes in the body.
Mutations in the DNA that code for IDH1 and IDH2 occur in the majority of low-grade gliomas (1). Therefore the discovery of a drug that can target IDH1 and IDH2 and reduce disease progression could offer a new treatment option for those diagnosed with this type of tumour.
Who was part of the trial?
The trial involved 331 patients aged 12 and over. They had residual or a recurrent grade 2 glioma with an IDH mutation.
Of the 331 patients, 168 were randomly assigned vorasidenib and 163 were randomly assigned the placebo.
After the trial ended, those who had received the placebo were then given access to vorasidenib due to its ability to slow disease progression.
What did the trial show?
The clinical trial showed that vorasidenib more than doubled the length of time until tumour progression compared to placebo (27.1 months vs 11.1 months).
Results also showed that the time to next treatment intervention was significantly reduced in those treated with vorasidenib compared to placebo (85.6% likelihood of not receiving intervention in the next 18 months vs 47.4% likelihood).
Additionally, the trial showed that treatment with vorasidenib had low levels of toxic effects for patients.
The researchers published these results in the New England Journal of Medicine.
Why is this so important?
Gliomas with an IDH mutation are the most common primary, malignant brain tumour affecting people under 50 years old (2). They are not curable and will continue to grow if they are not treated.
Nearly all grade 2 gliomas have an IDH mutation and include astrocytomas and oligodendrogliomas.
Current standard-of-care consists of surgical resection, followed by radiation and chemotherapy in selected patients (3). These treatments are highly toxic in the body and have many side effects. Therefore, there is a desperate need for new and more targeted treatment options with fewer side effects.
Is vorasidenib currently approved anywhere?
Yes, in August 2024 vorasidenib was approved by the FDA in the USA to treat low-grade glioma.
Additionally, approval is under review in the EU where the EMA granted accelerated access assessment in February 2024.
The drug is also being reviewed in Canada.
It is not currently licensed in the UK.
What does our expert think?
Dr Simon Newman, Chief Scientific Officer at The Brain Tumour Charity, said:
“Research into low-grade gliomas is vitally important. Finding new, targeted treatments is essential if we are to improve the quality of life for those living with a brain tumour and accelerate towards a cure.
“This study shows promising results, and seeing that vorasidenib can more than double the time of progression free survival in patients is very encouraging.
“We hope that more people can have access to innovative treatments such as this because we urgently need kinder, more effective treatments for those facing this devastating diagnosis.
“Now vorasidenib has been approved by the FDA, we hope it will get quick review, so it can then be assessed by NICE and other health technology assessment (HTA) bodies.”
References
- 1. Cohen, A.,Holmen S., and Colman, H. (2013). ‘IDH1 and IDH2 Mutations in Gliomas’, Current Neurology and Neuroscience Reports. 13(5):345. Access: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4109985/
- 2. Mellinghoff, IK., et al. (2023). ‘Vorasidenib in IDH1- or IDH2-Mutant Low-Grade Glioma’, The New England Journal of Medicine. Access: https://www.nejm.org/doi/full/10.1056/NEJMoa2304194
- 3. Youssef, G and Miller, J J. (2020). ‘Lower Grade Gliomas’, Current Neurology and Neuroscience Reports. 20, 21. Access: https://link.springer.com/article/10.1007/s11910-020-01040-8
Donate today
To help us move further, faster towards a world where brain tumours are defeated.