A federal appeals court affirmed a lower court’s decision to reject a patent challenge to Eli Lilly antipsychotic drug Zyprexa (olanzapine). The decision means Zyprexa, Lilly’s biggest seller, won’t face generic exposure until the scheduled patent expiry in 2011. The Ivax unit of Teva Pharmaceutical Industries and Dr. Reddy’s Laboratories had claimed a US District Court was mistaken in upholding the drug’s patent. One of their arguments was that clinical trials of olanzapine constituted a public use and therefore should bar Lilly from getting a patent. The Court of Appeals for the Federal Circuit in Washington, DC, disagreed, ruling the patent valid and enforceable. The appeals court, in a 23-page opinion released Tuesday, also said Lilly had not committed fraud by withholding information from the patent office, which Teva and Dr. Reddy’s had suggested. The ruling “not only affirms the validity of our patent, but upholds patent law that helps enable the significant investments required to develop the next generation of revolutionary medicines for the patients who need them,” Lilly CEO Sidney Taurel said in a statement. Lilly also is defending its marketing of Zyprexa in lawsuits by attorneys general of Mississippi, Louisiana, West Virginia and Alaska alleging the company promoted it for unapproved uses and hid the risks of weight gain and diabetes. Lilly received a subpoena in September from the California AG related to Zyprexa promotion and remuneration of healthcare providers. Last month The New York Times accused Lilly of keeping information about Zyprexa’s links to obesity and diabetes away from doctors. The allegations were based on documents given to the newspaper by a lawyer representing mentally ill patients. Lilly defended Zyprexa’s safety and called the release of the documents illegal. Zyprexa, which had 2005 US sales of $2.5 billion, was America’s best-selling antipsychotic in 2004 but was edged out by AstraZeneca’s Seroquel last year, according to IMS Health.