Breakthrough BBS10 treatment marks major milestone
Catherine L’Estrange, aged 11 from London has become the first individual in the UK to receive an investigative gene therapy treatment for retinal dystrophy associated with the BBS10 gene.
Catherine L’Estrange, aged 11 from London has become the first individual in the UK to receive an investigative gene therapy treatment for BBS10-associated retinal dystrophy. Mutations in the BBS10 gene are the second most common cause of Bardet Biedl syndrome (BBS); see below for more information about this condition.
The treatment, developed by MeiraGTx, has been provided under an MHRA Specials Licence. The programme is limited to a very small number of identified patients and eligibility has already been determined by the specialist clinical team leading the treatment. Retina UK was not involved in this process and cannot influence an individual’s eligibility to receive this treatment.
This is an exciting and significant milestone for our BBS community and an encouraging step forward in research towards potential treatments. If you’d like to hear more about exciting research developments in the inherited retinal disease space, register for our Annual Conference in-person or online now by following the link here
To read Catherine’s amazing story please follow the link here.
FAQs:
What is Bardet-Biedl syndrome (BBS)?
Individuals with BBS experience retinal degeneration that is similar to retinitis pigmentosa (RP). In addition to RP, this condition is accompanied by abnormalities of the fingers and/or toes, obesity, kidney disease and sometimes developmental delay and learning difficulties.
More than 20 causative genes are known and mutations in the BBS10 gene account for more than 20% of all cases. BBS10 mutations lead to abnormal function of tiny cell structures called cilia, which are essential for many tissues, including the light-sensing photoreceptor cells of the retina. Without a working BBS10 protein retinal cells gradually become dysfunctional leading to photoreceptor degeneration and as such vision loss. To read more about BBS, please visit our page here.
For more support with non-vision related aspects of BBS, please visit the BBS UK website found here.
What is the treatment?
BBS10 is an investigative gene therapy treatment in development by MeiraGTx for people with Bardet-Biedl syndrome caused specifically by mutations in the BBS10 gene. It is designed to treat the retinal disease (vision loss) associated with BBS10 mutations. It is not a treatment for the other features of BBS, such as obesity or kidney disease.
The treatment is delivered via a subretinal injection, after a vitrectomy has been performed in surgery. This involves removing the gel (vitreous) from the eye and injecting the gene therapy under the retina. The treatment is given in one eye to assess safety and efficacy with long term follow ups.
The gene therapy contains a healthy copy of the BBS10 gene and is delivered via an adeno-associated viral vector. This means that a small virus, that doesn’t cause illness in humans, is used as a delivery system to introduce or alter genetic material within cells.
What is the goal for this treatment?
The goal of this therapy is to deliver a functioning BBS10 gene that allows for the normal production of the BBS10 protein which is important for cellular functions to occur. This therapy is not expected to revive retinal cells that have already died but rather aims to preserve the remaining healthy cells.
Researchers hope the treatment will slow or halt vision loss, preserve useful vision for longer and potentially produce modest improvements in some aspects of vision such as low-light vision. This is why earlier treatment is expected to provide the greatest benefit. However, patients are not expected to regain normal eyesight.
Who is it for?
It is important to understand that this treatment is specifically designed for retinal disease caused by mutations in the BBS10 gene only. It does not treat the other features of Bardet-Biedl syndrome, nor is it suitable for retinal disease caused by other BBS genes.
We understand that this treatment will only be suitable for a small proportion of our community, however it reflects an important milestone for BBS research. At Retina UK we know that there is still so much work to be done and we remain committed to supporting research into treatments until everyone who hears the devastating news that they have an inherited sight loss condition is also told a treatment is available.
Who can access it?
The treatment has been provided under an MHRA Specials Licence as part of a physician-led treatment protocol. An MHRA Specials licence is a UK regulatory mechanism that allows a doctor to prescribe an unlicensed medicine for an individual patient when there is no suitable licensed alternative available to meet that patient’s specific clinical needs. It is not the same as full regulatory approval or a clinical trial.
For people with BBS10-associated retinal degeneration, there is currently no licensed therapy. For a small number of patients, specialists determined that the potential benefit of the experimental treatment justified its use before formal approval, so it was supplied under the MHRA Specials framework. This allows eligible patients to receive the therapy before clinical studies and the regulatory review process take place.
Although this is not a clinical trial, patients receiving treatment will be followed for at least 12 months to assess its safety and gather further evidence. Our understanding is that at present, the programme is limited to a very small number of carefully identified patients, and eligibility has already been determined by the specialist clinical team leading the treatment.
Retina UK was not involved in this process and cannot influence an individual’s eligibility to receive this treatment.
To read more about BBS10 or MeiraGTx, please visit their website here. Please do contact them directly if you have any further questions about this treatment.
What do RPDD and Orphan Drug designation mean?
BBS10 has received regulatory designations to help speed up its development, such as Orphan Drug and Rare Paediatric Disease Designation. However, it remains in the early stages of research and will require further testing and regulatory approval before it could become widely available. Different regulatory bodies operate in the US, UK, Europe and elsewhere and designations do not transfer across regions. Obtaining regulatory approval can take a long time, even if MeiraGTx seeks to work with all of them and reaching agreement for NHS availability is a further, separate process.
Orphan Drug is a status for treatments aimed at rare diseases. This status could come from regulatory bodies in the US, UK, Europe or elsewhere, but remains specific to each regulatory body. It gives companies incentives like market exclusivity, fee reductions and support for development. This is often more important for attracting investors and helping companies fund trials than for proving the treatment works. It’s a positive milestone, but an early one. As the designation is regulatory body-specific, even if a promising treatment has received orphan drug status in the US, it may not have the same status or incentives in the UK. The drug can still progress through clinical trials and may eventually be approved, but any special support or fast-track benefits linked to orphan status would only apply if the MHRA grants it.
Rare Paediatric Disease (RPD) designation is an FDA-specific programme designed to encourage the development of treatments for serious rare diseases that primarily affect children. This programme is US specific and does not affect the UK regulatory pathway. RPD designation does not mean that a treatment has been shown to work, or that it’s guaranteed for approval. However, it is an important milestone because it recognises that the therapy is being developed for a serious rare paediatric condition and may help encourage continued investment in its development. FDA decisions and designations can also influence global development programmes and may support future regulatory submissions in the UK and Europe if the company chooses to pursue them.