An Eye on the Higher Branches
Using advanced therapies to tackle the huge burden of inherited sight loss
Angus Stewart | | 4 min read | Interview
Marianthi Psaha, Global Head Cell & Gene Therapy at Santen Pharmaceutical, shares what progress is being made in using cell and gene therapies in ophthalmology, and why the field is so important.
To date, why do you think oncology has been the primary focus for cell and gene therapy?
As an often life-threatening condition, oncology is an obvious first target for cell and gene therapy. Ophthalmology may not have received quite as much initial attention, but in rare ophthalmic diseases in particular, there is a significant unmet need that cell and gene therapies can help address.
How could advanced therapies help ophthalmology patients?
I believe it is important to focus on inherited retinal diseases – a group of diseases that cause progressive sight loss and an area that Santen is passionate about. For the majority of these diseases, there are currently no licensed treatments. Once diagnosed, patients must often “go home and go blind,” as nothing can be done for them from a medical point of view. The progressive and unpredictable nature of the sight loss associated with these diseases inflicts a huge burden on every aspect of patients’ lives: from education and employment to their ability to communicate with others and participate in sports or other leisure activities. The emotional impact is huge – often going beyond just the patient, and affecting entire families. Cell and gene therapies could help change that.
Why are we now seeing more breakthrough cell and gene therapies for the eye?
When compared with other organs, the eye offers certain unique advantages for cell and gene therapies. For example, it is one of the few sites in the body that possesses a certain degree of immune privilege. And that means the risk of immune rejection is relatively low (compared with other parts of the body). As a result, some technologies, such as allogeneic cell therapies, have significant potential in ophthalmology.
At Santen Cell & Gene, our current lead asset is an investigational human retinal progenitor cell (hRPC) allogeneic therapy targeting retinitis pigmentosa (RP) – one of the leading causes of inherited blindness (1). It offers a number of advantages, including the potential to be administered through intravitreal delivery, a minimally invasive procedure. Additionally, it is gene-agnostic – a significant benefit given that RP can be caused by over 100 different genes. For the same reason, our therapy could have applicability in additional retinal indications.
The global cell and gene therapy market is expected to reach $21.33 billion in 2026 at a CAGR of 25.6%. It’s clear that addressing previously unmet medical needs can lead to a significant growth opportunity (3).
When it comes to cell and gene therapy commercialization, what ophthalmology-specific barriers do you face?
At Santen, we often refer to a line from the World Health Organization’s World Report on Vision: “The world is built on the ability to see,” (2). But, despite vision being a critical part of our daily lives, there is often a tendency to overlook eye health in favor of more “serious” or life-threatening conditions in the healthcare community beyond ophthalmology. Though it is true that most eye conditions are not life threatening, the potential impact that improved vision could have not only on patients’ quality of life but also on the economy and society as a whole is tremendous.
For example, inherited retinal diseases cost the US economy an estimated $4 billion in lost productivity (4, 5). Therefore, one of our challenges lies in highlighting the transformative potential of these types of therapies to regulators, payers, and other key stakeholders. Though they may not cure a life-threatening disease, they can significantly improve patients’ ability to live their lives.
- K Boyd, “What Is Retinitis Pigmentosa?”, American Academy of Ophthalmology (2021). Available at: https://bit.ly/retpig.
- WHO, “World Report on Vision”, World Health Organization (2019). Available at: https://bit.ly/wrov-who.
- The Business Research Company, “Cell and Gene Therapy Global Market Report 2022: By Product, By Application, By End-User,” The Business Research Company (2022). Available at: https://bit.ly/3Jp2IKH
- Fighting Blindness, “Inherited Retinal Diseases Cost the US and Canadian Economies up to $33 Billion Annually”, Fighting Blindness (2020). Available at: https://bit.ly/ret33bill
- Retina International, “IRDCOUNTS: The Cost to Wellbeing when living with an IRD,” (2021). Available at: https://bit.ly/3Pe7lJu.