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Is Corcept’s new Korlym lawsuit a game-changer against Teva?

Zachary Silbersher

Corcept Therapeutics ($CORT) recently filed a new lawsuit against Teva ($TEVA) related to Teva’s proposed generic for Korlym®.  The new suit asserts three new patents that were recently listed in the Orange Book.  Are the three new patents a game-changer?

The patents include U.S. Patent Nos. 10,166,242 (“the ‘242 patent”), 10,166,243 (“the ‘243 patent”) and 10,195,214 (“the ‘214 patent”).  The ‘242 and ‘243 patents are directed to similar inventions, whereas the ‘214 patent is different.

The ‘242 patent and the ‘243 patent generally relate to methods of optimizing mifepristone levels in patients suffering from Cushings syndrome or hypercortisolism.  The patent claims require administering mifepristone, testing serum levels to determine mifepristone blood levels and then adjusting the dose of mifepristone to optimize a target blood level.  The patents also include the proviso that “the patient is not already suffering from a condition indicated for treatment of mifepristone.”

The ‘214 patent is directed to methods of reducing the dose of mifepristone for patients also taking a CYP3A inhibitor, such as ketoconazole.  More specifically, for patients taking 1200 or 900 mg of daily mifepristone, the dose is reduced to 600 mg per day for patients also taking a CYP3A inhibitor.   

            The ‘242 and ‘243 Patents 

The thing about the ‘242 and ‘243 patents is that they are directed to inventions similar to those claimed in patents already asserted in Corcept’s first lawsuit, namely, the ‘348 and ‘526 patents.  Similar to the ‘242 and ‘243 patents, the ‘348 patent is also directed to methods for optimizing mifepristone levels by testing serum levels to determine blood levels of mifepristone, and then adjusting the dose to achieve mifepristone levels above a target threshold. 

That means, of the six patents asserted by Corcept, four of them are generally related to the same purported invention.  That means that if any one of them suffers from defects of infringement or invalidity, that will likely read through to all four.

In the first lawsuit, Teva asserted an affirmative defense that assertion of the ‘348 patent was patent misuse.  As argued in its motion to dismiss, Teva contended in its affirmative defense that assertion of the ‘348 patent is frivolous because nothing within Teva’s proposed label for generic Korlym® indicates that it plans to instruct doctors to test serum levels and subsequently adjust dosages of mifepristone based upon those tests.

As expected, Teva’s Answer to Corcept’s second lawsuit, which was filed on March 1, 2019, contains a similar affirmative defense with respect to the ‘242 and ‘243 patents.  (See 18-3632, Dkt. 62 at 11).  Teva has alleged that Corcept’s assertion of the ‘242 and ‘243 patents constitutes  patent misuse, thus rendering those patents unenforceable.  Teva claims that the patents cover uses of mifepristone that are not approved indications for treatment by Korlym®, and therefore, they should not have been listed in the Orange Book.   

Moreover, the ‘348 patent recently suffered another setback outside of Corcept’s litigations against Teva.  In August 2018, Neptune Generics filed a petition for inter partes review that challenged all claims of the ‘348 patent as invalid.  That IPR was instituted on February 15, 2019.  Given the similarities among the patents, if the ‘348 patent is eventually invalidated in the IPR, that will likely read through to the ‘526 patent as well as the ‘242 and ‘243 patents.   

The IPR is not simply Neptune’s game.  Teva can join Neptune’s IPR, but it will have to do so within 30 days of the institution decision.  Teva’s incentive to join the IPR is that, if Neptune drops out or reaches an agreement with Corcept, Teva can nevertheless keep the IPR going.  It will be interesting to watch if Teva joins the IPR within the next week or so. 

Thus, given the similarities among the patents, the addition of the ‘242 and ‘243 patents is unlikely to be a game-changer.  The first and second lawsuits have been consolidated.  That may add marginal delay.  Yet, the fact is that the first lawsuit had not progressed that far to date in light of Teva’s failed bid to dismiss the case.  Moreover, the Final Written Decision for the IPR of the ‘348 patent is scheduled to issue by February 2020.  This may, in fact, help Teva expedite resolution of the ‘348, ‘526, ‘242 and ‘243 patents.

            The ‘214 Patent

Whereas the ‘242 and ‘243 patents do not appear to be game-changers, the ‘214 patent is different.  This patent is directed to a use that is potentially covered by Korlym®’s label.  The Korlym® label includes a warning for patients taking Korlym® with strong CYP3A inhibitors, such as ketoconazole.  Thus, among the six patents currently asserted by Corcept against Teva, the ‘214 patent is arguably the first that is at least facially covered by the Korlym® label.

Indeed, Teva’s Answer to the second lawsuit did not include any affirmative defenses alleging that Corcept’s listing of the ‘214 patent in the Orange Book or assertion against Teva constituted patent misuse.  The ‘214 patent is thus the only patent asserted by Corcept that Teva has not yet claimed to be frivolous.

The current Korlym® label indicates that for concomitant administration of Korlym® with CYP3A inhibitors, such as ketoconazole, the dose of mifepristone should be limited to 600 mg per day.  On its face, that appears relatively consistent with the ’214 patent, which requires limiting the dose of mifepristone to 600 mg per day in conjunction with certain CYP3A inhibitors.  Notably, the older Korlym® label indicated that when taken with a CYP3A inhibitor, the daily dose of mifepristone should be limited to 300 mg.  The label appears to have been amended following a phase 1 clinical study regarding concomitant use of mifepristone and ketoconazole, which is also described within Example 3 of the ‘214 patent.

 All that said, Corcept is not guaranteed to prevail on the ‘214 patent.  Teva is still likely to challenge the validity of the ‘214 patent, as well as attempt to construe the patent in a way that it will argue shows non-infringement as well.  It is still far too early for Teva to have set for the bases for those defenses.  We will likely see the contours of those arguments emerge during the claim construction process, which is likely to occur later this year. 

            Did Corcept’s tactic work? 

As will be recalled, when Teva originally filed its ANDA for Korlym®, the ‘214 patent had not yet issued.  Indeed, Corcept filed the patent application for the ‘214 patent only about six months before Teva filed its ANDA.  Corcept put the patent application on fast-track at the Patent Office, which appears to have been a tactical decision knowing that an ANDA could be filed shortly.  If Corcept’s strategy was to delay Teva’s entry long enough so that it could get the ‘214 patent to issue, and then assert it against Teva, that strategy appears to have worked, at least for now. 

Corcept is now in a position where, more than a year after Teva filed its ANDA, it is just starting a patent case against Teva with a patent that has some potential grounding of infringement in its label.  Even if only the ’214 patent were asserted against Teva, a one-patent case could still take a couple of years to resolve.  That buys Corcept time to essentially beef up its pipeline, and reduce the threat of an eventual generic entry for Korlym®. 

Moreover, the likelihood of Corcept actually prevailing on the ‘214 patent appears much higher than for the other patents.  Keep in mind, a brand manufacturer technically only needs to prevail on a single patent to be awarded an injunction against a generic until expiration of that patent.  Here, the ‘214 patent does not expire until 2037.  An injunction against Teva’s generic until expiration of the ‘214 patent essentially guarantees monopoly pricing for infinity (or a time-horizon much longer than that of most investors.)

On the other hand, allegations of patent misuse are no joke.  They are not tossed around lightly, and you don’t typically see these types of allegations in every Hatch-Waxman case as a matter of course.  Teva’s ANDA received tentative approval in October 2018.  That means, had Corcept not previously asserted the ‘348, ‘495 or ‘526 patents, then Teva could have launched several months before this second lawsuit.  If Teva’s allegations are true, then Corcept essentially kept Teva out of the market by asserting frivolous allegations for patents that never should have been listed in the Orange Book. 

Whether or not that type of tactic is kosher remains to be seen.  Whether that type of tactic will eventually blow-back onto Corcept cannot yet be ruled out.  For now, however, the case moves on.