The Other Shoe Drops: ViroPharma Sues FDA – Challenges Denial of 3-Year Exclusivity and ANDA Approvals

April 16, 2012

By Kurt R. Karst –      

Last Friday, ViroPharma Incorporated (“ViroPharma”) filed a Complaint and a Motion for Temporary Restraining Order And/Or Preliminary Injunction in the U.S. District Court for the District of Columbia challenging FDA’s approval of three ANDAs for generic versions of ViroPharma’s VANCOCIN (vancomycin HCl) Capsules (Case No. 1:12-cv-00584-ESH).  The lawsuit follows FDA’s April 9, 2012 response to a March 2006 petition for stay of action submitted by ViroPharma (and supplemented on several occasions since).  FDA largely denied ViroPharma’s requests and approved ANDAs for generic VANCOCIN (see our previous post here).  FDA determined that the Agency “has clear legal authority to recommend in vitro dissolution data to demonstrate generic vancomycin bioequivalence,” and that a December 2011 supplemental NDA FDA approved for VANCOCIN is not eligible for 3-year exclusivity because of the limitation on such exclusivity for a so-called “old antibiotic” like vancomycin set forth in FDC Act § 505(v) as added by Section 4 of the 2008 QI Act.

According to ViroPharma, FDA violated the Administrative Procedure act (“APA”) “by adopting and applying in vitro dissolution testing as the bioequivalence testing method for vancomycin, in direct conflict with the FDA’s own regulations, and by basing its approval of the three generic vancomycin ANDAs on this improper in vitro testing.”  In approving ANDAs for generic VANCOCIN, says ViroPharma, “FDA did not follow its own rules, the plain text of which require that bioequivalence be established through in vivo testing absent a waiver unavailable under the circumstances at issue here.  Accordingly, the agency’s ‘deviant action’ must be invalidated.”   FDA’s regulations at 21 C.F.R. Part 320 discuss the various requirements for bioequivalence testing, including the various types of tests available to meet in vivo or in vitro requirements. “Nowhere in § 320.22, or anywhere else in the regulations, does it state that FDA has discretion to approve ANDAs based solely on in vitro testing whenever it chooses and regardless of whether any of the circumstances in § 320.22 are satisfied,” says ViroPharma.

With respect to FDA’s denial of 3-year marketing exclusivity, ViroPharma alleges that FDA violated the APA and the FDC Act (§ 505(c)(3)(E)(iv) & § 505(j)(5)(F)(iv)).  According to ViroPharma:

FDA erred in concluding that every one of the recent fundamental and extensive changes to Vancocin’s labeling constitutes a “condition of use for which” Vancocin “was [previously] approved.”  To the contrary, virtually all of those changes, including in particular the new renal monitoring and dosing requirements, constitute new conditions of use not previously approved, and ViroPharma is therefore entitled to three-year exclusivity (running from December 14, 2011, to December 15, 2014) for its new label.  Critically, even if just one of Vancocin’s labeling changes qualifies for exclusivity, then the entire basis for the FDA’s rejection of exclusivity and hence for approving the generic vancomycin ANDAs is undermined. 

ViroPharma seeks an Order and Judgment holding unlawful and setting aside FDA’s in vitro bioequivalence method for vancomycin, FDA’s petition denial, and FDA’s ANDA approvals.  ViroPharma also seeks an Order and Judgment compelling FDA to grant a period of 3-year exclusivity for VANCOCIN, and enjoining FDA from granting further ANDA approvals.

The case has been assigned to Judge Ellen S. Huvelle, who is also handling a challenge to 180-day marketing exclusivity for a generic version of Cephalon’s PROVIGIL (modafinil) Tablets (see our previous post here).  Late last Friday, Judge Huvelle issued a Minute Order ordering the government to file its response to ViroPharma’s Motion for a Temporary Restraining Order by no later than Tuesday, April 17, 2012, at 5:00 PM, and also ordering that any party seeking to intervene to file its response by no later than Tuesday, April 17, 2012, at 5:00 PM.  A hearing on ViroPharma’s Motion for a Temporary Restraining Order is set for Thursday, April 19, 2012, at 2:30 PM.

ViroPharma’s challenge to FDA’s denial of 3-year marketing exclusivity is the second such challenge in recent weeks involving 3-year marketing exclusivity.  Currently pending before the D.C. District Court are Motions for Summary Judgment filed by FDA and AstraZeneca Pharmaceuticals LP (here and here) concerning FDA’s approval of ANDAs for generic versions of SEROQUEL (quetiapine fumarate) Tablets and the Agency’s decision, discussed in a March 27, 2012 Letter Decision, concerning the scope and applicability of 3-year marketing exclusivity in that case.