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Toni Ann Filiti, the 48-year-old half-sister of Sylvester Stallone, died Sunday of lung cancer at her mother's home in Santa Monica, Calif. Her death comes six weeks after Stallone's 36-year-old son Sage died of a suspected drug overdose.

"What a terrible month," Stallone's 90-year-old mother, Jackie, told the New York Daily News. "First Sage and now Toni. It's hard. At least they're together now in heaven."

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Jackie Stallone said she broke the news to her famous son after her daughter died in her arms. "He said he can't take any more pain," she told the paper. "He said he'll always be there for her son."

Toxicology results are still pending for Sage Stallone, following his death on July 13.