Barr Laboratories has initiated a patent challenge for Focalin XR (dexmethylphenidate hydrochloride) extended-release capsules 5mg, 10mg, 15mg, and 20mg, which are indicated for the treatment of Attention Deficit Hyperactivity Disorder (ADHD) in patients aged six years and older. Barr filled an Abbreviated New Drug Application (ANDA) containing a Paragraph IV Certification for a generic version of Novartis' Focalin XR in June, which was duly accepted for filing by the US Food and Drug Administration (FDA) in October. On November 16, Elan Corporation and Elan Pharma International, involved in the US manufacture of Focalin XR for Novartis, filed suit in the US District Court for the District of Delaware to prevent Barr from proceeding with the commercialisation of its product. Focalin XR has sales of approximately $252m in the US. The European Patent Office has ruled that AstraZeneca's European patent for a multiple unit pellet tablets (MUPS) formulation (EP 723 437), used in the company's drugs Nexium (esomeprazole magnesium) and Losec (omeprazole), was still valid. In June 2005 the patent was challenges by four generic drug makers, Hexal (Germany), Ratiopharm (Germany), Teva Pharmaceuticals Industries (Israel), and unit of Novartis (France). The positive decision means the patent covering a multiple unit tablet is still valid until 2015 in Austria, Belgium, Switzerland, Germany, Denmark, Spain, France, UK, Greece, Ireland, Italy, Liechtenstein, Luxembourg, Monaco, The Netherlands, Portugal, Sweden, Latvia, Lithuania and Slovenia. MUPS formulation comprises a proton pump inhibitor compound. "AstraZeneca has a comprehensive intellectual property portfolio protecting MUPS formulations as well as the products Nexium and Losec. More importantly, the intellectual property portfolio protecting Nexium includes additional patents with expiration dates ranging from 2009 through to 2018," AstraZeneca said in a statement. Patents are also being challenged in the US, but as yet, no trial date has been set. Endo Pharmaceuticals and Penwest Pharmaceuticals have filed a lawsuit against Impax Laboratories in the US District Court for the District of Delaware in connection with Impax' ANDA for Opana ER (oxymorphone HCL) extended-release tablets CII indicated for the treatment of moderate to severe pain. Endo and Penwest assert a series of Paragraph IV Certification Notices were wrongfully served by Impax on Endo and Penwest. The notices advised that Impax had submitted to the FDA an ANDA seeking approval to market generic versions of all four dosage strengths of Opana ER. The lawsuit against Impax alleges the infringement of certain US patents that cover the Opana ER formulation. The lawsuit also seeks declaratory judgement that Impax has no legitimate basis to trigger patent litigation as Impax has announced the FDA rescinded its acceptance of its ANDA. The companies also seek the court to declare the Paragraph IV Certification served on Endo and Penwest were null, void and of no legal effect. "We believe that our Paragraph IV certification for generic Opana ER was proper, that our product does not infringe any valid, enforceable patent, and, as such, we will vigorously defend this lawsuit. Furthermore, we believe that the rescission of our ANDA by the FDA was inappropriate and we are continuing to work with the FDA to allow our ANDA to stand," Impax president and chief executive Dr Larry Hsu said in a statement. According to Endo and Penwest, Opana ER has been granted new dosage exclusivity until June 22, 2009. Ranbaxy Laboratories and Astellas Pharma/Boehringer Ingelheim Pharmaceuticals have agreed to stipulate a dismissal of the pending US litigation in regards to US Patent No. 4,703,063 for Flomax (tamsulosin HCL) capsules. Flomax, also known as Harnal in Japan, is indicated for the treatment for the functional symptoms of benign prostatic hyperplasia. As a result of the settlement, the case has been dismissed without prejudice. Under the agreement, Ranbaxy has the opportunity to launch a generic version of Flomax in the US market as of March 2, 2010, eight weeks prior to the expiration of the paediatric exclusivity, if such is granted by the FDA. Other details in regards to the settlement were not disclosed.