<div class="FTQUOTE"><begin quote><i>Originally posted by: <b>Nedda</b></i>
Can I ask a favor???? Would someone taking VX-770 ask their doctor a question for me???? *PRETTY PLEASE* Would you ask them if they think there's a chance the drug would work on other CLASS III mutations.
VX-770 is aimed at correcting G551D and that is the ONLY mutation that they allowed in the studies, but other class III mutations are very similar to G551D. Our doctor said there wouldn't be enough of the other class III's to even do a study. But, my son carries R560T (and I know a couple other kiddos with it). R560T is a rare and severe mutation in class III, like G551D is. I really want to know if it's plausable or even logical to think that we may still have a chance with VX-770. I would like to hear what the doctors think. Our doctor said he didn't know (we are a smaller clinic that doesn't participate in the big trials). I'm trying to stay hopeful. The other mutation my son carries is DF508, so we are waiting on the other drugs as well. And praying for the success of them all for all of our CFers.
*sigh* I'm really, really, really wanting a chance to try VX-770. Hmmm... I wonder if the doctors do think it could work... if the insurance could refuse to let us try it since it wouldn't be for the specific mutation the FDA will have "approved" it for. I can't imagine trying to pay out of pocket for a possible $200,000 drug. Makes me sick to even think about. Sorry for my mid-morning ramblings.
If anyone would ask their doctor about vx-770 and class III mutations - I would sooooo greatly appreciate it.
Thank you so much,
Nedda
*ps - I had heard such wonderful things about vx-770, but my jaw dropped when i read that Joanna's son became pancreatic sufficient?!?!?! So exciting!!!</end quote></div><br><br>I am not a doctor, but I have been doing a lot of research about this because I want to know if it will work for my Class IV mutation, so I've read about how the drugs work and how various mutation work. I am VERY confident that it will work very well for other class III mutations. <br><br>This is my understanding - The problem with Class III mutations is that the CFTR channel is not open as often as it is supposed to be. In other words, there is a gate that is usually locked, which is why these are called "gating mutations." VX-770 makes that channel open much more often - it unlocks the rusty gate, therefore fixing the whole problem with Class III mutations. <br><br>In vitro research as shown that VX-770 increases the amount of time the channel is open in all types of cells, including those without any CF at all. So, in theory, it may help everyone with CF who has some CFTR that makes it to the bottom of the channel (mostly Class III and IV mutations, I think). However, Class IV mutations have other problems that VX-770 does not correct (like reduced potential difference).<br><br>The thing that gives me the most hope for Class III mutations is this quote from an abstract of a presentation made by Vertex, where they tested VX-770 in-vitro (in a test-tube): <br><br>"Class III mutations<br>demonstrated the largest VX-770 response, with all 8 class III mutations tested (e.g.,<br>G178R, G551D, G551S, G1349D) showing a >10-fold increase in Cl? transport<br>compared to baseline."<br><br>It also says: <br><br>"VX-770 also potentiated, albeit to a lesser extent, class IV<br>(conductance) mutations (e.g., R117H, D1152H, I148T), class II mutations that<br>result in a small amount of CFTR trafficking to the cell surface (e.g., F508del,<br>S549R), and multiple unclassified CFTR mutant forms." <br><br>And like a pp mentioned, there is a plan to expand the testing of the drug to include other Class III mutations, and potentially some other mutations.<br>