[188] Prior to the enactment of this provision, the only relief that could be secured against importation into the United States of an unpatented product produced abroad by a process covered by a U.S. patent was by a proceeding before the International Trade Commission under the former 19 USC § 1337a.

[189] The Court of Appeals for the Federal Circuit has issued few decisions interpreting the material change exception of the Process Patent Amendments Act of 1988 .

In Bio-Technology General Corp v. Genentech Inc., 38 USPQ2d 1321 (Fed. Cir. 1996), Biotechnology General Corporation (BTG) imported into the United States human growth hormone (hGH) made outside of the U.S. Genentech owned two patents, the first patent claiming "a recombinant DNA method for producing a 191 or 192 amino acid human growth hormone (hGH) product that is identical, or essentially identical and functionally equivalent to natural hGH", and the second patent claiming a method "for constructing a replicable cloning vehicle (e.g., a plasmid) capable in a microbial organism of expressing a particular polypeptide (e.g., hGH)". BTG sued Genentech in district court seeking a declaratory judgment that the two patents were invalid, unenforceable and not infringed by BTG. Genentech counterclaimed for infringement and moved for a preliminary injunction barring BTG's importation of hGH on the basis that importation of hGH would infringe its patents under the PPAA. The district court granted the preliminary injunction finding that there was a substantial likelihood Genentech would succeed on its infringement claim based in part on the fact that BTG's process for producing hGH was within the literal scope of the claims of one patent and the process for making a plasmid that was used to produce the hGH was within the literal scope of a claim of the second patent.

The district court found that BTG's product was hGH and BTG's step of isolating and purifying hGH, while novel and the subject of a patent itself, fell within the scope of Genentech's claim. The court considered that the material change exception of the PPAA did not apply because the product made by the patented process and the product imported into the United States was not changed at all.

In respect to the second patent directed to a method of constructing a replicable cloning vehicle (e.g., plasmid), BTG argued that it did not infringe because it only constructed the plasmid once in Israel before enactment of the PPAA. The Federal Circuit noted that the statute does not specify what products will be considered to have been made by the patented process, apparently because Congress wanted the courts to resolve this question of proximity to the products of the patented process on a case by case basis. The district court found that BTG's hGH is a product made by the patented process because BTG uses the claimed process of making a replicable cloning vehicle as an essential part of the overall process for producing hGH. The district court relied on a passage of the legislative history of the PPAA:

The Federal Circuit, in affirming the district court's decision, noted that although the plasmid product of the claimed process of Genentech's second patent and hGH are entirely different materials and hGH is not a mere modification of the plasmid, the "legislative history ... indicated Congress's intent that infringement of a process for making a plasmid is not to be avoided by using it to express its intended protein."

In the second decision, Eli Lilly and Co v. American Cyanamid Co., 82 F.3d 1568, 38 USPQ 2d 1705 (Fed. Cir. 1996), the Federal Circuit considered the question whether the importation of the cephalosporin antibiotic cefaclor made using a patented process for preparing an intermediate used in the process of making cefaclor infringed that patent. The Federal Circuit first noted that the patented process had been used outside of the United States to prepare the cefaclor. However, since there are commercially viable noninfringing processes to produce cefaclor the patent in suit was not a "bottleneck". The Federal Circuit then considered functional and biological differences between the intermediate and cefaclor. The Federal Circuit concluded, based on the differences between the compounds, that the cefaclor that was imported into the United States was materially changed from the intermediate and thus no infringement would be found.

In Biotec Biologische Naturverpakungen GmbH & Co KG v. Biocorp Inc., 58 USPQ2d 1737 (Fed. Cir. 2001), it was found that the absorbtion of water during shipment did not make a material change to a thermoplastically processable starch, despite the fact that the claim recited that the product should be substantially water free.

[190] Mycogen Plant Science Inc. v. Monsanto Co., 58 USPQ2d 1891 (Fed. Cir. 2001).

[191] 35 USC § 287(b).

[192] 35 USC § 295.

[193] 14 USPQ2d 1734 (Fed. Cir. 1990).