A federal appeals court ruling in a case pitting drugmakers Apotex and Teva Pharmaceutical against one another could make it harder for generic firms to file lawsuits intended to trigger -- or avoid triggering -- marketing exclusivity periods.

The ruling issued by U.S. Court of Appeals for the District of Columbia Circuit affirmed a lower court's decision to deny Apotex's request for a preliminary injunction blocking Teva Pharmaceutical's launch of a version of Bristol-Myers' Squibb's cholesterol drug Pravachol. Annual brand product sales of Pravachol (pravastatin sodium) in 10-, 20- and 40-mg strengths were approximately $1.5 billion in 2005, according to Teva.

Apotex had sought the injunction in April after the FDA reversed its decision upholding the drugmaker's assertion that a lawsuit between it and BMS has triggered Teva's exclusivity period to market Pravachol. In the Apotex-BMS dispute, the court dismissed the case, which Apotex said qualified as a court order that triggered Teva's exclusivity. In March, the U.S. Court of Appeals for the District of Columbia sent the issue back to the FDA to explain its reasoning in its decision that the exclusivity period had been triggered. In its revised decision, the FDA said the ruling in fact could not trigger exclusivity because the court did not address whether the patent was invalid, not infringed or unenforceable.

A key element of the ruling was the court's acceptance of the FDA's determination that only a court decision showing that a determination that a patent was invalid, not infringed upon or unenforceable had been made by the court would trigger a generic drugmaker's marketing exclusivity period.

The FDA had argued in its determination that forcing the agency to look beyond the face of a court order -- in other words, to examine an order that doesn't explicitly state invalidity, noninfringement or unenforceability -- would require it to make judgments about patent law that it is not qualified to make. Encouraging "highly-interested and well-financed litigants to pursue ever-finer distinctions, ever farther removed from the language of the statute and from its purposes offers no guarantee of more rapid generic drug approvals, only a high likelihood of delay due to litigation," the agency argued.

The FDA also argued that uncertainty about the type of court decision that triggers marketing exclusivity could undermine marketplace planning and interfere with business planning and investment.

"In our view, these perfectly reasonable propositions adequately support FDA's position," the appeals court said. (http://www.fdanews.com/did/5_111/)