Summary
The March 22, 2007 CAFC Opinion invalidates claims 1-3 of US Patent 4879303, which is listed in the FDA Orange Book for Pfizer's blockbuster blood pressure drug NORVASC® (amylodipine besylate). For companies other than Pfizer, this is great news - but it is not the end of the story. Numerous recent filings at the FDA and other courts plainly show that the NORVASC® disputes continue and that multiple parties with differing views are willing to fight to the end.
Analysis
In the linked Pfizer v Apotex case at the Court of Appeals for the Federal Circuit (CAFC), Pfizer (NYSE:PFE) sued Apotex for infringement of 3 claims (1-3) of the '303 patent. Note that this patent contains 11 claims (1-11). Many unresolved questions remain relating to the determination of the effect of such invalidation, see below.
Pfizer's position, as evidenced by recent filings, is that the March 22 decision did not by itself invalidate claims 1-3; it did not invalidate the entire patent; and it did not have any immediate effect on any unapproved ANDAs for amylodipine besylate. Although the '303 patent expired this March 25 (the natural expiration date), Pfizer argues 6-month pediatric exclusivity attached by operation of law to this expiration date; thus, any unapproved ANDAs cannot now be approved before September 25, 2007; and the '303 patent should remain Orange Book listed.
Watson Pharmaceuticals (NYSE:WPI) position is that the case has the following effects (all of of 03.25.07): the '303 patent is invalid; 6-months pediatric exclusivity vanishes; 180-days ANDA exclusivity vanishes; and Paragraph (iv) ANDA filings become immediately approvable.
Other generic companies are asserting a wide spectrum of other conflicting views; many litigations are now ongoing.
