FDAnews Drug Daily Bulletin


Dec. 22, 2005

Shire said recently that the trial for its patent suit against Barr Laboratories over attention-deficit/hyperactivity disorder (ADHD) drug Adderall XR had been delayed, which may give Shire more time to promote its abuse-proof Adderall XR follow-on, NRP104, without generic competition. Adderall XR is Shire's top-selling drug, with 2004 sales of $606.7 million.

British drugmaker Shire said the court had continued a recent pre-trial conference until March 10, 2006, and had not set a trial date. The Shire-Barr trial — initially scheduled for January 2006 — could be delayed well into next year, and a ruling seems unlikely before the end of 2006, analysts said, giving Shire more time to steer patients to NRP104.

With NRP104, Shire and drug development partner New River Pharmaceuticals aim to tap a growing market for abuse-proof ADHD stimulant drugs. ADHD stimulant drugs are abused recreationally and also by students who take them to enhance concentration. Study results unveiled recently confirmed that NRP104 is more abuse-proof and overdose-proof than other amphetamine-based ADHD therapies like Adderall XR (amphetamine aspartate/ amphetamine sulfate/dextroamphetamine saccharate/dextroamphetamine sulfate).

Moreover, any deal Barr strikes with Shire is also likely to delay generic competition beyond 2006, analysts said. Such a delay could boost Shire's earnings per share 64 percent to 67 cents a share, Merrill Lynch analyst Graham Parry writes in a recent note.

Shire has also thrown up other hurdles to generic competition by suing rivals for infringing on its newest patent, and filing a citizen petition with the FDA requesting that any abbreviated new drug applications show "exact bioequivalence" to Adderall XR, notes Merrill Lynch analyst David Munno.

In a more negative scenario, however, Barr could cut a deal with Impax or another generic drugmaker that has also filed to market a version of Shire's drug, if that drugmaker wins its case against Shire. Impax's trial is set for February 2006. Barr could also launch generic Adderall XR at-risk before the trial begins.