Hyderabad-based drugmaker Dr Reddy?s Labs has been sued by the largest Japanese pharma firm, Takeda Pharma, in the US for allegedly infringing upon its patent coverage of gastroesophageal reflux disease drug Dexilant (Dexlansoprazole Delayed Release Capsules).

The drug has an annual market size of over $300 million in the US market. Annual sales of Dexilant delayed release capsules (60 mg), in the US stood at about $300 million for the 12 months ended December 31, 2010, according to IMS Health.

Alternately, Wolters Kluwer Health estimates peg the US sales of the drug?s strength ? 30 mg and 60 mg ? at $20 million and $261 million, respectively, for the current 12 months ending January 2011. More importantly, this drug which was launched in February 2009 in the US, under a different brand name Kapidex, is positioned as the successor to the peptic ulcer treatment Prevacid (lansoprazole), which has been one of Takeda?s international strategic products with a market size of $700 million in the US market alone. Interestingly, Dr Reddy?s has already commercialised a generic version of Prevacid in US late last year.

Dexilant is in a class of medications called proton pump inhibitors which have an annual market in the US in excess of $13 billion and works by decreasing the amount of acid made in the stomach. Of the patents granted to the drug innovator for Dexilant, the earliest is scheduled to expire not before 2020. ?As a matter of company policy, we do not comment on patent litigation issues when they are subjudice,? a Dr Reddy’s company spokesperson told FE. However, at this point of time, it is not clear whether Dr Reddy?s qualifies for the first to file status for this particular drug, which may entitle it to 180 days of generic market exclusivity, should FDA approve its abbreviated new drug application (ANDA) and the firm defends its case successfully in judiciary to either prove that its ANDA doesn’t violate Takeda’s patents or alternately nullifies the patent of the drug innovator in courts.

Meanwhile, not only has another top US generic drugmaker Impax Labs confirmed early this month that it has been sued by Takeda for the same drug in the Northern District of California (Dr Reddy’s has been sued in the southern district of New York), it also announced that ?Based on the filing date of the ANDA, the company believes that it is the first to file an ANDA with a paragraph IV certification on the 30 mg capsule, and expects to be entitled to 180 days of market exclusivity.? Similar claims have been made by another California-based specialty pharma firm Handa Pharma last month. Lately, in most cases, first to file status is being shared by more than one generic player. As per available statistics, gastrointestinal (GI) disorders are set to affect over 300 million people across the globe by 2012. As generations of people become obese and consume increasingly poor diet, the number of people suffering from these disorders are expected to surge manifold.

(With inputs from BV Mahalakshmi)