Abbott Laboratories v. Novopharm[1]
This was a Paragraph IV certification case[2] filed after Novopharm filed an ANDA to market a generic form of fenofibrate prior to expiration of the relevant patent. The certification asserted that the generic product would not infringe the patent. The main claim of the patent was to a therapeutic composition “containing a co-micronized mixture of particles of fenofibrate and a solid surfactant wherein the mean particle size of said co-micronized mixture is less than 15 µm. Novopharm micronized fenofibrate before mixing with a surfactant, but carried out certain wet granulation steps after mixing with surfactant and other excipients, which further reduced the size of the fenofibrate particles.
The issue was what was meant by “co-micronized” and whether any equivalents of co-micronization were covered. The Northern District of Illinois held that held that in this case “co-micronized” meant that the relevant steps had been taken in the absence of additional excipients so that there was no literal infringement and that prosecution history estoppel precluded infringement under the doctrine of equivalents.
The Federal Circuit affirmed. On the question of claim construction, the court found that prior to the invention the term “co-micronization” was unknown. However, the specification defined it as meaning “micronization of an intimate mixture of fenofibrate and a solid surfactant. The court noted that this was a case of the applicant acting as its own lexicographer. The court concluded that the use of the word “intimate” in this definition meant that the mixture being micronized must consist essentially of the two materials specifically mentioned. Hence any size reduction that occurred during Novpharm’s granulation stage did not fall within this definition because other excipient materials were present and so there was no literal infringement.
On the question of the doctrine of equivalents, the Federal Circuit held that the district court had erred in holding that amendments made during prosecution had relinquished all formulations in which fenofibrate had been pre-micronized. However, the error was harmless because on the correct application of the prosecution history estoppel, the same result would have been achieved. During prosecution, the applicant had distinguished prior art which disclosed pre-micronization as the sole micronization step for fenofibrate. The district court’s approach would have precluded application of the doctrine of equivalents even if a subsequent co-micronization had been carried out. The Federal Circuit did not believe that what was relinquished went this far and that had a subsequent co-micronization taken place this would still have been covered by the claims (quaere: would this not then have been literal infringement so that one need not have bothered about prosecution history estoppel?) In the present case, there was no size reduction of fenofibrate after its micronization that involved mixing with a. solid surfactant and so there was no infringement. In the granulation step the other materials present were in solution and therefore did not meet the requirement for the presence of a solid surfactant. Consequently, whatever was done at this stage did not meet the requirement for co-micronization. To ignore this requirement would violate the all elements rule. Therefore the finding of non-infringement was upheld.
[1] 66 USPQ2d 1200 (Fed. Cir. 2003).
[2] Under 21 USC 355(j)(2)(A)(vii)(IV) part of the Hatch Waxman amendments to the Food Drug and Cosmetic Act which tie in with 35 USC 271(e), persons seeking to market generic versions of drugs by filing an Abbreviated New Drug Application (ANDA) have to make certain certifications about the patent position on the drugs which they wish to be authorized to market. The options are set out in paragraphs within this subsection. Paragraph IV sets out the option for the generic manufacturer to assert that any patent that has been listed as being relevant to the drug in question by its originator is either invalid or not infringed. (The Food and Drug Administration maintains a list, the so-called Orange Book, which notes the patents which drug originators have indicated to be relevant to particular products.) . The patent infringement action in the present case was brought under the provisions of 35 USC 271(e) that enable suit for patent infringement prior to the actual sale of a product when a paragraph IV certification has been made in the ANDA.