Dans la cause Pfizer, Inc., et al. v. Ranbaxy Laboratories, Limited, et (Fed. Cir. ; August 8, 2006), un problème technique au niveau de la construction de la revendication 6 du brevet U.S. No. 5,273,995 a causé son invalidité sous l’article 35 U.S.C. § 112, ¶ 4, selon lequel (en anglais):
a claim in dependent form shall contain a reference to a claim previously set forth and then specify a further limitation of the subject matter claimed.
Selon le Juge en chef Michel (citation originale en anglais),
We recognize that the patentee was attempting to claim what might otherwise
have been patentable subject matter. Indeed, claim 6 could have been properly
drafted either as dependent from claim 1 or as an independent claim—i.e., “the
hemicalcium salt of atorvastatin acid.” But, we “should not rewrite claims to
preserve validity.” Nazomi Commc’ns, Inc. v. Arm Holdings, PLC, 403 F.3d 1364,
1368 (Fed. Cir. 2005); see also Rhine v. Casio, Inc., 183 F.3d 1342, 1345 (Fed.
Cir. 1999) (“[I]f the only claim construction that is consistent with the
claim’s language and the written description renders the claim invalid, then . .
. the claim is simply invalid.”). Ranbaxy correctly argues that claim 6 fails to
“specify a further limitation of the subject matter” of the claim to which it
refers because it is completely outside the scope of claim 2. We must therefore
reverse the district court with respect to this issue and hold claim 6 invalid
for failure to comply with § 112, ¶ 4.