CENTER FOR DRUG EVALUATION AND RESEARCH

APPLICATION NUMBER: 22-037

CLINICAL PHARMACOLOGY AND BIOPHARMACEUTICS REVIEW(S)

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BIOPHARMACEUTICS REVIEW NDA# 22037 Drug Guanfacine, IntunivR Formulation Extended Release tablets 1, 2, 3 and 4 mg Type NDA resubmission Sponsor Shire Pharmaceuticals Inc Letter Date January 26 2009 Reviewer/Team Leader Patrick Marroum, Ph.D. ________________________________________________________________________ Background: Shire Pharmaceuticals is resubmitting this application to seek approval of a new formulation of guanfecine for the treatment of attention deficit hyperactivity disorder (ADHD. In the approvable letter dated June 20, 2007,

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RECOMMENDATION The Office of New Drug Quality Assessment has reviewed the new dissolution method submitted to the Agency and finds that the proposed dissolution method is acceptable and recommends that the dissolution method and specifications be as follows: USP apparatus II at 75 rpm Medium: pH 2.2 HCl buffer 1 hour: % 4 hours: % 8 hours: %

not less than % Please convey the above recommendation to the sponsor __________________________ Date________________ Patrick Marroum, Ph. D. Office of New Drug Quality Assessment cc: Baweja

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---------------------------------------------------------------------------------------------------------------------This is a representation of an electronic record that was signed electronically andthis page is the manifestation of the electronic signature.--------------------------------------------------------------------------------------------------------------------- /s/---------------------Patrick Marroum5/15/2009 02:40:29 PMBIOPHARMACEUTICS

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24 Page(s) has been Withheld in Full immediately following this page as B4 (CCI/TS)

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11 pages withheld immediately after this page as (b)(4) draft labeling.

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/s/Elena Mishina6/4/2007 11: 16: 54 AMBIOPHACEUTICS

Patrick Marroum6/4/2007 11: 28: 07 AMBIOPHACEUTI CS