Israel’s Teva Pharmaceutical Industries is wasting no time in getting its generic version of Shire’s attention-deficit hyperactivity disorder blockbuster Adderall XR.

The Israeli drugmaker says that it has commenced commercial shipment of its generic Adderall XR(mixed amphetamine salts) in five doses, ranging from 5mg to 30mg. In August 2006, its subsidiary Barr Pharmaceuticals entered into a licence agreement with Shire as part of a settlement of patent litigation between the parties and was granted exclusive rights to sell the generic for 180 days from the date of commercial launch.

The arrival of generic competition is likely to hit Shire very hard seeing as how annual sales of Adderall XR in the USA were $1.5 billion in the for the twelve months ended February 28, based on IMS sales data. The UK firm is hoping that its new ADHD drug Vyvanse (lisdexamfetamine) will compensate for the loss of earnings and a deal was signed earlier this week with GlaxoSmithKline to co-promote the treatment for adults suffering from the disorder.

Generic Yaz approved
Teva also announced that the US Food and Drug Administration has approved its generic version of Bayer's oral contraceptive Yaz (drospirenone and ethinyl estradiol).

The Petach Tikva-headquartered group can launch the drug on July 1, 2011 or possibly earlier, under the terms of an agreement between Bayer and Barr. US sales of Yaz last year reached $616 million and the FDA approval means that once again Teva will have 180 days’ market exclusivity as it was first to file an Abbreviated New Drug Application.

Shire sues Natco
As for Shire, the firm has filed a lawsuit in the USA against India’s Natco Pharma for infringement of two patents on its kidney disease drug Fosrenol (lanthanum carbonate).

This case was filed in response to an ANDA filed by Natco seeking FDA approval to market generic versions of the drugs. Shire, which has also filed lawsuits concerning the drug against Teva and Mylan, said it has a “robust patent estate and is confident that it will protect the Fosrenol franchise”.