Patent Win Protects Eisai's Aricept Against Teva's Potential Generic Product Launch Via Preliminary Injunction

Implications: * As noted in the Wall Street Journal article, Aricept® is a blockbuster drug for the treatment of Alzheimer's disease.  And, as noted in Judge Ackerman's ruling, Aricept sales are a huge source of Eisai's revenue - "sales of Aricept® in the United States constitute 70% of Eisai’s U.S. subsidiary’s profits, and 25% of Eisai’s revenues worldwide". * In patent infringement litigation at a Federal trial court, a preliminary injunction in favor of Eisai and against Teva has just been granted which orders Teva not to sell generic Aricept® as claimed in US Patent 4895841. * The Fri 28 Mar 2008 26-page Opinion & Order (Doc #191) by Judge Harold A. Ackerman of the United States District Court for the District of New Jersey grants Eisai's Motion for Preliminary Injunction (Doc #141).

Analysis:
As always in Life Science Patent Battles, the details of this particular dispute, at this particular point in the litigation timeline, are critical.  With that in mind, a closer examination of the present context is warranted.

Prior filings established that Teva's generic drug [i.e., its generic variant of Aricept® under Teva's ANDA/Abbreviated New Drug Application which the FDA had tentatively approved in January, 2008] would infringe Claims 8, 10, and 13 of US Patent 4895841.  Other filings established that the only remaining attack upon the '841 Patent was that, due to alleged inequitable conduct, it should be determined to be unenforceable.  At least up through this point, Teva has failed in this remaining attack.

Upon the April, 2008 expiration of the 30-month Hatch-Waxman stay, the prior FDA tentative approval of Teva's ANDA could then be made a final approval, and, at that point, Teva would be free to engage in an "at-risk" launch of its generic product.  Clearly, from Eisai's perspective, preventing Teva's at-risk launch is of the utmost importance.

The Preliminary Injunction effectively achieves Eisai's #1 goal in stopping Teva's launch.