Pfizer v. Apotex (Fed. Cir. 2007).
Norvasc® is Pfizer’s patented blockbuster drugs for treating hypertension and angina. The Court of Appeals for the Federal Circuit (CAFC) has invalidated Pfizer’s patent — finding it obvious. Generics are already on the market.
Background: Apotex, a generic manufacturer, filed a notice with the FDA — certifying its belief that Pfizer’s patent covering Norvasc was invalid and unenforceable. The trial court upheld Pfizer’s patent and issued an injunction stopping Apotex from making a generic version.
Courts and the PTO: In its appellate opinion, the CAFC began with a strong repudiation of any reliance on Examiner’s findings during prosecution of a patent: “Our case law consistently provides that a court is never bound by an examiner’s finding in an ex parte patent application proceeding.” Applying this boundary, the panel found that “it can never be the case that an examiner’s interim finding of prima facie obviousness renders the claims of an issued patent prima facie obvious.”
Unpredictably Obvious: Norvasc is amlodipine besylate. At the time of the invention, amlodipine was known as was the use of besylate anions. Pfizer argued that the results of combining these would have been unpredictable and therefore non-obvious. The CAFC disagreed, finding that unpredictability does not result in nonobviousness.
[A] rule of law equating unpredictability to patentability, applied in this case, would mean that any new salt … would be separately patentable, simply because the formation and properties of each salt must be verified through testing. This cannot be the proper standard since the expectation of success need only be reasonable, not absolute.
Here, the court found plenty of evidence to believe that a PHOSITA would have had a reasonable expectation of success.
Obvious to try: A combination can be “obvious to try” but still be nonobvious. This is may be true, for instance, in cases where there are many potential parameters or where the art merely suggests a “general approach that seemed to be a promising field of experimentation.” The court distinguished those situations from the present case — finding that a PHOSITA would have been able to narrow the group of potential salt-formers to fewer than 53 anions, which would be an acceptable number to form “a reasonable expectation of success.”
Routine Experimentation: Start telling your story!! It is axiomatically true that patentability is not negated by the manner in which the invention was made. The exception, found here, is that “routine testing” can be considered a reason to invalidate the patent.
[T]he prior art provided not only the means of creating acid addition salts but also predicted the results, which Pfizer merely had to verify through routine testing.
Secondary Factors: On appeal, the CAFC also held that it was an error to consider Pfizer’s switch from a different form of amlodipine to amlodipine besylate as a secondary factor of obviousness. Furthermore, comparison of unexpected results must compare the invention to the closest prior art — not to the closest commercial product.
Orange Book Issues: Mylan was first to challenge the patent and lost. Under the Orange Book rules, Mylan still qualifies for six-months as the exclusive generic seller. Apotex, which won this case, claims that it also has rights to begin selling a generic version as soon as the FDA gives its approval. Apotex, however, has not presented its legal claim.
Expiration: When $2.4 billion per year are at stake, every day counts. The patent was set to expire on Sunday, although Pfizer claimed six additional months of exclusivity based on its testing of childhood eficacy.
- The patent had previously been upheld by three separate district courts.