I admit that I have been rather dilatory in rendering some graphics, here, in order to help amplify a very-cogent (if deeply chemical) point offered by Salmon, last week, in our comment-box, for all of us "NON-rocket scientists" to see, more clearly. I am a visual learner -- I am sure others are, as well.
So, finally did I stay up late last night, to complete the glossy, three dimensional rendering of Vertex's teleprevir, and then twisted the rendering in space, on the page, to highlight just how strikingly-similar (though slightly shorter, and thus less-cluttered, or simpler) the competing Schering-Plough candidate, boceprivir, is to the Vertex candidate. Vertex's is labeled VX-950 -- teleprevir. Look first at it -- click to enlarge:
Okay -- now recall the rendering I created last week, for the "Name that Compound" trivial pursuit contest -- it is the Schering candidate, called "boceprivir":
Do you see -- especially nearest the mid-points of the two compounds -- the striking "familial resemblance"? So do I.
Now, read what Salmon wrote:
. . . .I'm so glad you're talking about mechanisms.
. . . .I do want to discuss a little bit about boceprivir.
This weekend I was thinking that for several different companies to all come up with structurally similar drugs for Hep C around the same time means that they all have a common mechanism that they're basing it on and the it must involve the part of the structure that's similar across molecules.
Then it struck me. Zyprexa, Lilly's wonder drug and that favorite of prosecutors and personal injury lawyers everywhere was noted to not only cause weight gain and diabetes in the original summary basis of approval. But it also caused severe liver toxicity in several people who were Hep C positive and structurally it has a metabolite that's very similar to boceprevir and the other ...previrs. Not only that, but there's a lot of information in the scientific literature that points to the same thing. In fact after Zyprexa, drug companies and FDA only started using people with non Hepatitis induced liver disease (e.g. alcoholic cirrhosis only) in hepatic impairment studies with new drugs and also began screening Hep C patients out of clinical trials.
I would absolutely bet my house that someone in FDA knows something about this and has been helping drug companies cover this up for the last 12 years or so.
The information is right there on the FDA's website. All anyone needs to do is look at the original reviews for Zyprexa and look at the metabolism of the quaternary Nitrogen. (In case anyone's interested just google Drugs@FDA.). . . .
-- Salmon
Salmon went on to write that he worried that much of this FDA reference material just might vanish into the ether -- if it were widely-seen, and well-understood. Let us now conduct that experiment. Will the FDA remove any, or all, of that linked material? I, for one, am skeptical. But, as ever, we shall see.
~~~~~~~~~~~~~~~~~
A Houseekeeping Note: I have placed a black-backgounded-version of the graphics here for PharmaGossip, and Peter Rost. Hint, hint. . . .]
2 comments:
Condor,
Thank you for the followup. While the mid-points of these molecules are the same it's the part to the right of it that is structurally similar to the substructure of some Zyprexa. Thus it's possible that the part you point out may be a part of the molecules that's responsible for efficacy. It's very difficult to say this for certain just looking at the molecules, however there might me something that's found on discovery if anyone should bring a case.
Diabetes and now liver toxicity and right in publicly available documents. Makes you wonder what else can might be hiding in plain site.
Salmon
Salmon -- great stuff!
We should learn much more about your "...privirs" theory at this conference, in the beginning of November 2008.
Teleprevir, boceprivir and Abbott's (earlier in the development cycle) entry will all be present -- and discussed, at length.
Cheers!
Post a Comment