In a letter issued April 24, 2014 to ANDA applicants for Celecoxib, the FDA explained its rather complicated view of how to treat reissue patents as they relate to 180-day exclusivity and 30-month stays (here).  And, in this case, the FDA did not provide a decision on 180-day exclusivity for any Celecoxib applicant because exclusivity determinations are not made until an ANDA that may be subject to either 180-day exclusivity or may be blocked by such are approved.  In the former case, FDA would indicate the eligibility for the 180-day exclusivity, and, in the latter, would issue a Tentative Approval letter indicating that the application (while meeting all other approval requirements) cannot receive final approval due to another applicant being eligible for 180-day exclusivity.  As things stand today, there are three firms that have tentative approval letters (Mylan, Teva, and Watson).

The FDA letter also covers a very specific fact set and deals only with pre-MMA applications.  In this case, none of the first filer(s) have received final approval.  There was patent litigation that found the original patent invalid.  Prior to any approval of any ANDA the original patent reissued (a reissue patent corrects some error in the original patent or otherwise may narrow or broaden the patent claims). [MS1] The reissue patent also has the same expiration date as the original patent.  The question then is, does the paragraph IV certification (which is required to address the reissued and relisted patent) lend itself to another 30-month stay and/or another 180-day period of exclusivity for first filer(s) to the reissue patent?  Part two was simple for FDA and they indicated that, because the reissue kind of reinstates the original patent, that it is a continuation of the patent, and, thus, there should not be a second 30-month stay associated with the new PIV certification.

As far as the 180-day exclusivity goes, the FDA believes that even though the first patent was found invalid (which would, under pre-MMA standards, trigger the running of the 180-day exclusivity period) that the first applicant should not be penalized for attacking the patent and, thus, the first applicant should still be entitled to 180-day exclusivity for their original PIV certification, as long as a timely certification to the reissue patent was made.

FDA cited three examples in their decision letter that they have had to face, relative to reissue patents and describes how they dealt with them.  While none of the three situations had quite the same fact pattern (two somewhat similarly situated applicants triggered their 180-day exclusivity by first commercial marketing either directly or by distribution of an authorized generic) and since first commercial marketing always triggers the exclusivity period, those situations differed in and of themselves.  In the third example, the reissue patent came after the ANDA approval, but FDA applied the Bundle of Patent approach outlined in their letter referenced above; thus, even though the firm won on the reissue patent (was found not to infringe), the exclusivity was, in fact, triggered by the win on the original patent and there was only 2 months left on the exclusivity.  FDA noted the following in their letter:

Although there is not a great deal of precedent with respect to 180-day exclusivity and reissued patents, the Agency previously has taken the following actions involving reissued patents in a pre-MMA context.  In these cases, FDA has consistently applied its single “bundle” of patent rights approach regarding reissued patents and 180-day exclusivity and has concluded that the original and reissued patent together give rise to a single 180-day exclusivity period.

And went on to note:

As noted above, in each of these three decisions, FDA treated the original and reissued patent as a single “bundle” of patent rights. In the case of Mircette, Barr (the first to file a paragraph IV certification with respect to the ‘843 patent for Mircette) made no objection to FDA’s decision that a single 180-day exclusivity period was triggered by the court’s decision that the reissued patent was not infringed, even though, at the time of its ANDA approval, only about two months remained on its 180-day exclusivity period.

FDA has taken no final action to approve any Celecoxib ANDA; however, in a news article published on 4/29/14, it was noted that Actavis and Mylan sued FDA on its Decision Memo because under its terms it would award 180-day exclusivity to Teva as a first filer to the original patent.  It will be interesting to watch this case and see how the ultimate decision unfolds.  Not being a lawyer, I would only venture to guess that the court may find the suit is not ripe because the FDA Decision Memo may not constitute final Agency action (i.e., the actual approval of the Teva application).