A three-judge panel of the 11th Circuit Court of Appeals ruled Tuesday that the U.S. District Court for the Middle District of Florida had correctly dismissed the case brought by Linda Guinn, a former legal secretary from Palm Bay, Fla., in her early 60s.

Before that case was to go to trial, AstraZeneca successfully argued in January 2009, before District Judge Anne Conway, that Guinn's doctor did not qualify as an expert under federal court rules and so her testimony should be excluded. The drugmaker also persuaded the judge to grant a summary judgment motion in its favor, arguing that Guinn failed to establish that Seroquel caused her diabetes.

The 11th Circuit Court, based in Atlanta, upheld those decisions.

"The appeals court decision echoes earlier federal and state court opinions that found Seroquel could not be proven to be responsible for plaintiffs' alleged injuries," AstraZeneca spokesman Tony Jewell said in a statement.