The court of appeals for the federal circuit has upheld a preliminary injunction granted by the US district court of New Jersey barring Ranbaxy [ Get Quote ] Pharmaceuticals Inc, a subsidiary of Ranbaxy Laboratories, from marketing Quinapril HCI tablets (5,10,20, and 40 mg).

According to a release issued by Ranbaxy to the Bombay Stock Exchange [ Images ] on Tuesday, the company had appealed to the CAFC to reverse a preliminary injunction as a result of a suit brought by Pfizer [ Get Quote ] Inc asserting that RPI's Quinapril HCI tablets did not infringe on US Patent No 4,743,450 literally and under the doctrine of equivalents.

"The merits of the principal case will now be argued at the district court in New Jersey where a trial will be held on the merits of the company's non-infringement case," the release added.

AstraZeneca sues Ranbaxy over Nexium

Quinapril HCI tablets are the AB-rated generic equivalent of Pfizer's anti-hypertensive agent Accupril tablets, the release said.

Jay Deshmukh, vice president (global intellectual property) of Ranbaxy, said, "The appeals court explained that its decision was based on a preliminary record and noted that claim construction, a legal issue, is subject to change based on a more developed factual record."

"Moreover, the preliminary injunction did not address the invalidity or enforceability of the '450 patent. Accordingly, Ranbaxy intends to vigorously challenge infringement, validity and enforceability of the patent in further proceedings before the district court," he added.