Dec. 17, 2007
| "We haven't done Phase 0 or microdosing studies," says Dave Bearss, chief scientist at SuperGen
, a Dublin, Calif.-based cancer biopharma. "But we've spent a lot of time trying to figure out how they might help us." Says Bearss: "By the time we did a toxicology package needed for a Phase 0 study, we'd almost have what we needed to do a Phase I study. What's the cost-benefit of the Phase 0?"
For SuperGen, the key to microdosing studies would be getting into humans faster. "I mistrust animal models," says Bearss, although he's spent much of his career trying to make better ones. "Mice and rats don't make reliable human models, and even a monkey doesn't make a good human model."
Still, animal models do lots of work. "Exploratory INDs don't change how we would view using animal studies," says Brian Zambrowicz, executive VP and chief scientific officer for Lexicon Pharmaceuticals, "but it could help with ADME or pharmacokinetics to make a potentially difficult choice between promising drug candidates." He adds, "You need animal pharmacology to see if it is useful to take a compound into humans."
SuperGen might turn to Phase 0 studies if it needs to choose priorities from a group of similar compounds. In fact, SuperGen might face that situation soon. "We have three leads - two of them from the same chemical scaffold, and they are all pretty equivalent in the lab," says Bearss.
Zambrowicz and his colleagues see that benefit, too. "We considered using an exploratory IND in a case where we had two compounds, and all of our toxicology and animal pharmacology studies made these compounds look equivalent." But Lexicon hasn't turned to exploratory INDs yet.
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