Amlodipine Besylate Exclusivity Issues – the FDA Front

The Federal Circuit’s March 22, 2007 decision invalidating Pfizer’s patent on NORVASC (amlodipine besylate), and Mylan’s commercial launch of its generic version approved under ANDA #76-418 later that day triggering the company’s 180-day exclusivity period has set off a flurry of activity, both in the courts and at FDA.  This case raises several interesting issues about the availability of 180-day exclusivity once a patent expires and the applicability of pediatric exclusivity.  FDA is being asked to address these issues in three recent citizen petitions submitted to the Agency concerning amlodipine drug products.

Yesterday, the Orange Book Blog reported on the United States District Court for the District of Columbia’s order granting Mylan’s Emergency Application for a Temporary Restraining Order and/or Preliminary Injunction, in which Mylan argues that “[i]n the past, the FDA has taken the position that 180-day generic exclusivity does not survive patent expiration [and that there] is no basis in the Hatch-Waxman Act for such a limitation.”  Pursuant to the court’s order, FDA is enjoined from approving any other ANDAs for generic NORVASC until at least April 13, 2007 at 5:00PM, and after FDA “solicit[s] the views of other interested parties on this matter by April 4, 2007 [to] render an agency decision on April 11, 2007.”  The Federal Circuit also ordered Pfizer and Mylan “to respond, no later than 10 a.m. on Monday, March 26, 2007, concerning how the invalidity determination affects the pediatric exclusivity period and the ANDA approval.”

Simultaneous with FDA’s solicitation and consideration of views on this 180-day exclusivity issue, the Agency must now also consider several citizen petitions concerning amlodipine drug products. 

On March 26, 2007, Mylan submitted a petition to FDA (Docket No. 2007P-0116) requesting that FDA stay the approval of any additional ANDAs for generic amlodipine products until after Mylan’s 180-day exclusivity expires on September 23, 2007.  Mylan’s arguments hew closely to those the company made in its Emergency Application.

On March 21, 2007, Pfizer submitted two petitions (Docket Nos. 2007P-0110 and 2007P-0111) requesting that FDA enforce pediatric exclusivity rights for amlodipine, and that FDA stay approval of any and all supplements to LOTREL concerning amlodipine and pediatric exclusivity, respectively.  LOTREL is Novartis’s brand name version of the combination of amlodipine besylate and benazepril hydrochloride.  Although Pfizer’s petitions do not concern Mylan’s ANDA approval specifically, they do raise raise issues concerning the applicability of Pfizer’s pediatric exclusivity for amlodipine, and whether the LOTREL NDA is a 505(b)(2) application subject to that exclusivity. 

UPDATE:

• FDA Docket No. 2007N-0123 established to solicit comments on amlodipine exclusivity issues