Comedian Bill Cosby has lost a bid to keep Pennsylvania prosecutors from using his own words against him at his criminal sexual assault trial, currently scheduled to begin no later than June.

Judge Steven O'Neill of the Court of Common Pleas in Montgomery County, Pennsylvania, ruled on Monday that prosecutors can introduce potentially damaging sworn testimony the 79-year-old entertainer gave about his sexual history during a civil case in 2005.

The testimony, in which Cosby acknowledged giving young women Quaaludes before engaging in what he described as consensual sexual acts with them, helped persuade the Montgomery County district attorney to file charges after it was unsealed in 2015 by a federal judge.

Cosby, the star of the 1980s television hit "The Cosby Show," has seen his once family-friendly reputation buried under a blizzard of sexual assault accusations from around 50 women going back decades. The Pennsylvania case is the only criminal prosecution he faces, though he has been hit with multiple civil lawsuits.

Andrea Constand, a former basketball coach at Cosby's alma mater of Temple University, first accused Cosby in 2005 of giving her unspecified pills and then assaulting her at his home a year earlier.

Cosby's lawyers had argued that the district attorney at the time, Bruce Castor, had promised Cosby he would not prosecute if Cosby agreed to testify under oath in Constand's civil lawsuit.

The deal was intended to give Constand some measure of justice, since a criminal case could not be supported by the evidence, according to Castor, who testified at a hearing this year.

But O'Neill ruled that Castor's account was inconsistent and said no written evidence of a non-prosecution deal exists.

"Because there was no promise, there can be no reliance on the part of the Defendant and principles of fundamental fairness and due process have not been violated," he wrote.

A spokesman for Cosby declined to comment.

O'Neill has scheduled a two-day hearing next week to address various pending pretrial matters, including a request from prosecutors to call as trial witnesses more than a dozen other women who have leveled assault accusations against Cosby.