The Bosnia Herzegovina international has scored two goals in 12 league appearances to help Roma lead the Serie A standings.
The 23-year-old midfielder is a reported target of Manchester United, Manchester City and Tottenham as well as Russian side Zenit.
"I still have a year and a half left in my contract," Pjanic said in comments reported in Corriere dello Sport.
"Until 2015, I will probably remain at Roma. I don't know what will happen after that but we are discussing it.
"My intention is to remain here for a long time because I am happy. I don't exclude the possibility of one day playing elsewhere, but I doubt this will happen soon."
Pjanic joined Roma from French side Lyon in the summer of 2011 and has been a regular in Rudi Garcia's squad this season.