NEW YORK • American comedian Bill Cosby, who is serving a three-to 10-year prison term, has filed a new appeal against his conviction for drugging and sexually assaulting a woman 15 years ago.

In court documents filed on Tuesday with Pennsylvania's Supreme Court, Cosby's lawyers argue that five women should not have been allowed to give evidence at his trial as witnesses. They say their "decades-old" allegations, which were not part of the charges, had prejudiced the jury.

The lawyers also argue it was "fundamentally unfair" the deposition testimony Cosby, 83, gave in a civil case regarding his use of sedative drugs and his sexual behaviours in the 1970s was heard in court.

They say Cosby believed the testimony was immune from prosecution when he gave it.

The actor fell from grace as allegations of sexual misconduct emerged against him. He was found guilty in 2018 of assaulting former university administrator Andrea Constand, 47, at his Philadelphia mansion.

It was the first celebrity trial and first guilty verdict for sexual assault since the advent of the #MeToo movement.

A Pennsylvania judge sentenced the actor to a minimum of 31/2 years in prison on three counts of aggravated indecent assault.

Although more than 60 women say they had been victims of sexual assault by Cosby, he was tried criminally only for Ms Constand's assault, since the statute of limitations had expired in the other cases.

A dozen women who say they were victims of Cosby have filed civil suits against the actor seeking compensation for damages.

AGENCE FRANCE-PRESSE