Replies to post #97882 on Biotech Values

[mcbio]

Re: RIGL/FDA (clinical vs. pre-clinical issues)

In my experience, the FDA tends to look at the clinical data, not theoretical concerns raised by preclinical studies. Of course if there is a cancer signal in the actual data, that would change the FDA's attitude radically.

Obviously if there are any pre-clinical signals with respect to a given drug, the FDA will step in and place a hold on any drug. I think you're just speaking generally about other companies doing pre-clinical tests on a given target. I.e., presumably RIGL has conducted extensive pre-clinical testing in mice and other species on R788 (its Syk inhibitor) to have confidence that there are no cancer concerns in animals (at least short to medium term) and that's why the drug is about to enter Phase 3 or otherwise the FDA would have already placed the drug on hold. Whether or not the lack of increased cancer risk pans out in humans remains to be seen of course. Also, presumably AZN did its own extensive DD to enter into partnership with RIGL for R788.

I think the study you cited before referenced testing in mice by Georgetown University and noting the signal with respect to inhibition of Syk potentially leading to increased breast cancer risk. Again though, I assume RIGL has conducted extensive testing in mice as well and already reported this to the FDA.

All told, perhaps I took a bit of an extreme bear view on RIGL given the prior news. If I could gain better confidence on the amount of pre-clinical testing RIGL has performed with respect to R788 to flesh out the lack of increased cancer risk related to Syk inhibition, perhaps I'll re-visit the company and stock again.