This is one of the world's most ambitious medical trials.
Searching for a cure for Parkinson's.
We're asking people to have an experimental device inserted into their heads
and we're asking people to have an experimental drug.
We could genuinely make people worse than they are before they started.
Only half the volunteers get the real drug and half just a placebo.
No one knows which.
There are some remarkable transformations.
It was like a bloody miracle.
But also major setbacks.
If this is as good as it gets
I'd be pissed off.
Is this the miracle cure that millions are hoping for?
The answer is...
Tom Isaacs was diagnosed with Parkinson's
17 years ago, when he was 27.
When I first was diagnosed you wouldn't even know I had it.
And it was like that for about the first five, six years.
Nowadays, everyone knows there's something going on.
Inflicting Parkinson's on someone you love is tough.
There are times when Lyndsey I'm sure thinks,
'God! What on Earth am I doing with this loser. He's just a shaking lump of jelly.'
In the UK there are almost 150,000 people with Parkinson's.
It's caused by a lack of the chemical dopamine in the brain
which affects your ability to move.
The drugs Tom currently takes can have major side effects.
My days, there's no rhyme or reason to them.
I can spend the day in perfect harmony with my body.
Pretty rare these days.
Or I can spend the day, seven hours shaking on the floor.
42 volunteers have been accepted onto the trial.
At 72, Ron Johnson is the oldest.
The main reason is totally and absolutely selfish.
I just want to play football... with my grandkids.
It's December 2012, and Tom arrives in Bristol for the surgery.
The drug he hopes to receive, called GDNF
should boost the levels of dopamine in his brain - if it works.
I know the drug works. It's a matter of how you get it in the right dose
in the right place, at the right time.
To get GDNF to where it's needed, the surgeons will implant 4 catheters deep into Tom's brain.
You can see every single blood vessel that you want to avoid
and it's quite a tangle, as you can see, that we need to miss to hit this target
but by having all this information we can determine exactly where to go.
This is our target.
See you on the other side.
Tom is one of the first volunteers to have the surgery.
The ground-breaking operation has never been performed on humans before.
After seven hours the catheters are implanted into the brain.
Then a port is embedded into the skull through which the drug can be applied.
Three months after the operation, Tom is ready to receive GDNF...
Fingers crossed for me people.
... or a placebo.
It's a huge day.
This is the first of 10 monthly infusions.
Simply the effect of going to see the doctor may begin to make you feel better.
Although it may seem cruel to put people through brain surgery
and then have half of them have to have dummy
there isn't really another way of deciding if one is genuinely better
than simply giving distilled water.
After a few infusions some volunteers are starting to show dramatic improvements.
But for Ron things have got worse.
If this is as good as it gets
I'd be pissed off.
Tom started off feeling better
but a few months later he believes he's been given a placebo.
You know what, I hope he's not on the drug.
So do I. It's made me worse.
Yeh, its made him worse.
Compared to this time last year before the surgery
I'd say I'm 20 to 30 percent worse than I was.
Really, really, it's been the year from hell.
Darren Calder also believes he's been on a placebo.
It's like I'm trapped in my own body
and I'm desperate to get out.
It didn't seem ethical to put people through having brain surgery
having the device inserted without ever having the prospect of the drug.
So halfway through the trials everyone starts to get GDNF.
And after a few months Darren begins to notice a difference.
I said you've got film this. This is unbelievable.
And now he's back!
I never expected none of this and I'd never seen it coming.
That's pretty well amazing!
To be honest with you, it scared me a little bit.
I was almost better off my meds the longer I went on.
Vicki Dillon has been improving since the start of the trial.
I can't explain it and we can't get our heads round it.
But it was like a bloody miracle.
Stand up out of the chair without using your arms.
But there's still no miracle for Tom.
The doctors think there's a problem with the catheters in his brain.
So they decide to put in new ones.
By the end of the trial Tom is hopeful the tests will show an improvement.
I've got this...
... just a little part of me is hoping that something wonderful is going to happen.
It turns out there's been a 50 percent improvement in four months.
After four years, and at a cost of £3 million
the results of the trial are being announced.
- A big day? - Very big day.
The future for GDNF and for millions of Parkinson's patients
hangs on what happens today.
For the trial to go to the next stage the data must show significant improvements.
So to remind you, we needed to see a 20 percent difference at the end of the study
between the treated group with GDNF versus the placebo group.
And the answer is...
... that sadly we did not meet the primary end point.
Everybody in the room was in a state of shock.
It was the end of hope I think. That's how it felt.
But despite failing to reach the required scores
there have been some remarkable findings.
Only four volunteers didn't show any improvement.
Everyone on GDNF saw a large increase in their dopamine levels.
And many showed a huge improvement in their movement.
Ron by 11 percent.
Darren by 50 percent.
And Vicki improved by more than 60 percent.
Even Tom eventually saw a slight improvement.
But in May the following year, Tom Isaacs was suddenly taken ill at home.
He was taken to hospital, but pronounced dead.
His mother said, when she came to see him
that she'd forgotten that he could be still.
A post-mortem reveals that Tom died of a heart condition
unrelated his Parkinson's or the trial.
It was a total shock and awful.
Because Tom was so central to everything we've done.
The GDNF trial has divided the scientific community.
Could the improvements have been down to a placebo effect?
The doctors are hoping that money can still be raised to carry on GDNF trials
and find a cure for Parkinson's.
It wouldn't be the first drug that's failed in clinical trials
and then come good, by any means.
Being a part of the GDNF trial was so inspiring
and gave Tom huge hope, huge hope for the future.