BOCA RATON, Fla. — A Florida woman who came forward Thursday became the fourth in recent weeks to say Bill Cosby gave her pills that made he feel groggy then forced himself on her sexually.

Therese Serignese, now 57 and a nurse in Boca Raton, said the television icon raped her in 1976 when she was 19 years old following a show in Las Vegas. She said she went backstage and when the two were alone, Cosby gave her two pills and a glass of water, saying, “Take these.”

“My next memory is clearly feeling drugged, being without my clothes, standing up,” she said. “Bill Cosby was behind me, having sex with me.”

Dozens of Cosby’s television and comedy colleagues have either refused to comment or not returned telephone calls from the AP in recent days.

The allegations by Serignese and three others are similar:

• Barbara Bowman, an aspiring actress, said in a Nov. 13 Washington Post column that she was 17 and blacked out after Cosby drugged her, waking up to find herself in panties and a man’s T-shirt with the television icon looming over her. She said she was certain she was raped.

• Joan Tarshis on Monday said she was 19-year-old who wanted to be a comedy writer when Cosby gave her a drink and forced her to perform oral sex on him.

• Janice Dickinson on Tuesday told “Entertainment Tonight” that Cosby had given her red wine and a pill when they were together in a Lake Tahoe, California, hotel room in 1982. Cosby’s lawyer, Martin Singer, said in a letter to the AP that Dickinson’s charges were “false and outlandish.”

Serignese says after the alleged rape, she willingly stayed with Cosby in Las Vegas for some time, but could not specify how long or whether the two had sex again. The two also maintained sporadic contact.

Cosby spokesman David Brokaw did not respond to a request for comment. Cosby’s lawyer, in a statement released Sunday, criticized previous “decade-old, discredited allegations,” stating that “the fact that they are being repeated does not make them true.”

The 77-year-old television star’s attempt at a career comeback has been collapsing in recent days as the abuse allegations resurfaced. This week Netflix said it was postponing a comedy special it had planned with Cosby to air later this month; NBC said it was stopping development of a sitcom with him.