Amerigen Pharmaceuticals, Ltd and Alembic Pharmaceuticals Limited are challenging the claims of U.S. Patent No. 6,858,650 as being obviousness under 35 U.S.C. § 103(a).  Amerigen and Alembic each filed their own petition and seek to join in the IPR of Mylan Pharmaceuticals, Inc.et al. v. UCB Pharma GmbH, Case IPR2016-00510, which the Patent Trial and Appeal Board (PTAB) has already issued its Decision instituting Inter Partes Review (IPR) in January, 2016. The PTAB said in its decision that UCB Pharma GmbH’s patents, licensed to Pfizer for Toviaz, are likely obvious because the compounds used are too similar to Pfizer’s drug Detrol. TOVIAZ® (fesoterodine fumarate) succeeded DETROL ® (tolterodine tartrate) as the company’s branded incontinence treatment.

Patent at Issue:

U.S. Patent No. 6,858,650 (“Stable salts of novel derivatives of 3,3-diphenylpropylamines,” issued February 22, 2005).

Claim 1: Generic structure for the covered molecules: derivatives of 3,3-diphenylpropylamines

Claims 2-5: Specify the type of compatible acid, specify chirality, and specify substitutions and salt forms.

Claim 5: R-(+)-2-(3-(diisopropylamino- 1-phenylpropyl)-4-hydroxymethyl-phenyliobutyrate ester hydrogen fumarate (commonly referred to as fesoterodine fumarate).

Claims 21-24: recite methods of use.

http://www.patentdocs.org/2016/09/ptab-life-sciences-report-1.html

http://www.law360.com/articles/820997/mylan-wins-ptab-review-of-pfizer-s-toviaz-patents