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Biotech / Medical : Biotech Valuation -- Ignore unavailable to you. Want to Upgrade?

To: Biomaven who wrote (26900)	5/26/2008 12:10:31 PM
From: tuck	Respond to of 52153

>>But at the end of the day I believe a lot more late-stage drugs have died or been delayed by QTc issues than by animal tox studies. << I would guess you're right. Perhaps because a drug developer might see cell proliferation in in vitro studies very early, and quietly kill the compound before anybody hears about it. Whereas QTc signals aren't going to show up until an animal study at the earliest. So perhaps a small -- hard to detect in small samples -- QTc signal is more likely to show up relatively late? So even though you can test for it more quickly, you can't start as soon. This sort of thing is why we have large P3s . . . Anyhow, glad you're enjoying yourself. I'm a little jealous -- I've been landscaping so much that I've hardly climbed, and will likely hike today for the first time this year -- unlike me! This being May, did you sell before you went away? Or merely trust us to hold up the biotechs for you? Cheers, Tuck

To: Biomaven who wrote (26900)	5/26/2008 6:27:42 PM
From: Biotech Jim	Respond to of 52153

Peter- I have a different take on why drugs may fail. I think in the carcinogenicity studies, one does not see a signal until either a 6 month, 12 month, or longer read. If one sees a signal, then there may be species reasons why that may occur, and that is why it is frequently done in 2 species, and may be followed up in the cancer prone p53 mouse. I think that carc findings is a reason why some late stage compounds die. Many toxicologists are "high dose toxicologists", and that is fine as long as there are margins. Those that are lower dose toxicologists may be surprised by the agency's views (ie, negative if there is a low therapeutic index). In the long QT situation, in the past prior to electrophysiology tests that are current, one may have surprises (like the astemizole, terfenadine situation). Now the human ether a go go gene, aka hERG, is well understood to be the major reason for non genetic long QT. One usually tests for it in patch clamp studies prior to Ph 1. Also, one can assess in the normal path of dog CV studies prior to Ph 1. hERG is an excellent general predictor. So, I would be surprised if many drugs fail due to this issue in these days of predictive tests. Ultimately, efficacy is a major reason why drugs may fail, even in Ph 3. Or, even if efficacy is there, it may represent a marketability issue. Idiosyncratic issues can also crop up, and that represents a nightmarish situation. BJ