Indianapolis-based Eli Lilly and Co. has failed to win an appeals court rehearing over its loss of patent protection for the cancer drug Gemzar.

The U.S. Court of Appeals for the Federal Circuit today, in a notice posted Monday morning on the court’s website, said it denied a request for a rehearing before the original panel or for a hearing before the entire court.

Without an appeal, generic drugs are now poised to wipe away most of Lilly’s $750 million in annual U.S. revenue from the drug. Gemzar is approved to treat ovarian, breast, pancreatic and non-small-cell lung cancers.

Lilly had asked the appeals court to reconsider its decision rendered in July, which upheld an August 2009 ruling against Lilly’s patent claims by a federal court in Michigan.

Lilly had claimed that its patent on its method of using Gemzar to treat cancer should protect the drug until 2013. But that patent was ruled invalid, meaning that Lilly’s only valid patent on Gemzar is its composition-of-matter patent on the drug’s formula.

That composition-of-matter patent expires this month.

In spite of the last-ditch appeal, Lilly officials wrote late last month in a securities filing that they expect generic Gemzar to hit the U.S. market as early as mid-November.

Indian generic-drug maker Sun Pharmaceutical Industries Ltd.Teva Pharmaceutical Industries Ltd., Hospira Inc. and Novartis AG’s Sandoz are seeking to sell lower-cost versions of the medicine.

 “We are currently considering our remaining legal options,” Mark Taylor, a Lilly spokesman, said in an e-mailed statement. “We will not speculate on whether generic competitors will be prepared to enter the market upon expiration of Gemzar’s compound patent in mid-November.”

Lilly had asked that the original three-judge panel reconsider the case or that it be heard before all active judges of the court, which specializes in U.S. patent law.

Of the nine active judges, four said the case should have been heard before the entire court, saying there are questions about the legal standard to determine if there has been double patenting.

Gemzar is the first of several blockbuster Lilly drugs that will see their patents expire between now and 2013. Generic versions of Zyprexa, Cymbalta, Evista and Strattera could zap nearly half of Lilly's current sales, putting great pressure on the company to find new drugs to take their place.