"I debated him for four and a half hours," she said, recalling their acrimonious exchanges. "I don't even think about responding to him anymore."
She was speaking to reporters aboard her campaign plane.
Mr Trump used a rally in Gettysburg to promise curbs on lobbying and new trade and climate change negotiations.
With just 16 days until the election, much of the recent focus has been on controversies linked to his campaign.
On Saturday, he again promised to sue every woman who had accused him of sexual assault or inappropriate behaviour as soon as his presidential campaign was over.
While the tycoon lags behind Mrs Clinton in opinion polls, he recently narrowed the gap to about four percentage points.
Clinton urges unity
Asked about Mr Trump's threat to sue his accusers, Mrs Clinton said her focus had turned to helping elect other Democrats on 8 November, when Congressional seats are also being contested
"He can say whatever he wants. He can run his campaign however he wants to," she said.
"I'm going to let the American people decide between what he offers and what we offer."