Why isn’t there a cure for Parkinson’s?
A cure means different things to different people, but what we can be certain of is that we don’t yet have one for Parkinson’s.
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Charities these days are all promising their research will lead to a cure, but while humanity has eradicated, or is on the way towards eradicating, some infectious diseases — such as small pox, measles and polio — it is unlikely that we will ever see a day when humans do not get cancer, heart disease or neurological conditions like Parkinson’s.
What is a cure?
But the world cure doesn’t necessarily mean eradication. The Oxford English Dictionary provides the following…
Cure: Relieve (a person or animal) of the symptoms of a disease or condition synonyms: heal, restore to health, make well, make better, restore, rehabilitate, treat successfully;
The word originates from the Latin words curare ‘take care of’ and cura ‘care’. As a noun, cura originally encompassed care, concern and responsibility. It wasn’t until Middle English( c. 1150 to c. 1470) that the terms ‘medical care’ and ‘successful medical treatment’ arose and the word cure started to focus on using medicine to tackle symptoms.
Towards effective treatment
Today, the word cure does mean different things in the context of different conditions. Successful medical treatment that relieves symptoms involves distinct strategies depending on the condition. Treatment may aim to remove the underlying problem completely, reverse the damage that has been done or manage symptoms such that they do not impact on quality and length of life.
Effective treatment may involve anything from medication to therapy, exercise to diet. For instance, when caught early, heart disease can be reversed through exercise, type 2 diabetes can be forced into remission with diet, infections can be eradicated with medications and even prostate cancer can be effectively managed so that the majority of men will survive this type of cancer.
But for Parkinson’s, and other neurological conditions like dementia, most of the time it is not possible currently to eradicate the condition, reverse the damage that has been done, or even stop the symptoms from becoming more severe with time — really the effectiveness of the treatments we have is somewhat limited.
So, why is finding a cure so difficult?
In the 1960s, when levodopa was first discovered, it was heralded as a cure for Parkinson’s. Researchers had identified that Parkinson’s symptoms were due to a lack of dopamine in the brain and had discovered a treatment that replaces this missing chemical messenger. For the first time, they had a drug with the ability to reduce and relieve symptoms of the condition. Today, levodopa is still the gold standard for Parkinson’s treatment. When it comes to effective medical treatment it is actually very good, particularly in the early stages.
However, no current Parkinson’s medication could be called a cure. Despite numerous improvements that have been made over the last 50 years, which make these drugs more effective and longer lasting, in the long term, these medications fail to completely relieve the symptoms of Parkinson’s. The condition continues to have an ever-increasing impact on quality of life and, for many of the 145,000 people in the UK with Parkinson’s, is a battle that is fought every day. Additionally, there are many symptoms, particularly non-motor symptoms like sleep problems, anxiety and pain, that are not adequately controlled by any medication. And these too progress as the condition becomes more severe.
The reason for the progression of symptoms stems from the ongoing loss of brain cells. At the moment we cannot slow the course of cell loss in Parkinson’s, and at the point of diagnosis around half the dopamine-producing brain cells of the substantia nigra may have already been lost. Levodopa and other Parkinson’s drugs, such as dopamine agonists, aim to replace or mimic the action of dopamine in the brain to mask the symptom. But as more cells are lost, more drugs are needed to combat this loss — and the side effects of these medications start to impact dramatically on quality of life.
When it comes to slowing Parkinson’s, we can slow the progression of symptoms with exercise, but research has yet to provide a treatment that stops further damage to the brain. But the reasons why are actually quite simple, and can be overcome.
The top 5 reasons there is no cure for Parkinson’s
1. We don’t fully understand the causes.
If we are to design a treatment that stops the condition at its source we really need to know why brain cell death happens in the first place.
In history, blind luck has led scientists to stumble upon effective treatments for conditions like smallpox and infections that are responsive to penicillin. But for a condition as complex as Parkinson’s we should invest in research that fills in our incomplete view of what is happening inside the brain as it will give us the best chance of developing treatments that tackle the underlying causes of brain cell loss. Fortunately, there are some extremely talented and dedicated researchers, working with cutting-edge science and technology, trying to better understand Parkinson’s — and they are making new discoveries all the time.
2. We diagnose too late.
The trick to effectively treating the vast majority of human conditions is early identification. The idea is to intervene before too much damage has been done and use treatments that tackle the source of the problem. This is not only important for the quality of treatment it also makes finding treatments that slow the condition easier.
Drugs that may slow Parkinson’s will be most effective if they are used in the earliest stages of the condition when there are more healthy brain cells remaining. But diagnosing Parkinson’s, particularly in the early stages, is tricky. What we need is a definitive diagnostic test that is accurate in the earliest stages of the condition. This test may also help with another problem — the fact that we also have trouble measuring the progression of Parkinson’s. It may seem trivial but if you wish to demonstrate a new treatment slows progression, one of the things you need to do to is measure if progression has actually slowed.
A test for Parkinson’s would be based on a measurable change in the body, known as a biomarker. Researchers are starting to make headway towards finding a biomarker that is sensitive and accurate enough to diagnose Parkinson’s, and are interested in detecting changes in a variety of ways from brain scans to blood tests, and even breath analysis. We’re funding research in this area so that one day that will be able to definitively diagnose, accurately monitor and even predict Parkinson’s because all this will help us develop a cure.
3. It’s not just one condition, there are multiple types of Parkinson’s.
Like cancer, we are starting to understand the importance of subtyping Parkinson’s and developing tailored treatments that will be more successful than a one size fits all approach. Better understanding is coming from large scale studies that follow vast numbers of people with the condition over time. And we are starting to see how the subtypes of Parkinson’s have different symptoms, progression rates and even different responses to medication.
To effectively treat Parkinson’s, we probably need to tackle each of these subtypes differently, providing the right treatments and support to suit the individual and their form of Parkinson’s. And this starts with understanding more about how we classify and identify these different types.
You can read more about research into personalised treatments in our recent blog ‘Precision medicine for Parkinson’s, how close are we?’
4. Clinical trials often fail.
Did you know up to 10% of people taking part in clinical trials into early Parkinson’s may not actually have the condition. And because they won’t benefit from the treatment they are likely affecting results even leading to the failure of these trials.
Fortunately, through initiatives like the Critical Path for Parkinson’s, we’re leading the way towards better clinical trials that are more likely to succeed.
Today, we are starting to identify what may be behind the loss of brain cells, and clinical trials are underway to try and tackle everything from the build up of alpha-synuclein to inflammation. But, without effective clinical trials, we risk failure simply because we are not testing treatments in the right way.
You can read more about the problem of clinical trials in Parkinson's and the solution in this blog.
5. There isn’t enough investment in Parkinson’s.
Over that last few decades there have been a number of large scale clinical trials for Parkinson’s that have failed at the final hurdle. These disappointments have led some companies to redirect their investment into other research areas, which may be perceived to be lower risk and potentially more profitable. Without investment promising ideas start to pile up on shelves with no opportunity to move forward, and progression towards better treatments slows and eventually stalls.
There are promising scientific discoveries for Parkinson’s that are not being picked up and developed by commercial companies. We believe we can step in here to bring new treatments forward faster. Through our Parkinson’s Virtual Biotech we’re acting in a similar way to a small biotech company. However, unlike a commercial company, we are dedicated to developing new treatments for one condition — Parkinson’s, and doing so as quickly as possible.
How far have we come?
By addressing the underlying problems that led to the loss of cells, we believe it is possible to develop new treatments that slow the progression of Parkinson’s. These treatments, combined with research into cell based therapies that may one day be able to reverse the loss of cells, and current therapies that help to relieve symptoms could together be an effective cure.
There are only a few examples in history where a single approach has provided a cure for everyone with a condition, and Parkinson’s will be no different. It will involve different treatments and therapies at different times for different people. But the multiple pieces of this puzzle are starting to come together, and we are starting to make breakthroughs that could relieve symptoms for the rest of life.
Parkinson’s is a progressive neurological condition that affects about 145,000 people in the UK and an estimated 7–14 million people worldwide. There is currently no cure, and we desperately need better treatments.
You can help us speed up the development of new and better treatments, and a cure for Parkinson’s by donating to groundbreaking research today.
