Shire reported new clinical data for its new attention deficit hyperactivity disorder drug NRP104 yesterday, suggesting that it is effective treating the condition in six to 12 year-olds and appears to be at least as effective as Shire’s current Adderall XR product.

NRP104 (lisdexamfetamine dimesylate), developed with New River Pharmaceuticals, is one of a number of new ADHD products Shire is developing to reduce its reliance on Adderall XR (mixed amphetamine salts), currently its best-selling product with sales of $730 million last year but which is facing generic competition in the USA.

The new compound, which has been tipped to become a blockbuster product, is a pro-drug of amphetamine that promises to offer the efficacy of its parent without the potential for abuse. Diversion and overdose toxicity. Shire is hoping to migrate Adderall users to the new product before generic copies of the drug get a stranglehold on the market.

In the Phase III study, 30mg, 50mg, and 70mg doses of NRP104 demonstrated significant improvements in average ADHD symptoms compared with placebo after four weeks of once-daily treatment. The average reduction in symptoms according to the ADHD Rating Scale (ADHD-RS) was 51%, 54% and 59%, respectively, for the three doses.

Shire noted that improvements seen in the first week of treatment, and the trial showed that a morning dose provided cover right through the school day and into the evening.

Meanwhile, the Phase II trial found that NRP104 performed as well as Adderall XR on classroom assessment tools designed to assess academic productivity. In terms of efficacy there was little to differentiate the two active treatments – both were significantly superior to placebo. Adverse events were mild to moderate, according to Shire.

Separately, New River said it started a late-stage clinical trial of tNRP104 in adult ADHD patients. It aims to file for approval in this population in the second quarter of 2007 if the results are positive.

Shire also reported positive trial results for another of its ADHD products, the transdermal patch product Daytrana (methylphenidate), showing that it was effective in reducing ADHD symptoms in children aged six to 12, and was generally well-tolerated.

Daytrana was approved for marketing in the USA in April and is due for launch this summer. It is the first non-oral medication cleared for ADHD.

New data on SPD476

Meanwhile, Shire has also reported new data on its ulcerative colitis drug MMX-mesalamine (SPD476), showing that it can induce remission in patients with active mild-to-moderate disease.

The company also said that the product, which has already been submitted for approval in the USA and Europe, was well-tolerated in both once-daily and twice-daily dosing. As a once-daily product, SPD476 could be a strong contender in the world market for mesalamine products used for ulcerative colitis, currently valued at around $1.6 billion a year, as most current products based on this drug require multiple tablets to be taken each day.

Shire filed for approval of the new product, under the trade name Mesavance in the USA last December, and followed this up with a submissions in Europe and Canada earlier this year.