Tagged: Prothena

The EMPRSN talk #1

Recently I was invited to speak at the 6th Annual East Midlands Parkinson’s Research Support Network meeting at the Link Hotel, in Loughborough. The group is organised and run by the local Parkinson’s community and supported by Parkinson’s UK. It was a fantastic event and I was very grateful to the organisers for the invitation.

They kindly gave me two sessions (20 minutes each) which I divided into two talks: “Where we are now with Parkinson’s research?” and “Where we are going with Parkinson’s research?”. Since giving the talk, I have been asked by several attendees if I could make the slides available.

The slides from the first talk can be found by clicking here.

I have also made a video of the first talk with a commentary that I added afterwards. But be warned: my delivery of this second version of the talk is a bit dry. Apologies. It has none of my usual dynamic charm or energetic charisma. Who knew that talking into a dictaphone could leave one sounding so flat.

Anyways, here is the talk – enjoy!

I hope you find it interesting. When I have time I’ll post the second talk.

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The TAU of Parkinson’s

Here at the SoPD, we regularly talk about the ‘bad boy’ of Parkinson’s disease – a protein called Alpha Synuclein.

Twenty years ago this year, genetic variations were identified in the alpha synuclein gene that increase one’s risk of developing Parkinson’s. In addition, alpha synuclein protein was found to be present in the Lewy bodies that are found in the brains of people with Parkinson’s. Subsequently, alpha synuclein has been widely considered to be the villain in this neurodegenerative condition and it has received a lot of attention from the Parkinson’s research community.

But it is not the only protein that may be playing a role in Parkinson’s.

Today’s post is all about TAU.


Source: Wallpaperswide

I recently informed my wife that I was thinking of converting to Taoism.

She met this declaration with more of a smile than a look of shock. And I was expecting the latter, as shifting from apatheism to any form of religious belief is a bit of a leap you will appreciate.

When asked to explain myself, I suggested to her that I wanted to explore the mindfulness of what was being proposed by Lao Tzu (the supposed author of the Tao Te Ching – the founding document of Taoism).

This answer also drew a smile from her (no doubt she was thinking that Simon has done a bit of homework to make himself sound like he knows what he was talking about).

But I am genuinely curious about Taoism.

Most religions teach a philosophy and dogma which in effect defines a person. Taoism – which dates from the 4th century BCE – flips this concept on its head. It starts by teaching a single idea: The Tao (or “the way”) is indefinable. And then it follows up by suggesting that each person should discover the Tao on their own terms. Given that most people would prefer more concrete definitions in their own lives, I can appreciate that a lot of folks won’t go in for this approach.

Personally speaking, I quite like the idea that the Tao is the only principle and everything else is a just manifestation of it.

According to Taoism, salvation comes from just one source: Following the Tao.

Source: Wikipedia

Oh and don’t worry, I’m not going to force any more philosophical mumbo jumbo on you – Taoism is just an idea I am exploring as part of a terribly clichéd middle-life crisis I’m working my way through (my wife’s actual response to all of this was “why can’t you just be normal and go buy a motor bike or something?”).

My reason for sharing this, however, is that this introduction provides a convenient segway to what we are actually going to talk about in this post.

You see, some Parkinson’s researchers are thinking that salvation from neurodegenerative conditions like Parkinson’s will come from just one source: Following the TAU.

What is TAU?

Continue reading

Prothena reports Phase 1b results for Parkinson’s immunotherapy

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This week the biotech company Prothena released the results of their phase 1b clinical trial for their treatment, PRX002 (also known as RG7935).

This is one of the first immuno-therapies being tested in Parkinson’s disease, and the results indicate that the treatment was active and well tolerated.

In this post we will review the press release and what it tells us regarding this clinical trial.


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Antibodies binding to proteins. Source: AXS

When your body is infected by a foreign agent, it begins to produce some things called antibodies. In most cases, these are Y-shaped proteins that binds to the un-wanted invader and act as a beacon for the immune system. It is a very effective system, allowing us to go about our daily business without getting sick on a regular basis. Antibodies allow us to build up immunity, or resistance of an organism to infection or disease.

Scientist have harnessed the power of this natural process, and they have use it to develop methods of helping our bodies fight off disease.

The first approach is called Acquired Immunity (or adaptive immunity), and it is based on the idea that exposure of the immune system to a pathogen (disease/damage causing agent) creates an ‘immunological memory’ within our immune system, and this leads to an enhanced response to subsequent future encounters with that same pathogen.

Scientists have used the idea of acquired immunity to develop what we call vaccines – which are simply small, neutral fragments of specific pathogen that help the immune system to build up immunity (or resistance) before the body is attacked by the disease-causing pathogen itself.

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Vaccination. Source: WebMD

The second approach is called Passive Immunity.

Passive immunisation is simply the sharing of antibodies. And that might sound a bit disturbing, but it is actually a naturally occurring process. For example, a mother’s antibodies are transferred to her baby in the womb via the placenta.

And again, scientists have devised ways of producing passive immunisation artificially. And recently researchers have been using this approach to attack many medical conditions (particularly cancer), in an area of medicine called immunotherapy.

Think of it as simply boosting the immune system by supplementing the supply of antibodies. Scientists can produce high levels of antibodies that specifically target a particular pathogen and then transfer those antibodies to affected people via an intravenous injection.

How is this being used for Parkinson’s disease?

Well, we have previously discussed the idea of a vaccine for Parkinson’s disease (click here to read that post), and we have been closely following the progress of an Austrian company, AffiRis, who are leading the vaccination approach (Click here for that post).

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Source: AffiRis

The vaccine approach is targeting the Parkinson’s disease associated protein, Alpha synuclein. It is believed that a bad kind of alpha synuclein is causing the spread of the condition, by being passed from cell to cell. The goal of the vaccine is to capture and remove all of the alpha synuclein being passed between cells and thus (hopefully) halt the progress of – or at least slow down – the disease.

And this week, another company – Prothena – has reported the results of their phase 1 trial for a passive immunity approach to Parkinson’s disease. They have been injecting subjects in the trial with a treatment called PRX002.

(Remember that a phase 1 trial simply tests the safety of a treatment in humans, it is not required to test efficacy of the treatment. Efficacy comes with phases 2 & 3 trials)

What is PRX002?

PRX002 is a monoclonal antibody. The scientists at the biotech company Prothena have artificially produced large amounts of antibodies to alpha synuclein and these have been injected into people with Parkinson’s disease.

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Monoclonal antibodies. Source: Astrazeneca

Prothena provide a short video explaining this concept (click here to view the video).

So what were the results of the Prothena study?

The study was conducted in collaboration the pharmaceutical company Roche. It was a double-blind (so both the researchers and subjects did not know what they were receiving until the conclusion of the study), placebo-controlled study involving 80 people with Parkinson’s disease. The subjects were randomly assigned to one of six groups, which received either PRX002 or a placebo. There were six doses of PRX002 tested in the study (0.3, 1, 3, 10, 30 or 60 mg/kg).

The study was conducted over six-month, during which patients received three once-a-month injections of either PRX002 or placebo. The subjects were then followed for an observational period of three months.

According to the press release, no serious treatment-related adverse events were reported in PRX002 treated patients. Mild treatment-related adverse events (greater than anything experienced within the placebo group) were noted in 4 of the 12 subjects in the highest dosage group of PRX002, including constipation and diarrhoea.

Importantly, the investigators reported that thePRX002 antibodies were crossing the blood brain barrier and entering the brain. This resulted in a rapid reduction of alpha-synuclein levels (in some cases by up to 97 percent after a single dose!).

The follow-on Phase 2 clinical study is expected to begin in 2017.

What is the difference between the vaccine and the passive immunity approaches?

Basically, it comes down to levels of control. With a vaccination, once you have injected the vaccine and the immune system is activated, there isn’t much you can do to control the response of the body. And that immune memory is going to last a long time. The passive immunity response, on the other hand, requires regular injections of antibodies which can be stopped if adverse effects are noted.

Plus – and forgive me if I sound a little bit cynical here – drug companies prefer a regular treatment approach (which they can charge for each visit) compared to a one-shot cure. It’s simply a better business model.

What happens next?

In both cases – the vaccine and the passive immunity approaches – phase 2 trials are being set up by the respective companies and we will wait to see have affective these treatments are at slowing down Parkinson’s disease.

If they are affective, expect big headlines in the media and plans for adults everywhere to start being vaccinated. If they fail,…. well, we will have to re-address our understanding of the role of alpha synuclein in Parkinson’s disease.

Interesting times lie ahead.


The banner for todays post was sourced from Prothena

Game changer for Alzheimer’s?

TOP-L-Concussion Front Page

Exciting results published this week regarding a small phase 1b clinical trial of a new treatment for Alzheimer’s disease. In this post, we shall review the findings of the study and consider what they may mean for Parkinson’s disease.


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An Alzheimer’s brain scans on the left, compared to a normal brain (right). Source: MedicalExpress

Alzheimer’s disease is the most common neurodegenerative disease, accounting for 60% to 70% of all cases of dementia. It is a progressive neurodegenerative condition, like Parkinson’s disease, affecting approximately 30 million people around the world.

Inside the brain, in addition to cellular loss, Alzheimer’s is characterised by the increasing presence of two features:

  • Neurofibrillary tangles
  • Amyloid plaques

 

 

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A schematic demonstrating the difference between healthy and Alzheimer’s affected brains. Source: MmcNeuro

The tangles are aggregations of a protein called ‘Tau’ (we’ll comeback to Tau in a future post). These tangles reside within neurons initially, but as the disease progresses the tangles can be found in the space between cells – believed to be the last remains of a dying cell.

Amyloid plaques are clusters of proteins that outside the cells. A key component of the plaque is beta amyloid. Beta-amyloid is a piece of a larger protein that sits in the outer wall of nerve cells where it has certain functions. In certain circumstances, specific enzymes can cut it off and it floats away.

 

 

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The releasing of Beta-Amyloid. Source: Wikimedia

Beta-amyloid is a very “sticky” protein and it has been believed that free floating beta-amyloid proteins begin sticking together, gradually building up into the large amyloid plaques. And these large plaques were considered to be involved in the neurodegenerative process of Alzheimer’s disease. Thus, for a long time scientists have attempted to reduce the amount of free-floating beta-amyloid in the brain. One of the main ways they do this is with antibodies.

What are antibodies?

An antibody is the foundation of our immune system. It is a Y-shaped structure, that is used to alert the body when a foreign or unhealthy agent is present.

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An artist’s impression of a Y-shaped antibody. Source: Medimmune

Two arms off the Y-shaped antibody have what is called ‘Antigen binding sites‘. An antigen is a molecule that is capable of inducing a response from the immune system (usually a foreign agent, but it can be a sick/dying cell).

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A schematic representation of an antibody. Source: Wikipedia

There are currently billions of antibodies in your body -each with specific sets of antigen binding sites – awaiting the presence of their antigen. Antibodies are present in two forms: secreted, free floating antibodies, and membrane-bound antibodies. Secreted antibodies are produced by B-cells, which are part of the immune system. And it’s this secreted form of antibody that modern science has used to produce new medicines.

Really? How does that work?

Scientists can make antibodies in the lab that target specific proteins and then inject those antibodies into a patient’s body and trick the immune system into removing that particular protein. This can be very tricky, and one has to be absolutely sure of the design of the antibody because you do not want any ‘off-target’ effects – the immune system removing a protein that looks very similar to the one you are actually targeting.

These manufactured antibodies are used in many different areas of medicine, particularly cancer (over 40 antibody preparations have been approved by the U.S. Food and Drug Administration for use in humans against cancers). Recently, large pharmaceutical companies (like Biogen) have been attempting to use these manufactured antibodies against other conditions, like Alzheimer’s disease.

Which brings us to the study published this week:

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Title: The antibody aducanumab reduces Aβ plaques in Alzheimer’s disease.
Authors: Sevigny J, Chiao P, Bussière T, Weinreb PH, Williams L, Maier M, Dunstan R, Salloway S, Chen T, Ling Y, O’Gorman J, Qian F, Arastu M, Li M, Chollate S, Brennan MS, Quintero-Monzon O, Scannevin RH, Arnold HM, Engber T, Rhodes K, Ferrero J, Hang Y, Mikulskis A, Grimm J, Hock C, Nitsch RM, Sandrock A.
Journal: Nature. 2016 Aug 31;537(7618):50-6.
PMID: 27582220

In this study, the researcher conducted a 12-month, double-blind, placebo-controlled trial of the antibody Aducanumab. This antibody specifically binds to potentially harmful beta-amyloid aggregates (both small and large). At the very start of the trial, each participants was given a brain scan which allowed the researchers to determine the baseline level of beta-amyloid in the brains of the subjects. 

All together the study involved 165 people, randomly divided into five different groups: 4 groups received the 4 different concentrations of the drug (1, 3, 6 or 10 mg per kg) and 1 group which received a placebo treatment. Of these, 125 people completed the study which was 12 months long. Each month they received an injection of the respective treatment (remember these are manufactured antibodies, the body can’t make this particular antibody so it has to be repeated injected).

After 12 months of treatment, the subjects in the  3, 6 and 10 mg per kg groups exhibited a significant reduction in the levels of beta-amyloid protein in the brain (according to brain scan images), indicating that Aducanumab – the injected antibody – was doing it’s job. Individuals who received the highest doses of Aducanumab had the biggest reductions in beta-amyloid in the brain. Interestingly, this reduction in beta-amyloid in the brain was accompanied by a slowing of the clinical decline as measured by tests of dementia.  Individuals treated with the placebo saw neither any reduction in their brain levels of beta amyloid nor their clinical decline.

The authors considered this study strong justification for larger phase III trials. Two of them are now in progress, with completion dates expected around 2020.

So this is a good thing right?

Yes, this is a very exciting result for the Alzheimer’s community. But the results must be taken with a grain of salt. We have discussed beta-amyloid in a previous post (Click here for that post). While it has long been considered the bad boy of the Alzheimer’s world, the function of beta-amyloid remains the subject of debate. Some researchers worry about the medical removal of it from the brain, especially if it has positive functions like anti-microbial (or disease fighting) properties.

Given that the treatment is given monthly and can thus be controlled, we can sleep easy knowing that disaster won’t befall the patients receiving the antibody. And if they continue to demonstrate a slowing/halting of the disease, it would represent a MASSIVE step forward in the neurodegenerative field. I guess what I am saying is that it is too soon to say. It will be interesting, however, to see what happens as these patients are followed up over time. And the two phase 3 clinical trials currently ongoing, which involve hundreds of participants, will provide a more definitive idea of how well the treatment is working.

So what does this have to do with Parkinson’s disease?

Yeah, so let’s get back to our area of interest: Parkinson’s disease. Biogen is the pharmaceutical company that makes the Alzheimer’s antibody (Aducanumab) discussed above. Biogen is also currently conducting a phase 1 safety trial (on normal healthy adults) of an antibody that targets the Parkinson’s disease associated protein, alpha synuclein. We are currently waiting to hear the results of that trial.

Several other companies have antibody-based approaches for Parkinson’s disease (all of them targeting the protein alpha synuclein). These companies include:

There are some worries regarding this approach, however. For example, alpha synuclein is highly expressed in red blood cells, and some researchers worry about what affects the antibodies may have on their function. In addition, alpha synuclein has been suspected of having anti-viral properties – reducing viruses ability to infect a cell and replicate (click here to read more on this). Thus, removal of alpha synuclein by injecting antibodies may not necessarily be a good thing for the brain’s defense system.

Unlike beta-amyloid, however, most of alpha synuclein’s activities seem to be conducted within the walls of brain cells, where antibodies can’t touch it. Thus the hope is that the only alpha synuclein being affected by the antibody treatment is the variety that is free floating around the brain.

The results of the Alzheimer’s study are a tremendous boost to the antibody approach to treating neurodegenerative diseases and it will be very interesting to watch how this plays out for Parkinson’s disease in the near future.

Watch this space!


The banner for today’s post was sourced from TheNewsHerald

Vaccination for Parkinson’s disease

There has never been a more exciting time in Parkinson’s disease research. At no point in the past has the progress been made at such a frenetic pace. New week, new discoveries. And it has to be said that none of this would be possible without the advocacy and fundraising efforts of groups such as the Michael J Fox foundation, the Cure PD Trust, and Parkinson’s UK.

In addition to learning a great deal about the basic science of Parkinson’s disease – a better understanding of the biology underlying the disease – we are also making tremendous gains in new areas of treatment. Until now, the basic treatment has been dopamine replacement with L-dopa. But now, like never before, novel therapeutic approaches are being tested in the clinic.

One of these new approaches, however, is based on a very old idea: Vaccination.

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Edward Jenner (1749 – 1823). Source: Wikipedia

While Edward Jenner is considered to be the pioneer of the world’s first vaccine (for Smallpox), the idea of vaccination/inoculation actually originated in India in 1000 BC, where it was briefly mentioned in Sact’eya Grantham, an Ayurvedic text. The first really credible mention of inoculation, however, was in China where it was described in the book Yuyi cao (寓意草 or Notes on My Judgment) by Yu Chang, published in 1643.

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Vaccination. Source: WebMD

The basic idea of vaccination is to deliberately introduce an individual to a small component of a disease-causing agent so that the body can build up an immune response to the disease prior to being attacked by the full disease.  That fragment of the disease-causing agent becomes what is known as an an ‘antigen’ (this comes from a French word, antigène, derived from the Greek anti- or “against”, and the word-forming suffix -gen, “thing that produces or causes”), and it will serve as the target for the immune system. In response to the antigen, the body produces beacons that bind to the antigen for the immune system to look out for  – these beacons are called ‘antibodies’, and they tell the immune system that what they have bound to is ‘not of this body – get rid of it’!

Vaccines will sometimes be made of an empty virus – the surface of the virus will be present, but the internal disease-causing mechanisms have been destroyed or removed. Think of it as training the immune system for some big event. In this way, by exposing and thus priming the body against a particular part of s disease-causing agent, if the body is ever attacked by the full agent, the immune system will be ready to deal with it.

So what does this have to do with Parkinson’s disease?

Good question!

In July of 2014, a small Austrian company called “AFFiRiS” announced the results of one of their first clinical trials for Parkinson’s disease.

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The AFFiRiS drug (called PD01A in the AFF008 trial)  is an vaccine that targets the Parkinson’s disease-related protein ‘Alpha-synuclein’. The vaccine causes the body to produce Alpha-synuclein-specific antibodies. These antibodies allow the immune system to then attack and remove this protein from the blood and fluid surrounding the brain. Any loose alpha-synuclein floating around should be removed.

Alpha-synuclein is a very common protein in the brain – it makes up about 1% of the material in neurons. It is also one of the proteins that is present in the ‘Lewy bodies’ that are associated with Parkinson’s disease.

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A cartoon of a neuron, with the Lewy body indicated within the cell body. Source: Alzheimer’s news

Lewy bodies are one of the defining characteristic features of the Parkinsonian brain (having said that, it is interesting to note that approx. 30% of the population over the age of 70 will have Lewy bodies but no clinical symptoms/problems). They are densely packed, spherical shaped, clusters of protein inside the cell body. We are not entirely sure if they are causing cells to die, but they should not be there so it is assumed that if we get rid of them, the cells will be healthier.

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An actual photo of a Lewy body (brown) within a neuron. Source: Medicalia

Given that Alpha-synuclein is one of the major components of Lewy bodies, it is the first protein to be targeted by a vaccine for Parkinson’s disease. Some researchers believe that the passing of Alpha synuclein from one cell to another may be the mechanism by which the disease spreads. By removing any Alpha-synuclein that floating around outside of cells, companies like Affiris hope that they will be able to slow down or even halt the spread of Parkinson’s disease within the brain.

The results from the first Affiris trial look rather promising.

The phase one trial run by Affiris was very small (just 12 subjects received the vaccine) and lasted only 12 months. The primary endpoint of any phase one trial is ‘safety and tolerability’ – that is to say, the study is a test of whether the drug is ok for humans use and can be well tolerated (e.g. it has no hidden/unknown side effects). Two different doses of the PD01A vaccine were given in the study and both were well tolerated by the participants in the study.

The Affiris researchers, however, were also looking at a second endpoint in their trial: whether the vaccine caused Alpha Synuclein-specific antibodies to be produced. Thankfully, Affiris found measurable levels of alpha-synuclein-specific antibodies in serum samples (a component of blood) and cerebrospinal fluid (the liquid surrounding the brain) collected from their participants, suggesting that the vaccine is doing it’s job and causing the immune system to react to the antigen being introduced.

Obviously a larger study is now required to determine if the vaccine will actually slow or halt Parkinson’s disease, but when the Affiris researchers compared the subjects in their first trial that received the vaccine with a group of control subjects at the end of the 12 months, they claim that they found PD01A subjects ‘functionally stabilised compared to the control group’.

And Affiris is not the only biotech company trialling the vaccine approach for Parkinson’s disease. In March 2015, an Irish company called ‘Prothena‘ announced that their vaccine reduced Alpha synuclein levels in the serum by 96%! And again the vaccine was well tolerated, with few side effects. 40 subjects were used in the Prothena study and the company will continue to follow them. They expect to release follow-up data – with clinical and imaging results – in early to mid 2016.

We will be watching this area of research very closely. Fingers crossed!