Ryan announced he would leave the race after allegations became public in June that he tried to pressure his then-wife, television actress Jeri Ryan, to perform sex in front of strangers at sex clubs in Paris, New York and New Orleans.
Ryan has not yet filed papers with the state Board of Elections to withdraw his candidacy. As winner of the March Republican primary the GOP can't force him off the ballot.
The party has not found a replacement candidate.
A newspaper columnist urged Ryan to stay in the race, but Topinka had different a message.
"Do it. Enough harm has been caused the party. It's time to move on," she said in an interview with Crain's Chicago Business. She said all Ryan has to do is fill out a one-page form.