In the statutory double-patenting context, claim domination arises where one patent’s claim reads on an invention defined by a more specific claim in another patent. The former dominates the latter because the narrow claim cannot be practiced without infringing the broader claim. Although domination is not per se double-patenting, the doctrine does have its boundaries: a patentee who disclosed ABCXY and claimed ABCX cannot later claim ABCXY beyond the expiration of the patent. This attempt at an extension constitutes double-patenting.
According to district judge Sue L. Robinson, any attempt to meld both tests impermissibly broadens the double-patenting inquiry. In the underlying litigation, the party asserting invalidity contended that double-patenting occurs where the earlier patent discloses and covers the subject matter claimed in the later patent and the evidence reflects that the patentee could have presented the new claims in the earlier prosecution. Or to put it another way: the claims dominate and the patentee already had a chance to claim additional subject matter.
The Court rejected this hybrid test, “unrecognized by any court,” on two grounds. First, the test impermissibly adds a new element – opportunity – to the existing precedent, as “only the claims of the patent can be considered as support for a double-patenting rejection.” And second, domination alone is insufficient to establish that the two claim sets are “patentably distinct”:
[A stipulation that the new claims] cannot be practiced without infringing at least one claim of the [earlier patent] indicates that there is overlapping subject matter; this is not an admission that the sets of claims are not patentably distinct from one another.”