InSite Vision Incorporated announced that it will join Merck known as MSD outside the United States (US) and Canada, and Pfizer Inc. in filing a patent infringement lawsuit against Sandoz Inc.

Sandoz recently filed an Abbreviated New Drug Application (ANDA) with the US Food and Drug Administration (FDA) seeking to market a generic version of AzaSite (azithromycin 1% ophthalmic solution) before expiration of the patents covering AzaSite and its use. AzaSite is marketed by Inspire Pharmaceuticals in the US, now a wholly-owned subsidiary of Merck.

The companies have agreed that Merck will take the lead in prosecuting this lawsuit. Each company will be responsible for their own legal costs, with InSite assuming a monitoring role.

Sandoz filed an ANDA application for AzaSite with the FDA of which InSite received notice on April 18, 2011, and InSite has 45 days to file a patent infringement lawsuit. With this filing today, that time requirement has been met. This lawsuit also triggers an automatic stay, or bar, of the FDA's approval of the ANDA for up to 30 months or until a final court decision of the infringement lawsuit, whichever comes first.

Merck, with the assistance of InSite and Pfizer, will vigorously defend the five US patents related to AzaSite. InSite owns four US patents covering AzaSite and its use, and an exclusive license to a Pfizer-owned azithromycin patent. Under the license agreement between InSite and Inspire, Inspire has the exclusive use of these patents in the US in return for a 25 per cent net sales royalty from AzaSite sales. InSite believes that its four patents and the Pfizer patent were properly prosecuted with the US Patent and Trademark Office (USPTO) and are valid, and will provide AzaSite exclusivity until March 2019.

Additionally, InSite recently received a USPTO ruling that the AzaSite patent interference brought by the University of California at San Francisco (UCSF) against InSite patents will proceed to the Priority Phase, or trial phase.

In September 2010, the USPTO heard brief oral arguments where each side presented motions, including motions to dismiss, to be considered by a panel of USPTO judges. In this ruling, the panel of judges decided to see all evidence supporting the inventorship and priority before making a final decision. The USPTO has also determined that all evidence should be submitted, and final oral arguments completed before the end of 2011.

Approximately 90 percent of such cases are decided at the priority phase rather than in oral arguments in the Motion Phase. InSite continues to believe that the evidence supporting the inventorship and priority strongly supports the company in this matter, and InSite will continue to vigorously defend its position.

InSite Vision is committed to advancing new and superior ophthalmologic products for unmet eye care needs.