When I went back over the most recent Momenta presentation (DB Biofest 12/15/10) this remark by Craig Wheeler stuck out:
Thanks to jbog for posting the transcript #msg-58235653
Though it could just be a CEO talking up his company I think there is a descent chance the courts could rule in Momenta's favor especially as others have implied the FDA unfairly used Momenta as the standard.
I think you are missing my point. For me it is plausible that in their development process Teva used methodology that would infringe MNTA's patent. But because they did that ex-US, I'm not sure MNTA has any recourse. If for their production methodology they do not infringe, then there is at least an argument that the product is not made in a manner that infringes MNTA US patents, and so they can import it legally.
Process/use patents are always weaker than COM patents, and more often than not there are clever ways to circumvent them. I think the Teva language about development occurring outside the US hints at their angle of attack.
The other issue that may come into play here is the statutory exemption from patent infringement for activities leading to the development (but not sale) of a generic drug. This was meant to allow generic companies to start the process of copying a patented drug before its patent expired, but maybe it comes into play here too.