VX770/VX809


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There has been a huge buzz in the CF community for some time now but last week some results were announced that could potentially change the future for our little ones and the many many people living with Cystic Fibrosis.

Vertex have been trialling a new drug that could actually fix the route cause of CF. I say 'fix' loosely as it isn't the full cure but it's pretty damn good.

The drug is VX770.

Now there are many drugs in the pipeline all the time but not many get as far as this one has. So this is huge and has definitely been one to watch with anticipation.

Here's the science bit..

To understand how this drug will work, you have to first understand the underlying problem in people with CF. I will do my best to explain (with a little help from external sources)...

Salt is made up of sodium and chloride and our bodies are very clever at regulating the level that wont cause problems and death. In people with Cystic Fibrosis, their bodies cannot transport chloride properly. This causes a build up in the body and the only reaction their bodies can do to balance out this overload is to increase production of sodium and therefore, water doesn't get distributed as it should.

This is the reason that when a person with CF sweats, they taste very salty and kick out much more salt than someone without CF.

However this is not just happening on the outside, it's affecting the inside too.
The cells that line the lungs and airways, digestive tract, sinuses and other organs can all be affected, because the body cannot regulate the concentration of salt properly resulting in the thick, sticky mucus that causes so many problems in people with CF.

So what does all this have to do with genes huh?

Well the gene that regulates sodium and chloride transport is known as the CFTR gene (cystic fibrosis trans membrane conductance regulator). The CFTR gene provides the information needed to transport sodium and chloride ions across the cell membrane. This in turn controls and regulates the flow of water in mucus, sweat, tears, saliva, and digestive enzymes.

The CFTR gene doesn't function properly in people with CF because they have inherited TWO (sometimes more) mutations of that gene.

It gets (more) complicated though as there are over 1500 known CFTR mutations and they are grouped into six categories. Each category upsets the CFTR gene differently but all cause Cystic Fibrosis, just in varying degrees.

So will VX770 fix all of this?

The answer in simple terms is no.

VX770 has been developed to target ONE specific mutation known as G551D which is a class 3 mutation (remember the categories I mentioned earlier).

In this particular mutation of the gene, the chloride is able to travel a good distance a long the tunnel of the cell but it hits a dead end as the gate is firmly closed. VX770 has been developed to open that gate and therefore allowing the CFTR gene to function as it should.

The results are out and they read very very well, so well in fact that I got rather excited when I read them. Sweat chloride levels had dropped to NORMAL ranges, little to no chest exacerbation's whilst taking the drug, weight gain and also great improvements in lung function.

This is huge.

So where's the catch?

I hate the fact that there is a catch but it's there with huge flashing neon lights I'm afraid. It has to be approved firstly and then licenced, and most importantly it will only be of any real use to 4% of people affected with CF. It also cannot reverse any damage already caused.

Sophie isn't part of the 4%.

Her mutations are DF508, which is a class 2 mutation and D1152h, which is a class 4 mutation.

This huge breakthrough will pave the way for future drug developments that hopefully one day, will target all mutations.

The exciting news for us is that Vertex already have another drug in the pipeline called VX809, which has been designed to target specifically the DF508 mutation, which would help Sophie.

The trials haven't been as promising as the 770 ones though, but they have been trialling VX809 in combination with VX770.

The problem with the DF508 mutation is the chloride isn't able to travel along the tunnel of the cell and if even it could, the gate at the end is firmly shut tight just like the G551D mutation. So the hope is VX809 would allow the chloride to flow down the tunnel and then VX770 would unlock the gate at the end, allowing for the CFTR gene to function properly.

This trial is still in it's early days, but compared to the placebo group, there have been improvements in function and sweat chloride has been reduced. We now have the long wait as a phase 2 trial is currently underway and results are to be announced later this year.

We all campaign for a cure, but honestly, unless the gene trials here in the UK and around the world work I'm not convinced that we will see one in Sophie's lifetime, however I remain optimistic and incredibly hopeful that drugs such as the VX770 and VX809 will be the next best thing.

So the main thing to bare in mind is the importance of keeping our kiddos as healthy as possible and any lung damage to a minimum. If the combined VX drugs work as well as 770 has on it's own, Sophie and her many friends will have a very promising future.

Exercise, treatments and good nutrition it is then!

I just want to extend our thanks to every single person who has/is participating in the drug trials as without you, we wouldn't have anything to be hopeful about.

If anyone has any questions please ask. I hope my take on things isn't too confusing as I only have what I consider a basic understanding of these things!

1 comment:

  1. I am a grandad of a 5 yr old with CF. I try to read up but confess to not fully understanding all that I read. My grandaughter has DF 508 and G551D. With this VX770 drug from what I read it could be beneficial to my grandaughter. You explain so well in your article that I hope you can do the same for me. As far as I can gather if someone only has 1 faulty gene they do not have CF and have no problems of cf type at all. Therefore if the new drug does what I read and does so much for the G551D gene what is the position regarding the other gene? If VX770 is successful will it also reduce the amount of daily 'physio, use of nebuliser etc. for the patient? I do hope that very soon the drug to help those like your little Sophie with DF508 will be available. I hope my questions have been clear enough and I wish your little girl and the thousands more out there with CF all the very best and I continually remember them and their parents in my prayers.

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