Indivior's New Suboxone Patent Cannot Keep Dr. Reddy's Generic Off Market

US Federal Circuit applies new standard in finding continuation patent claims are indistinct from those in parent patent, vacates preliminary injunction.

Indivior PLC struck out in its attempt to keep a generic version of its Suboxone sublingual film (buprenorphine/naloxone) off the market, as an appeals court concluded that a new patent covering the method used to make the film was essentially the same as an earlier invalidated patent.

In a 2-1 decision issued Nov. 20, the US Court of Appeals for the Federal Circuit vacated a preliminary injunction enjoining Dr. Reddy's Laboratories Ltd. from selling generic buprenorphine-and-naloxone-containing transmucosal film products and remanded the case to the district court. The injunction, issued in July, followed a temporary restraining order which forced Dr. Reddy's to halt sales of its generic soon after it launched.

The Federal Circuit stated that the district court's conclusion that Indivior was likely to succeed on the merits in its patent infringement suit against Dr. Reddy's was based on an erroneous interpretation of the scope of patent claims. The appeals court reached the opposite conclusion, finding Indivior has not shown that it is likely to succeed on the merits of its infringement claim.

Dr. Reddy's said in a release that it will resume its launch activities "as soon as permitted."

Indivior said in its release that it expects Dr. Reddy's to reenter the market after the appeals court issues a mandate, a formal filing returning the case to the district court. It said any sales in the US would be on an "at-risk" basis, subject to the outcome of the appeal of noninfringement judgments on two patents and ongoing litigation against Dr. Reddy's asserting recently-granted Orange Book-listed patents. Indivior said it would file a petition for both a panel rehearing and rehearing en banc of the ruling vacating the preliminary injunction.

Suboxone film, a treatment for opioid dependence, was approved by FDA in 2010 and replaced a tablet formulation. The company also markets Sublocade (buprenorphine extended-release) injection, which was approved in 2017.

The Federal Circuit's decision is significant as it gives Dr. Reddy's a leg up in litigation with Indivior and makes its "at-risk" launch less risky.

Kevin Martin, a partner at Goodwin Procter who represented Dr. Reddy's before the Federal Circuit, said that based on the ruling, it would be difficult for Indivior to prevail in its infringement suit.

Martin noted that preliminary injunctions are vacated infrequently, about a couple of times a year by the Federal Circuit. He said this case appears to be the first in which the Federal Circuit applied the standard it set earlier this year in SimpleAir Inc. v. Google LLC to find that the claim in the second Indivior patent was not sufficiently different from that in the parent patent.

Different Drying Techniques

Indivior filed the complaint alleging infringement of patent No. 9,931,305 on April 3, the day the patent issued. The patent is a continuation of patent No. 8,693,514. In August 2017, the Delaware district court found that Dr. Reddy's did not infringe the '514 patent claims.

The Federal Circuit notes that after this ruling, Indivior amended claims in its then-pending '305 patent application and filed a terminal disclaimer to overcome obviousness-type double patenting rejections based on the claims of the '514 patent. The terminal disclaimer informed the US Patent and Trademark Office that the termination date of the '305 patent would be the same as the '514 patent.

Both patents disclose methods of producing films that have uniform drug content. The methods generally involve mixing a pharmaceutically active ingredient with a polymer in a solvent, casting the mixture onto a planar carrier surface to form a wet film, and then drying the film to produce a solid sheet that can be cut into individual dosage units. The patent specification discloses controlled drying techniques that avoid the "rippling" problems of conventional drying methods to produce content-uniform film.

In granting the preliminary injunction, the US District Court for the District of New Jersey found that Indivior was likely to show that the '305 claims are not "patentably indistinct" from the '514 claims. Thus, the court said, it would likely show that its suit was not barred by claim preclusion (which prevents a plaintiff from bringing successive lawsuits on essentially the same claims) under the Federal Circuit's SimpleAir v. Google decision.

Claim Language But Not Scope Changed, Federal Circuit Finds

But the Federal Circuit concluded that the '305 claims do not cover the conventional top air drying method to produce films, which is what Dr. Reddy's uses.

"The patent distinguishes these conventional methods from the present invention and disparages their use, stating that these methods result in films that do not have content uniformity – a key feature of the invention," the court states.

While the language of the claim terms in the '305 patent changed from those in the '514 patent, "the scope of the patents did not materially change," the court stated. "The claims of the '305 patent are thus 'patentably indistinct' from those of the '514 patent."

In addition, the court said Indivior's filing of a terminal disclaimer is a "strong clue" that the claims of the two patents are not patentably distinct.

Patent Covers Film, Not Drying Method, Judge Newman Says

Judge Pauline Newman dissented. She said her colleagues did not consider the district court's conclusion that the balance of harms appears to favor Indivior but instead made findings of the merits of infringement, although there has been no trial of infringement.

"My colleagues erroneously apply a decision of the district court in Delaware on a different patent with different claims, although that decision is pending on appeal," she stated.

Newman said the invention claimed in the '305 patent is not a drying method but a film for transmucosal administration of an active ingredient. She stated that the '305 patent was amended to present claims that are not limited to any drying method.

Mylan Generic Expected To Launch Soon

FDA approved Dr. Reddy's and Mylan NV abbreviated new drug applications for generic versions of Suboxone film on June 15. Mylan settled patent litigation with Indivior in September 2017 under undisclosed terms. Indivior also settled patent litigation with Par in May 2018 and announced that the agreement permits Par to begin selling a generic version of Suboxone on Jan. 1, 2023, or earlier under certain circumstances. (Also see "Dr. Reddy's Launches First Generic Suboxone Film; Indivior May Seek Injunction" - Scrip, 17 Jun, 2018.)

Jefferies equity analyst Piyush Nahar said in a Nov. 20 note that he expects Mylan to launch soon and Alvogen Inc. and Par Pharmaceutical Inc. to enter in fiscal year 2020. Teva Pharmaceutical Industries Ltd. also has a pending ANDA and Indivior is expected to launch an authorized generic. (Also see "US Suboxone Win Lifts Dr Reddy’s As Embattled Indivior Fights On " - Scrip, 21 Nov, 2018.)

The Suboxone ANDA filings have elicited a separate legal battle with FDA as the agency adopted a new definition of "first applicant" in reviewing the applications. FDA concluded that a sponsor does not lose the status of first applicant by failing to provide timely notice of Paragraph IV certification to the brand manufacturer. As first applicant, a sponsor is eligible for 180-day marketing exclusivity.

Teva filed suit against FDA to eliminate this new policy, which has ramifications for its ability to obtain 180-day exclusivity for its generic version of Allergan PLC's Restasis (cyclosporine). (Also see "Teva Sues US FDA To Obtain 180-Day Exclusivity For Its Generic Restasis" - Pink Sheet, 18 Oct, 2018.)