This piece of breaking news comes courtesy of Chris Campbell at DLA Piper.  We regret that, because of our own HT involvement here in Philly, we probably can’t do it justice.
There are two kinds of HT cases (actually, a lot more than two kinds, depending on the criteria, but humor us) – those involving HT with some form of progesterone, and those that don’t.  The former are more common than the latter, but there’s still a significant number of estrogen-only cases.
At least there were before In re Prempro Products Liability Litigation, MDL No. 4:03-CV-1507-WRW, slip op. (E.D. Ark. & D. Minn. Aug. 30, 2010).  Maybe not much longer.
The defendants (usually Wyeth, since its estrogen-only product, Premarin, was the most often used) won a Daubert motion precluding plaintiffs’ estrogen-only experts.  It was an unusual procedure, with two judges, the MDL judge in Arkansas and a Minnesota federal judge in some individual cases, ruling jointly.
Both of them agreed that the plaintiffs’ experts (Drs. Demirovic and Aldaz) couldn’t testify.
Why?
Let us count the ways.
(1) Their attempts to criticize the WHI study (which plaintiffs in the other type of HT case usually swear by, but which found no increased breast cancer risk in e-only HT) were lame – cherry picked from uncontrolled studies, statistically insignificant results, and salami-thin slices of data.  Slip op. at 6-9
(2)  Chemical composition analogies were not reliable.  Slip op. at 9-10.
(3)  The animal study results could not be reliably extrapolated to humans.  Slip op. at 11-12.
(4)  The opinion failed to establish a dose-response relationship.  Slip op. at 12-13.
It’s a good read, but that’s about all we can say.