Wyeth Sues FDA & PTO Over Regulatory Review Period Determination for CYDECTIN PTE

On June 6, 2008, Wyeth Holdings Corporation and its Fort Dodge Animal Health Division (collectively “Wyeth”) filed a complaint in the U.S. District Court for the District of Columbia against FDA and the U.S. Patent and Trademark Office (“PTO”) requesting declaratory and injunctive relief with respect to Wyeth’s request for a Patent Term Extension (“PTE”) for U.S. Patent #4,916,154 (“the ‘154 patent”), which covers the company’s new animal drug CYDECTIN (moxidectin) Pour-On.  FDA first approved CYDECTIN on January 28, 1998 under New Animal Drug Application (“NADA”) #141-099 for the treatment and control of certain internal and external parasites of cattle.  Although Wyeth’s complaint is in the context of a PTE for an animal drug, a court decision could further clarify the PTE regulatory review period timeframes applicable to FDA-regulated products eligible for an extension.  In addition, this appears to be the first instance in which a company has challenged a PTE for a so-called Administrative NADA, a type of application discussed further below. 

Under 35 U.S.C. § 156(g)(4), as amended by the Generic Animal Drug Patent Term Restoration Act of 1988, certain patents covering animal drugs are eligible for a PTE if patent life was lost during a period when the product was undergoing regulatory review. As with other FDA-regulated products, such as human drugs and medical devices, the “regulatory review period” is composed of a “testing phase” and a “review phase.”  For animal drugs approved under FDC Act § 512, the “testing phase” begins on the earlier of the effective date of an Investigational New Animal Drug (“INAD”) exemption or the date a major health or environmental effects test on the drug was initiated, and ends on the date a NADA is “initially submitted” to FDA under FDC Act § 512(b).  The “review phase” is the period between the initial submission and approval of the NADA.  FDA’s PTE regulations at 21 C.F.R. § 60.22(f) clarify that a marketing application “is initially submitted on the date it contains sufficient information to allow FDA to commence review of the application.” A patent term may be extended for a period of time that is the sum of one-half of the time in the “testing phase,” plus all the time in the “review phase” (minus any of the “regulatory review period” that occurs prior to the patent issuance or during which the applicant did not act with due diligence to obtain approval).   The total (calculated) regulatory review period may not exceed 5 years, and the extended patent term may not exceed 14 years after the date of approval of the NADA.  The current case concerns when NADA #141-099 was “initially submitted” to FDA. 

Wyeth submitted a marketing application to FDA for CYDECTIN under the Agency’s Phased Data Review Policy and Administrative NADA process.  An Administrative NADA “is a new animal drug application that is submitted after all of the technical sections that fulfill the requirements for the approval of the new animal drug . . . have been reviewed by [the Center for Veterinary Medicine (‘CVM’)] and CVM has issued a technical section complete letter for each of those technical sections.”  In this respect, an Administrative NADA is similar to the statutory “Fast Track” process for human drugs and biologicals and the Modular Premarket Approval Application process for medical devices.  Both of these processes permit a type of rolling submission and review of marketing application sections.  As we previously reported, FDA and the PTO have addressed both processes with respect to PTE issues.  For example, under current FDA “Fast Track” policy and precedent, the Agency has determined that the date a final reviewable unit is submitted to the Agency is the date the PTE review phase begins.  Wyeth reportedly submitted the first technical section to the company’s INAD on August 8, 1995.  On January 13, 1998, after the submission and acceptance of the last technical section, and pursuant to Wyeth’s submission of an Administrative NADA for CYDECTIN, FDA issued an acknowledgement letter for the application.  Sixteen days later, on January 28, 1998, FDA approved NADA #141-099. 

In March 1998, Wyeth timely submitted an application to the PTO requesting a PTE with respect to the ‘154 patent.  In that application, Wyeth calculated a PTE based on the date the company submitted the first technical section to its INAD (i.e., August 8, 1995).  Using this date, Wyeth calculated a new expiration date of the ‘154 patent of January 28, 2012. (The original expiration date of the ‘154 patent was April 10, 2007.) 

In September 2006, FDA issued a Federal Register notice stating the Agency’s determination that the date NADA #141-099 was initially submitted to FDA was on January 13, 1998.  In the notice, the Agency also stated that “[i]t is FDA’s position that the approval phase begins when the marketing application is complete.”  In November 2006, Wyeth submitted a request for reconsideration and revision of the regulatory review period, in which the company argued that August 8, 1995 is the controlling date for PTE purposes.  On May 7, 2008, FDA denied Wyeth’s request.  FDA’s letter provides two bases for the Agency’s decision:

First, for phased review applications, it is FDA’s position that the approval phase for purposes of [PTE] begins when the marketing application is complete, including all technical sections and the CVM complete letters.  This correlates to the “fast track” and “rolling review” of human drug applications in that applications submitted under those programs are not considered initially submitted until all required technical information is addressed and available for FDA decision making to commence. . . . 

Second, the technical sections of the administrative NADA are submitted for FDA review not to the NADA, but to the INAD.  Regulatory review of the components is conducted under the first investigational phase of the regulatory review period allowing for review of the data at the time most appropriate and productive in the drug development process. . . .

A few weeks after FDA’s decision, Wyeth filed its complaint.  The complaint alleges that using the August 8, 1995 for purposes of calculating the regulatory review period is consistent with Congress’ intent in passing the PTE provisions at 35 U.S.C. § 156 and with FDA’s PTE regulations at 21 C.F.R. 60.22(f), and that a mere 16-day approval period “is unreasonable.”

Wyeth’s complaint asks for a declaratory judgment that FDA’s determination of the regulatory review period for CYDECTIN violated the FDC Act and the Agency’s implementing regulations, as well as injunctive relief directing FDA to recalculate the CYDECTIN regulatory review period and directing the PTO to refrain from issuing a certificate of extension for the ‘154 patent until FDA has recalculated the PTE period consistent with the law.

By Kurt R. Karst