The British drugmaker has already filed lawsuits in the US District Court of Delaware against three other Indian pharmaceutical companies Glenmark Pharmaceuticals, Aurobindo Pharma and Wockhardt. Apart from Indian companies, AstraZeneca is also suing US-based Actavis and Amneal Pharma on similar grounds.
While the lawsuits against Glenmark, Wockhardt and Aurobindo were filed on May 23, Sun Pharma's application to make a generic version of Onglyza was challenged through a lawsuit dated June 6.
AstraZeneca holds two patents on Onglyza, according to data from the US Food and Drug Administration (USFDA). One of the patents is set to expire on November 30, 2028 while the other will expire on July 31, 2023.
AstraZeneca has another novel drug for diabetes called Kombiglyze XR. Sun Pharma, and its US subsidiary Caraco Pharma, had also sought to manufacture a generic version of this drug by challenging a patent held by AstraZeneca, which is set to expire in July 2025. In the lawsuit, AstraZeneca has also attempted to thwart Sun Pharmas attempt to have this patent overturned.
The Indian pharma companies are contending that though the generic drugs will be bioequivalent to Onglyza, the patents held by AstraZeneca are invalid, unenforceable and/or will not be infringed by the sale of the generic version.
Sun Pharma declined to comment while emails sent to Wockhardt and Glenmark on Wednesday didnt elicit any response.
AstraZeneca is pleading to stop the Indian companies from marketing the generic drug and also for recovery of potential damages if the companies market it before the formers patents expire.
The drug was initially jointly marketed by AstraZeneca and Bristol-Myers Squibb (BMS). In February, US-based BMS sold its diabetes business to AstraZeneca, along with rights to the drug in question. Onglyza earned $378 million in 2013 for AstraZeneca, a 17% increase over previous year.
Bloomberg consensus estimates suggest the drug is set to net more than $1 billion in revenues in 2015, which would make it a potential blockbuster therapy. A drug is called a blockbuster when its sales cross $1 billion.
There are more than 347 million diabetes patients globally and the market for anti-diabetic medicines is estimated at $43.5 billion.