On Thu 29 Jul, judith richards wrote:
> 29 July 1999
> Drug firms go all out to dazzle doctors
>
I have been trying to make sense of the apparently revolutionary result produced
by SmithKline Beacham by testing a combination of Levodopa and Requip. After all,
obtaining an increase in operating margin (between on the one hand Parkinson
tremor, and on the other hand levodopa-related dyskinesias) without compromise
is quite simply the Holy Grail which we are all chasing.
********************
To get to the bottom line in one leap- Those folk who are in the starting blocks
and quivering, just waiting for the Drug Store (Chemists) to open. can stand down:
The optimum margin available is the same as it was yesterday. SKB have just
wrapped the package in a different way.
*******************
The attached chart, which I have deliberately kept very basic, is essentially an
extract from my note "A Model to Describe the Effect of Levodopa on a Person with
Parkinson's Disease". This paper can be read at Simon Coles web Site :
http://james.parkinsons.org.uk/
I will attempt a rough diagram in this email, which may convey the key message.
|NN Normal Behaviour
| NN
| NN
| NN
| NN
|30 NN
| NN
| NN
| NN A B C
| NN
|20 NN-D+L_D+L_D+L_D+LD+L+C+DA+L+C+.................
| NN LLL
| NN LL LL DA
| NN LL LL DA
| NN LL LDA
|10 LLNN DA LL
| LL NN DA LL
| LL NN DA LL
| LL NN
|__________________ _LL_____________NN______________________________________
30 40 50 60 70
( AGE )
NN NN NN Normal Behaviour
LL LL LL Levodopa
_D+L_D+L_D+L Combination of Dopamine + Levodopa
The diagram shows how I have worked my way through the levodopa tablets,
until I found the point where the Off-period shakes and the On-period
dyskinesias were almost super-imposed. (Point B) At this point,I then
introduced the dopamine agonist (Pergolide/Requip) and this takes me on to
point C where I am Balancing levodopa and Permax to obtain a stable point.
As this becomes a difficulty I open up the Pergolide by 500 micro grammes
and so far, I have stayed ahead of the game. The advantage that I gain by
putting the pergolide in as slowly as possible is the minimum exposure to the
side-effects.
If we consider what SKB did was doing, they picked a point about where I
was at age 50 , still on levodopa, but getting ready for change. Then they
started feeding their subjects the Requip in large quantities. This is an
acceptable way to go: the agonists, (All of the newer types from Permax on)
will perform as expected, although there is an increased risk of provoking
side-effects.
The simplest way to describe what they have done is that they have
mortgaged the future, by using all the Requip up at a relatively early age,
they then have to cope with advancing PD effects with only levodopa to manoeuvre.
This note is rather hurried, because I wanted to catch the debate which I can
feel, rumbling beneath my feet even as I write.
Comments please!!
--
Brian Collins <[log in to unmask]>
--
Brian Collins <[log in to unmask]>
