The Parkinson’s Drug Trial: A Miracle Cure?

I’m sure many of you have seen the programme about a landmark Parkinson’s study, that was aired on the BBC last night (28^th February 2019). It is a very well-produced fly-on-the-wall documentary that follows the investigators, inventors and some participants that have pioneered a truly ‘disruptive’ trial. If you haven’t seen it, stop reading and watch now (UK readers only).

The inimitable Tom Isaacs, who was one of the first patients into the study, and who's charity the Cure Parkinson's Trust funded this study.

What made it so unique – after all, there are thousands of drug studies that take place across the UK every day. Usually a study is designed to test one thing – most often a drug. In this study, they didn’t just test if the new drug worked. They had to invent new hardware – that needed to be tested. They had to invent a new kind of brain surgery – that needed to be tested. They had to persuade fairly risk-averse regulatory bodies and ethics panels that doing all three, together, at once was fair, safe and acceptable. Regardless of the outcomes of the study, I can only marvel at the courage and dedication shown by every person involved, from the chief investigator and the whole study team, to each and every participant and their families. Medicine usually progresses by small evolution, this study was a major revolution.

So what did the study show? ***Spoiler alert*** (The second part of the documentary is due to be aired next week. Here I will review the peer-reviewed scientific data that was published in two papers this year)

The one sentence summary from the first paper might, on the surface, appear to indicate defeat, “At the 40-week point, however, we have not shown clinical benefit despite this putamen-wide tissue engagement.” However, despite the headline ‘failure’, there is so much to celebrate.

Firstly, the managed to recruit (in fact, for 42 study ‘spots’, they had over 200 people volunteer). This is no small challenge, especially when there is the very real risk of making people worse off, and asking people with Parkinson’s to travel to Bristol every month for nearly a year.

Secondly, they proved that the hardware and surgery worked, and worked safely. 

Image from BBC.com

Thirdly, and very importantly, they showed that after 40 weeks, there was no change in the dopamine-scan in those who’d had placebo; but in the GDNF group there was a marked change that took the appearances back to those expected at the early stage of Parkinson’s. Bear in mind that on average, the participants had had symptoms of Parkinson’s for over 10 years, and in some for well over 15 years!

Fourthly, at the end of 40 weeks, no patients in the placebo group had movement scores that improved by 10 or more points. However, 9 out of the 17 participants given GDNF improved by between 10 and 16 points. This was not only statistically significant (albeit as a post hoc analysis), but most definitely clinically significant.

So what else can be said? Well, firstly, there was a very strong placebo effect. At one point in the film, the mother of one of the participants says, “To have a huge operation like that, and then have to have a placebo. Is that human? Not really, is it!” The BBC have produced a very good summary on the placebo (and nocebo) effects. The fact that the placebo group did improve so much, means that there is much less of a difference between the two groups. This doesn’t necessarily mean that the GDNF didn’t work, it means that the effect is ‘lost’ in the statistical analysis. 

Furthermore, the numbers in the study were very small, with only 41 patients in total, (21 GDNF, 20 placebo.) This further reduces the chance of finding statistical differences.

A - model showing the novel equipment that was designed and made specifically for this study. B - the port that participants lived with, with which they were 'hooked up' to treatment. C - brain scan showing that the drug delivery worked exactly where it needed to. D - patient sat being infused with treatment via the 'head port'. E - A (not-so) ordinary infusion suite. (image from linked Brain paper)

After the original 40 week study, both groups continued to get another 40 weeks treatment, this time with everyone getting the GDNF. At the end of this phase, there was still no overall group differences from the very beginning to the very end between those who had 80 weeks vs 40 weeks of GDNF treatment, in terms of the movement scores off all treatment. However, those who’d had GDNF all along had fewer increases in their regular medication (to a tune of nearly 5 tablets-worth per day (59mg vs 289mg)). There was also ongoing improvement in the ability to do daily activities in those having GDNF for 80 weeks, and a continued improvement in the proportion of the day when the medication was working well.

There are several other factors that need to be borne in mind. The study cost £3m. Divided over each of the participants amounts to over £73,000 per person. Although this seems like a lot, the actual treatment cost, should this every come to clinical practice would likely be much lower, as it includes all the extra costs associated with running a complex clinical trial. Furthermore, if GDNF is ultimately shown to slow the progression of the condition, if it means that someone maintains their independence and can either carry on working (and paying tax), or stay in their own home independently, rather than take early retirement or move to a nursing home, this really is small change – and when you factor in Quality of Life benefits, must surely be a price worth paying.

Finally (and thank you for bearing with me to this point), all these patients had a diagnosis of Parkinson’s disease for around 8 years. This means that they had the pathology for approaching 20 years. Many were profoundly affected by their symptoms. To use a metaphor I’ve used previously on this blog, it is easier to blow out a match than fight a forest fire. The brain of someone with advanced Parkinson’s is vastly more effected than at the early, or even pre-symptomatic stages. Any restorative attempts are far more likely to work if you can catch it early and intervene early. This is the overwhelming conclusion from treating infections and the whole concept of cancer treatment. 

Hopefully, you and your friends will help us reach that goal with Parkinson’s. You can do your bit by helping us to identify the very earliest phase of Parkinson’s: www.predictpd.com. Taking part involves 25 minutes in front of your own computer at home, and certainly doesn’t pose any of the risks that this study did!

As a final note, I would like to say that this programme reminded me how much of a privilege it is to look after people with Parkinson’s in the clinics of the Royal Free and Luton & Dunstable Hospital; how much of a privilege it is to be at the forefront of Parkinson’s research, funded by Parkinson’s UK, and how much this motivates me while training for the London Landmarks half-marathon and Virgin Money London Marathon.

RNR 

Great Debates

While there are many great debates happening this week in the UK, perhaps the most interesting happened at today’s biannual meeting of the Association of British Neurologists Movement Disorders Special Interest Group, held in the beautiful Oxford Town Hall. The opening session of the meeting was a debate between two giants of the international Parkinson’s world: Professor Donald Grosset from Glasgow, and Professor Ron Postuma from Montreal.

The topic they were debating was “Should research focus on prodromal disease prevention or improving symptomatic therapies?” Professor Grosset set out the reasons for focussing on better treatments in the complex phase of the disease – when the treatments that we have either fail to work or side effects become increasingly troublesome and diffucult to manage. He also pointed out the near-total lack of well-proven treatments for many of the non-motor aspects of Parkinson’s (a point we have laboured in previous blog posts here). He suggested that detection of the prodromal stage was hit-and-miss and that the best case scenario was that trials in this group would costs hundreds of millions of pounds which would be better served investing in treatments for people with definite Parkinson’s.

Ron Postuma countered his argument and opened with the metaphor central to preventive medicine: people are falling over a waterfall and nearly drowning in the pool below. A man is pulling them out one by one and calls to a bystander to help. The bystander walks away, but returns at the top of the waterfall to stop people from falling down in the first place. Although  this metaphor may seem simplistic, it highlights the importance of focussing on the earliest stages. He went on to simplify the drug treatment of established Parkinson’s as “playing with neurotransmitters” – and no matter how successful one might be at doing that, there is an underlying progression of brain death. To deal with that means to effect a change before disease causing cascade of events has become unstoppable – i.e. in the earliest (prodromal) stages. Finally, he highlighted the seismic changes that have occurred in medicine in the last two generations. Penicillin used to be so expensive that patients given penicillin had their urine collected, the excreted penicillin extracted and given back to the patients to make each vial go further. Wards for women with infected wombs after miscarriages who would almost inevitably succumb to their infections closed within weeks. The AIDS wards that were in most hospitals in the 70s and 80s were empty just a few years after HIV medication started being used. New treatments for advanced cancer have changed the landscape for some of these diseases (including nilotonib which is currently being trialed in Parkinson’s), and the last two years has brought these game-changing experiences to neurological diseases with drugs such as Nucinercin – effectively curing an incurable genetic condition that killed children in their first few years. The message, he said, was clear – things we now take for granted were once hard and very expensive, and for Parkinson’s there is change on the horizon.

The rest of the meeting continued with many other fascinating and useful talks from some of the leaders of British neurology, and has offered many insights and ideas that we at Predict-PD can use to help bring us closer to a robust identificaiton of prodromal Prkinson’s and therefore, another step closer to a cure.

RNR

The prodromes of Parkinson's

Following on nicely from our last post, we are delighted to publicise our latest peer-reviewed publication.

This will come out in a special edition of the European Journal of Neuroscience, dedicated to the memory of Tom Isaacs. Tom was the founder and leader of the Cure Parkinson's Trust - a truly dynamic leader and a real disruptive presence (in all the right ways) within  Parkinson's research. We are honoured to have our names and our ideas as testimonial to him in this way.

It is clear that Parkinson's is more of an umbrella condition than one single entity. For instance, some people have significant tremor, while others have none. Some progress very slowly, and a decade from diagnosis have barely any more symptoms - others progress more quickly. For many Parkinson's affects mainly movement while others have many non-motor symptoms. It is likely (although not yet proven) that these different subtypes of Parkinson's have a different underlying process causing them.

It therefore stands to reason that the earliest phases are also different. In our article we lay out the evidence that Parkinson's that comes from people with a particular kind of sleep disorder (REM sleep behavioural disorder), smell loss, and genetic forms do all look different. The evidence is not bomb-proof, but in Predict-PD we will be able to shed light on both the sleep disorder, smell loss and try and pick apart differences in the general population.

To see the article, please see the journal website. Please also remember to talk to friends and family to read more about the study and sign up themselves: www.predictpd.com

RNR

Why more Parkinson's might not be such a bad thing

This week, the Lancet Neurology have published the "Global, regional, and national burden of Parkinson’s disease, 1990–2016: a systematic analysis for the Global Burden of Disease Study 2016", a very large and very complex analysis of the amount of Parkinson's all over the world.

As can be seen from the map below, there are huge differences in the rate of Parkinson's. Some of the reasons for this are clear, and some are less well understood.

Worldwide rates of people with Parkinson's (age-standardised prevalence per 100,000 population in 2016)

What is more interesting is the rates of change. Parkinson’s was the fastest growing condition in terms of prevalence, disability and death of all neurological conditions. Since 1990, the prevalence (number of people with a condition), mortality, and disability-adjusted life-years (One DALY can be thought of as one lost year of "healthy" life. Read more about DALYs here), have more than doubled. In part this is because of the population of the world getting older. This figure shows the rates of Parkinson’s for men and women at different ages.

The percentage of men (red) and women (blue) with Parkinson's by age. The line is  the current estimate, with the shaded area being the region of uncertainty in which the 'true' figure lies.

Although there are many reasons why this increase is being seen, one reason is that the prevalence is related to two things: how many people receive a new diagnosis, but also how long people with a condition live with it. If the rate of new diagnoses has not significantly changed (the evidence remains unclear), in a generation we have enabled people with Parkinson’s to live longer. The authors remind us that this is only partly due to drugs like levodopa, and also due to the general increase in sanitation, food security, general health improvement, vaccination etc. as well as attention to things like physiotherapy, speech and language therapy etc.

So as we go forward, lets hope that the number of people with Parkinson’s continues to increase, but the DALYs decrease. And lets continue to work hard so we can at last make a real change to the incidence of Parkinson’s.

RNR

GBD 2016 Parkinson's Disease Collaborators. Global, regional, and national burden of Parkinson's disease, 1990-2016: a systematic analysis for the Global Burden of Disease Study 2016. The Lancet Neurology. 2018 Oct 1;17(11):939–53. 

To boldly go

An article on the BBC news website has prompted me to write a post that I’ve been considering for a while. 

Billy Connolly, the edgy and flamboyant comedian, has been an outspoken supporter of research for a cure for Parkinson’s. He was diagnosed with the condition five years ago. This week he has publicised that he is willing to be a ‘guinea pig’ for a stem cell trial.

Irony, foreshadowing or mere coincidence?
Picture from http://bit.ly/SundayPost100

I have been asked about my 'stance' on stem cell treatments for Parkinson's in clinic, and I confess to not having a 'stance'. The reason for this is that the state of the science is truly in its infancy, certainly in terms of deliverables for people with Parkinson's. This is not to diminish the decades of work that have led us to where we are, but even heroic gestures, such as Connolly's will only inch us forward in the marathon that lies between now and the New Era of stem cell treatments.

In preparation for this blog post I have read an update from the recently established GForce-PD network: a network of researchers from around the world who are working together to bring stem cell treatment closer to reality. An excellent (technically written) history of the subject can be found in a Nature Reviews article written by Prof Roger Barker from Cambridge.

Landmarks in the history of stem cell treatment of Parkinson's.
From Nat. Rev. Neurol.doi:10.1038/nrneurol.2015.123

As a brief overview, stem cells can be derived from a 'matched-donor' - in a similar way to  how organ donation works currently; from embryos, which has both ethical and immunological issues; and from the individual themselves.

Different sources of stem cells
from https://doi.org/10.1016/j.stem.2017.09.014

They are then surgically implanted into the area of the brain that is most affected by Parkinson's, where they grow and develop into (hopefully) fully functioning dopamine-producing cells. In essence, the aim is not just to mask the symptoms like current treatments do, but return the individual's brain to how it would be functioning without Parkinson's.

I want to focus attention on one aspect of the discussions of this group as it has particular resonance with PREDICT-PD. There is a very difficult decision regarding whom to choose as participants in a trial of stem-cell treatment. Do you choose participants who've only recently been diagnosed, or do you choose people in later stages of the condition?

Some arguments for 'earlier' intervention is that these individuals will be physically fitter so at less risk of the initial surgery, and be better able to tolerate the immunosuppression required. They would also have longer to reap the benefits of their investment, and given that this kind of intervention would be at great financial cost to a health system, the payer (be that the NHS or any other health system) would get the best bang for its buck.

However, these arguments only hold water on the assumption that it works. The flip side of the coin also applies. A big fear of stem cell technology from the early days of the field, is that the new cells go outside the normal control systems of cells and develop into cancer cells. This might prove worse for someone that the slow progress of Parkinson's left untreated by stem cells. The immunosuppression also has long term risks, with unusual infections, or usual infections presenting in unusual ways. 

What about the other option? Individuals with more advanced disease have more physically measurable symptoms, and so less time is needed for a (very expensive) clinical trial to show differences between treated and untreated (or sham procedures). Given the risks outlined above, it could be conceived that stem cell treatment is a 'last-chance saloon' treatment that should be embarked on only where more established treatments have failed. We have written about the personal costs Parkinson's on this blog, and that as the condition advances the costs spiral. If stem cell treatment is withheld until later in the condition, there is a greater chance that the cost will be offset by savings in other areas, as the need for more help reduces with a return of independence in multiple areas.

There are no perfect answers. It is essential that a global effort is sustained to get us safely, ethically and rigorously through the choppy waters that lie between now and a time when stem-cell treatments are as commonplace as other treatments for Parkinson's.

RNR

Parkinson's ex machina

Last week Anna talked about the need to ensure the 'human' is kept at the centre of drug design for Parkinson's treatments - "focussing on human cells, tissues and subjects". Today I also want to discuss the role of humans in Parkinson's and the role of machines.

Neurology (and neurologists) take pride from being a bastion of clinical medicine - the heart and soul of our practice is listening to our patient and observing their every movement. In some ways neurology has not moved on much (in spirit) from the historic view of 'physicians' portrayed so poignantly by Sir Luke Fields. Movement disorders, and the diagnosis and management of Parkinson's are perfect examples of this human approach, with no equipment other than a tendon hammer necessary to make the diagnosis.

taken from https://www.tate.org.uk/art/artworks/fildes-the-doctor-n01522 with thanks

However, today's world has moved on leaps and bounds, and medicine and neurology are desperately trying to keep pace. In the 130 years since this scene was painted, our world has changed almost unrecognisably (although a Google image search of 'doctor' would make anyone believe that it is still delivered primarily by middle aged white men - which thankfully is less true now than ever).

It is old hat to say that technology continues at a blistering pace. Miniaturisation  has made yesterday's science fiction into the everyday. 'The Fantastic Voyage' described a vessel that was shrunk and inserted into a person's body to save them - well thrombectomy for stroke, stunting for heart attacks, and a video camera so small you can swallow it to get diagnostic pictures throughout the gut are all in routine clinical practice in the NHS today.

The Fantastic Voyage (1966) - picture from https://www.britannica.com/topic/Fantastic-Voyage

High street technology has revolutionised our lives. There is more processing power in my 4 year old iPhone than Armstrong, Aldrin and Collins had on Apollo 11. There is now an enormous market in wearable technology that will give you a beat-by-beat analysis of your heart rate, count your steps in a day, your calorie output, measure your power in watts on a bike, feet climbed on the stairs and just about any other metric you can imagine.

Just a small number of the dizzying array of activity tracking watches available on the high street (picture from  Groupon.co.uk)

All this brings me onto a review I have read, "Optimizing clinical assessments in Parkinson's disease through the use of wearable sensors and data driven modelling"

The article offers a review on some of the hardware software and statistical approaches to understanding the data. At its heart is the understanding that a neurologist sees their patient for perhaps 3 or 4 15-20 appointments in a year. That clearly leaves 8,759 hours per year where the neurologist has no ability to observe their patient move. Wearable technology brings us a (relatively) non-intrusive window into the 'real lives' of our patients. With the vast amounts of data that this can bring, we need very sophisticated algorithms to understand it, and we need to understand the computer science and mathematical constructs that underlie those algorithms.

Going further than mere observation is prediction - the holy grail in healthcare, and our clearly stated aim in PREDICT-PD. This article concludes by cautioning us about the variation in quality and output of this technology, but offering us the hope that these devices and underlying data analysis will improve clinical decision making, provide more personalised care, and better understand and highlight the differences in the manifestations of what we currently call 'Parkinson's disease', leading to better trials, treatments and one day - cure.

RNR

News from the Land of Milk and Honey

I had the good fortune to attend a conference on Precision Medicine and Ageing today. This brought some of the leading scientists from the UK and Israel together, as part of the British Council’s Britain Israel Science and Innovation Network. The day included speakers talking about the latest breakthroughs in genomics, neuroscience, cellular biology and many other fields of scientific endeavour and how they relate to the biology of ageing (in health as well as disease) and how these breakthroughs are bringing us closer to the ‘promised land’ of Personalised, or Precision medicine.

The talk that I found the most interesting came from Dr Maya Leventer-Roberts, from the Clalit Research Institute. This is not a university department, but the in-house research arm of the largest of Israels four health providers. They have an unparallelled treasure-trove of health data. She explained that all Israeli citizens belong to one of these four organisations who provide all aspects of care: GP, pharmacy, testing laboratories, hospitals – you name it. What’s more, very few people change providers, so they have a well-coded database of people’s wellness, illness and health behaviour at all stages of life.

I have since found a paper from last year which uses some of their data to examine a relatively neglected aspect of Parkinson’s – depression. Unfortunatley a huge proportion of people with Parkinson’s struggle with depression. We also know that late onset depression is a risk factor for Parkinson’s. 

In this study, they looked at mortality rates in Parkinson’s and the association with how adherent people were with antidepressents. They analysed the data of 10,000 people with a diagnosis of Parkinson’s as well as at least one prescription of an antidepressant. They then categorised people into how frequently they tookthe antidepressants by comparing their prescriptions from the doctor with the number of purchases of antidepressants from the pharmacies. Finally they looked at death by any cause over the 4 year study period.

They found that the people who had Parkinson’s and depression who took their antidepressants the least were 43% more likely to die within the 4 year period, compared to those who took it the most regularly. The increased mortality was exacerbated by having an increasing number of other medical problems.

I must stress the old adage: association does not equal causation. This kind of retrospective observational study cannot provethat one thing causes another. However, it is an important reminder that depression is an important aspect of Parkinson’s, and that poorly managed depression is associated with increased mortality. It also reminds me that older people, with Parkinson’s, depression and perhaps four or five other medical conditions may be on 15-20 or more tablets a day. What can I do as a clinician to help them remember what each is for, and why each is important to take? What can we do as a society to help people with depression with both drug and non-drug treatment options? How can we better prepare ourselves, individually and societally, for ageing and the only true inevitability of life?

RNR

Shoval G, Stubbs B, Balicer RD, Feldman B, Hoshen M, Zalsman G, et al. 

Low adherence to antidepressants is associated with increased mortality in Parkinson disease patients. 

Parkinsonism Relat Disord. 2017 Oct;43:92–6.

INTRODUCTION:The purpose of this study was to evaluate the relationship between adherence to antidepressants (AD) and all-cause mortality in a population-based cohort of patients with Parkinson's Disease (PD).

METHODS:From a database of more than 4 million people, 8553 patients with PD who purchased an AD at least once between the years 2008-2011 were retrospectively followed for all-cause mortality over 4-years. Adherence was measured as a ratio between dispensed and prescribed durations and was modeled as: non-adherence (<20%, n = 1566), poor (20%-50%, n = 1184), moderate (50%-80%, n = 1584), and good (>80%, n = 4219) adherence. Multivariable survival analyses adjusted for demographic and clinical variables including physical comorbidities known to influence mortality were conducted, however there was no adjustment for other psychiatric disorders and medications.

RESULTS:Unadjusted mortality rates were 20.4%, 25.1%, 23.4% and 25.6% in those classified as non-adherent, poor, moderate and good adherence respectively (χ2 = 18.45, p < 0.0001). The non-adherent and poor adherence groups had significantly increased adjusted mortality hazard ratios (HR) of 1.43 (CI: 1.26-1.62) and 1.26 (CI: 1.1-1.44) respectively compared to the good adherence group. Using the same model, the adjusted HR for death among males was 1.49 [95% CI: 1.36-1.62] compared to females. People with PD and Charslon's Comorbidity Index score of 3-4 (HR 1.3, P < 0.001) and 5+ (HR 1.78, P < 0.001) were more likely to die than those with 0-2 comorbidities.

CONCLUSIONS:Our findings suggest that poor adherence to AD is associated with increased all-cause mortality in people with PD. Given the high prevalence of depression and AD effectiveness, efforts to promote adherence should be prioritized in clinical practice.

Remedies from the natural world

An article caught my eye this week as several comments received on this blog and in clinic relate to ‘natural’ remedies for Parkinson’s. To provide some background, my therapeutic philosophy is a common one: I will only prescribe or endorse treatments that have gone through robust, unbiased, reproducible testing, and where the benefits outweight the risks. I also believe that there are undoubtedly treatments that have the power to radically alter diseases that are under our noses in the natural world, and once they are identified, purified and tested, will revolutionise medicine. Exenatide is a perfect example: originally derived from the saliva of the Gila monster, this is now a powerful drug against diabetes and may even have the ability to halt or slow Parkinson’s. 

This article looks at whether blackberry juice can reduce levodopa-induced dyskinesia. The first thing to point out was that they didn’t test it in humans with Parkinson’s disease, this experiment involved the MPTP mouse model of Parkinson’s. Mice were given the same amount of levodopa and then different groups were given increasing doses of blackberry juice. The good news is that there was some benefit on the extra movements associated with ‘dopamine overdose’. However, this was mainly seen in the 15mL/kg group. To put this into a human context (assuming that it works as well in humans with Parkinson’s as mice with MPTP induced parkinsonism, which is a very  big assumption, a human would have to drink over a litre of pure blackberry juice per day to have less dyskinesia. 

Science is a journey of increments. These positive results may yield a useful weapon for people with Parkinson’s, but plenty of work needs to be done. I highly recommend blackberries, especially ones forraged on a nice walk in the woods, but I wouldn’t suggest they’re going to make your Parkinson’s better just yet.

RNR

Effects of blackberry (Morus nigra) fruit juice on levodopa-induced dyskinesia in a mice model of Parkinson's disease.

Fahimi Z¹, Jahromy MH¹.

J Exp Pharmacol. 2018 Jul 4;10:29-35. doi: 10.2147/JEP.S161782. eCollection 2018.

Abstract

BACKGROUND AND OBJECTIVE: 

Levodopa-induced dyskinesia (LID) is a movement disorder that occurs due to levodopa consumption for a long period to attenuate Parkinsonism. Plants have been the basis for medical treatments in human history and still widely practiced. Blackberry (Morus nigra) is one of the fruits rich in anthocyanin. The present study examined the effect of blackberry fruit juice on LID in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinson's disease in mice.

MATERIALS AND METHODS: 

In this study, 42 male mice were used, which were divided into six groups equally: one control group and five groups receiving MPTP injection. After confirmation of Parkinsonism in MPTP groups, one group was preserved without treatment and four other groups were treated with levodopa (50 mg/kg ip). After the onset of LID (2 weeks), one group was kept without additional treatment and three other groups were treated with three different doses of blackberry fruit juice (5, 10, and 15 mL/kg) with levodopa orally for 7 days. Abnormal involuntary movement scale (AIMS) and cylinder behavioral test were carried out according to the schedule. The collected data were analyzed using the SPSS software with the significant level of P<0.05.

RESULTS: 

Parkinson's disease was confirmed with AIMS test on the fourth day after MPTP injection. The onset of LID was observed after 2 weeks of levodopa treatment using both behavioral tests. The result of administration of M. nigra fruit juice for 1 week showed that this addition is useful in hindering LID. These effects were more pronounced at doses 10 and 15 mL/kg with nearly the same results on attenuating AIMS. Low dose of the fruit juice does not seem to affect LID significantly.

CONCLUSION: 

M. nigra fruit juice is effective to attenuate LID in an MPTP-induced Parkinson mice model.

Is the horizon getting closer ?

Week after week we talk about the need for a disease modifying drug in Parkinson’s, and week after week we hope to reassure you, dear reader, (as well as ourselves) that this Holy Grail is getting ever closer. 

This week marks the publication of a study that may mark a turning point in this journey. Prothena Pharmeceuticals have run a study looking at the safety and tolerability of a new compound (excitingly called PRX002/RG7935). This is a compound that sticks to the toxic protein that is understood to cause the brain cell loss in Parkinson’s – α-synuclein. Once it sticks to this substance, it ‘flags’ the body’s immune system to come and clear up the mess. This, we think, reduces the amount of the α-synuclein that is floating around and causing damage. 

In this study 80 participants with mild-moderate Parkinson’s were given one of six different doses of this medicine or salt-water (placebo) through a ‘drip’. They attended once a month and the infusion lasted 1-2 hours. Neither the participants nor the investigators knew how much (if any) of the drug they were getting. They received three infusions in total.

I must stress that this study wasn’t designed to see if this did anything at all for their Parkinson’s. The study was too small, and too short for any changes to be detected. The primary purpose of this study was to evalute whether the medicine was safe and tolderable, with secondary objectives of studying what happens to the drug when it is in the body.

Overall, of the 55 participants that had any strength of the medicine, 50 completed the study, and 5 did not manage all 24 weeks of the study. 1 stopped because their Parkinson’s worsened, 1 decided to withdraw (reason not stated), 2 (both in the highest dose group) stopped because of side effects, and 1 also in the highest group withdrew. I also note that 3 out of 25 getting placebo also withdrew.

This study is a vital step. After extensive laboratory testing, a compound like this will be given to a very small number of totally healthy volunteers to ensure it is safe in humans. Then it will be given to a small number of volunteers with the condition to make sure it is safe in the ‘target’ population and to determine a range of safe doses, which is this study. Then it will be given to a moderately large sample to see if there are any suggestions of positive effects and to refine the ideal dose, and finally it will undergo a large study of affected individuals where the investigators (and cruicially the funders) hope to find that it has a true benefit.

All the participants in this study had had Parkinson’s for around 3 years (although this was as much as 15 years) and was moderately advanced. We hope that in future studies, the investigators take people with the earliest possible disease duration and learn lessions from the Alzheimer’s journey. 

This compound has been being studied in the earliest stages of the research process for around 10 years. The next stage of the path for this compound, the PASADENA trial, started almost exactly 1 year ago, and will be running until February 2021. I would expect results to come out towards the end of 2021, and then (hopefully) a phase 3 study will start which will take several more years to run and analyse. If all these steps are successful, we may be in a position to prescribe this medication in around 7-10 years from now.

RNR

Safety and Tolerability of Multiple Ascending Doses of PRX002/RG7935, an Anti-α-Synuclein Monoclonal Antibody, in Patients With Parkinson Disease: A Randomized Clinical Trial.

JAMA Neurol. Published online June 18, 2018. doi:10.1001/jamaneurol.2018.1487

Joseph Jankovic, MD; Ira Goodman, MD; Beth Safirstein, MD; Tonya K. Marmon, DrPH; Dale B. Schenk, PhD; Martin Koller, MD, MPH; Wagner Zago, PhD; Daniel K. Ness, DVM, PhD; Sue G. Griffith, MD, PhD, MRCP; Michael Grundman, MD, MPH; Jay Soto, BS; Susanne Ostrowitzki, MD, PhD;Frank G. Boess, PhD; Meret Martin-Facklam, PhD; Joseph F. Quinn, MD; Stuart H. Isaacson, MD; Omid Omidvar, MD; Aaron Ellenbogen, DO;Gene G. Kinney, PhD

Importance:Aggregated α-synuclein is believed to be central to the pathogenesis of Parkinson disease (PD). PRX002/RG7935 (PRX002) is a humanized monoclonal antibody designed to target aggregated forms of α-synuclein, thereby inhibiting neuron-to-neuron transfer of presumed pathogenic forms of α-synuclein, potentially resulting in neuronal protection and slowing disease progression.

Objective:To evaluate the safety and tolerability of multiple intravenous infusions of PRX002 in patients with idiopathic PD.

Design, Setting, and Participants:Multicenter, randomized, double-blind, placebo-controlled, multiple ascending-dose trial at 8 US study centers from July 2014 to September 2016. Eligible participants were aged 40 to 80 years with mild to moderate idiopathic PD (Hoehn and Yahr stages 1-3).

Interventions:Participants were enrolled into 6 ascending-dose cohorts and randomly assigned to receive PRX002 (0.3 mg/kg, 1.0 mg/kg, 3.0 mg/kg, 10 mg/kg, 30 mg/kg, or 60 mg/kg) or placebo. Participants received 3 intravenous infusions every 4 weeks of PRX002 or placebo and were monitored during a 24-week observational period.

Main Outcomes and Measures:Safety and tolerability assessments included physical and neurological examinations, laboratory tests, vital signs, and adverse events. Pharmacokinetic parameters included maximum PRX002 concentration, area under the curve, and half-life.

Results:Of the 80 participants, most were white (97.5%; n = 78) and male (80%; n = 64); median (SD) age was 58 (8.4) years. PRX002 was generally safe and well tolerated; no serious or severe PRX002-related treatment-emergent adverse events (TEAEs) were reported. The TEAEs experienced by at least 5% of patients receiving PRX002, irrespective of relatedness to study drug, were constipation (9.1%; n = 5), infusion reaction (7.3%; n = 4), diarrhea (5.5%; n = 3), headache (5.5%; n = 3), peripheral edema (5.5%; n = 3), post-lumbar puncture syndrome (5.5%; n = 3), and upper respiratory tract infection (5.5%; n = 3). No antidrug antibodies were detected. Serum PRX002 levels increased in an approximately dose-proportional manner; mean terminal elimination half-life was similar across all doses (10.2 days). Rapid dose- and time-dependent mean reductions from baseline vs placebo in free serum α-synuclein levels of up to 97% were seen after a single infusion at the highest dose (F78,284 = 1.66; P = .002), with similar reductions after 2 additional infusions. Mean cerebrospinal fluid PRX002 concentration increased with PRX002 dose and was approximately 0.3% relative to serum across all dose cohorts.

Conclusions and Relevance:Single and multiple doses of PRX002 were generally safe and well tolerated and resulted in robust binding of peripheral α-synuclein and dose-dependent increases of PRX002 in cerebrospinal fluid, reaching cerebrospinal fluid concentrations that may be expected to engage extracellular aggregated α-synuclein in the brain. Findings support the design of an ongoing phase 2 clinical study (NCT03100149).

Trial Registration:ClinicalTrials.gov Identifier: NCT02157714.

Public Engagement

I had the great honour and privilege to be asked to speak to the Parkinson’s UK Barnet and Brent Branch last night. This was the second time I have had this opportunity to meet and engage with a wonderful group of people.

At PREDICT-PD we are working tirelessly to understand more of the ‘prodromal’, ‘premotor’ or ‘prediagnostic’ stage of Parkinson’s [these are all largely interchangeable terms for the period where Parkinson’s is present in the brain and causing mild, often non-motor symptoms]. However, there is little public or academic conversation about the public ‘appetite’ for moving the point of diagnosis from where it currently sits.

After a brief introduction to the topic, I sat back down, and picked up my notebook and invited the group to engage in a conversation and share some of their thoughts and experiences. I was humbled by the honesty and candour shown by many people with Parkinson’s and their family members.

Some clear themes came out of our conversation:

• ·     Receiving a diagnosis of Parkinson’s is a pivotal moment in a person’s life. As clinicians, the way we offer the diagnosis has a deep and lasting impact that will be remembered, not only by the individual, but by their family for decades. I heard some wonderful stories of good practice, where clinicians had taken their time, been thorough and provided a supportive and accurate diagnosis. Others unfortunately had not been so lucky, and had the diagnosis changed many times or left totally unsupported after a brusque diagnosis. I could only apologise for these experiences. I did also reiterate that Parkinson’s is a clinical diagnosis, with no perfect test in life, and the evidence suggests that even the best experts get the diagnosis wrong 15% of the time.
• ·     So many people last night spoke of the power that comes with acknowledging Parkinson’s, not only to themselves, but to others around them. Telling the ‘tutter’ behind you in the queue at the supermarket that you can’t ‘hurry up’ because you have Parkinson’s changes the shopping trip from being an ordeal to a much more pleasant affair. 
• ·     Family members (and individuals with Parkinson’s) are often relieved by the diagnosis – at last an explanation for all those symptoms, and “at least it wasn’t something else”
• ·     When we discussed the benefits and problems with moving the diagnosis earlier in the disease process, there were not many good things to hear. Too many people suffer at workwith changes to their jobs, reduced hours or even face unemployment as a result of the diagnosis. Others struggle to come to terms with the diagnosis for some time and suffer psychologically, which could be worse if there were fewer symptoms to make it ‘real’.
• ·     However, many saw a positive aspect to learning the diagnosis earlier. This would offer an opportunity start engaging with exercise which has been shown robustly in research and very definitely in the community last night to have a profoundly positive impact on mood, thinking, movement and quality of life. It would also help people make appropriate life decisions, especially regarding work, pension, travel: living the life you want to live regardless of the Parkinson’s.
• ·     When I asked similar questions but in the context of available treatments that change the course of the condition, the group was unanimous: tell us as early as possible!

We left the meeting on a really positive note. There is much excitement in the academic community about how close we are to having truly disease modifying options in Parkinson’s. The road is long, and we still have much work to do: but we’re getting there. I’m delighted that the group last night shared my optimism and excitement.

I was also delighted to share with them (and you, dear reader) this link to Parkinson's TV - an English language version of the amazing Dutch videos created by Prof Bas Bloem's Parkinson'sNET in the Netherlands. Another example of real partnership between people with Parkinson's, researchers and clinicians - answering the questions you have, as well as some that you didn't know you wanted to have!

RNR

Changing Tack

In a very wide ranging and well written review, two leaders of the Parkinson’s field lay down set the terms of engagement and (to mix my combative metaphors), lay down the gauntlet in the quest to find disease modifying treatments.

After defining three kinds of ‘disease modification’ (neuroprotection: preventing the progression of PD; neurorescue: repairing damaged brain cells; neurorestoration: replacing what has been lost), they provide a brief but comprehensive overview of why every attempt so far has failed, from both a mechanistic perspective as well as a methodological perspective.

The key messages to take from this article are thus:

1.     We really need to stop thinking of Parkinson’s as a single condition. As well as many different ways that people experience their Parkinson’s (the different phenotypes), there are also many different molecular and cellular processes. Each person will likely have a different milieu of process that results in their particular phenotype.

2.     Once we can do this, we can start approaching disease modification in a more personalised way. This means recruiting the people with the right kind of Parkinson’s, at the right time, to the right study. We need to become much more sophisticated in the way we study new treatments, probably recruiting very specific groups of participants, for example people with particular genetic changes related to their Parkinson’s, and testing cocktails of treatments, rather than our current blunderbuss approach.

3.     Given that Parkinson’s is a complex, and slowly progressive condition, we must have better progression markers on which to design our studies.

This is going to require a lot of work, with the Parkinson’s population, scientists, clinicians, and industry. In order to get the highly effective treatments that our oncologists have avaiable to them, we need to change the terms of warfare.

What can we all do in the mean time? Pay attention to these three battles. Not necessarily throw the baby out with the bathwater if a particular study doesn’t prove miraculous (which it almost certainly won’t). And if you have Parkinson’s: exercise more!

At PREDICT-PD towers, we strongly believe that identifying the disease earlier, in the prodromal phase, will bring us closer to many of these objectives. Earlier disease is more likely to be simpler disease; it may be possible to identify early phenotypes that map onto particular pathological pathways; we have an opportunity to identify biomarkers that predict the development of established Parkinson’s, thus giving an ideal method of proving efficacy of new treatments.

RNR

Disease modification in Parkinson's Disease: Current approaches, challenges, and future considerations.

Anthony E Lang and Alberto J Espay.

Mov Disord, 2018 vol. 386 p. 896.

http://doi.wiley.com/10.1002/mds.27360

The greatest unmet therapeutic need in Parkinson's disease is the development of treatment that slows the relentless progression of the neurodegenerative process. The concept of "disease modification" encompasses intervention types ranging from those designed to slow the underlying degeneration to treatments directed at regenerating or replacing lost neurons. To date all attempts to develop effective disease-modifying therapy have failed. Many reasons have been proposed for these failures including our rudimentary understanding of disease pathogenesis and the assumption that each targeted mechanisms of disease apply to most patients with the same clinical diagnosis. Here we review all aspects of this broad field including general concepts and past challenges followed by a discussion of treatment approaches under the following 4 categories: (1) α-synuclein, (2) pathogenic mechanisms distinct from α-synuclein (most also potentially triggered by α-synuclein toxicity), (3) non-SNCA genetic subtypes of "PD," and (4) possible disease-modifying interventions not directly influencing the underlying PD pathobiology. We emphasize treatments that are currently under active clinical development and highlight a wide range of important outstanding questions and concerns that will need to be considered to advance the field of disease modification in PD. Critically, it is unknown whether the dysfunctional molecular pathways/organelles amenable to modification occur in a sequential fashion across most clinically affected individuals or manifest differentially in independent molecular subtypes of PD. It is possible that there is no "order of disruption" applicable to most patients but, rather, "type of disruption" applicable to subtypes dependent on unknown factors, including genetic variability and other causes for heterogeneity in PD. Knowing when (early vs late), which (eg, synaptic transmission, endosomal sorting and maturation, lysosomal degradation, mitochondrial biogenesis), and in whom (PD subtype) specific disrupted cell pathways are truly pathogenic versus compensatory or even protective, will be important in considering the use of single or combined ("cocktails") putative disease-modifying therapies to selectively target these processes. Beyond the current phase 2 or 3 studies underway evaluating treatments directed at oxidative stress (inosine), cytosolic Ca2+ (isradipine), iron (deferiprone), and extracellular α-synuclein (passive immunization), and upcoming trials of interventions affecting c-Abl, glucagon-like peptide-1, and glucocerebrosidase, it might be argued that further trials in populations not enriched for the targeted pathogenic process are doomed to repeat the failures of the past. © 2018 International Parkinson and Movement Disorder Society.