(Reuters) - A federal appeals court on Monday rejected an effort by the comedian Bill Cosby to reseal court documents that helped support a ream of recent sexual assault cases against him.

The 3rd U.S. Circuit Court of Appeals in Philadelphia ruled that Cosby's appeal was moot after the contents, including "damaging" admissions he had made in a 2005 deposition regarding his sexual behavior, received wide publicity.

"Resealing the documents would not provide Cosby with any meaningful relief, and thus this appeal is moot," the court said. "The contents of the documents are a matter of public knowledge, and we cannot pretend that we could change that fact by ordering them resealed."

Cosby, 78, once one of the most beloved U.S. entertainers thanks to his family-friendly persona, has been accused by more than 50 women of sexually assaulted them, often after plying them with drugs and alcohol, in attacks dating back decades. He has denied having non-consensual sex with any of them.

The documents include comments Cosby made in a deposition about his sexual behavior in connection with a complaint filed in U.S. District Court by Andrea Constand.

Constand, a former basketball coach at Cosby's alma mater Temple University, accused the comic of offering her an unidentified pill that left her unable to speak or move, and then assaulting her on a couch at his Pennsylvania home in 2004.

Cosby has admitted giving Constand the allergy medication Benadryl but maintained they engaged in consensual acts.

The documents include admissions by Cosby that he had extramarital affairs, and that he had acquired the sedative known as Quaaludes and engaged in sexual relations with a woman after she took the drug, according to the appeal court's ruling.

They were unsealed by the U.S. District Court for the Eastern District of Pennsylvania in July 2015, and Cosby's lawyers later sought to have them resealed.

But the appeals court said the issue was moot because news organizations had published articles about the documents within hours of them being released, "and the news media have repeated his damaging admissions countless times since then."

Most of the allegations against Cosby are too old to be the subject of criminal prosecution, but the comedian faces a series of defamation lawsuits by women who claim he smeared their names when he accused them of lying.

(Reporting by Jonathan Stempel and Daniel Wallis in New York; Editing by Jeffrey Benkoe and Bernadette Baum)