Biotech Values

[exwannabe]

Some early halt info.

From the FDA: http://www.fda.gov/cber/gdlns/clintrialdmc.pdf


"Such boundaries can serve as useful guidelines to the DMC in making recommendations regarding continued accrual to and conduct of the trial. The DMC will usually recommend termination when these thresholds are crossed, but it is not obligated to do so, since other aspects of the interim data may complicate the issue. For example, the data on effectiveness may be very strong, with a stopping boundary having been crossed, but emerging safety concerns may make the benefit-to-risk assessment non-definitive at that interim review. FDA expects the sponsor to direct the DMC to exercise its own judgment in such circumstances; the DMC can be flexible in assessing the data relative to the stopping boundaries. If the DMC recommends early termination for efficacy before a boundary is crossed, however, and this recommendation is implemented, the Type I error cannot be preserved and the study results may be difficult to interpret."

I.E., the DSMB can recommend to halt the trial early in such a case, but the FDA will seriously question the data. "difficult to interpret" is not good, particularly in a P3.

Let's try an easier argument. If the DSMB should stop at p=.02, then that is what the SPA should say.