Brandt's four league goals have contributed to a fine season for Leverkusen, who are second in the Bundesliga table after 20 matches, albeit 16 points behind champions Bayern.
Germany international Brandt told Omnisport in October it was an "honour" to be linked with Barcelona, while Bayern hold a long-term interest in the 21-year-old.
But with Leverkusen on track to return to the Champions League after finishing in the bottom half of the Bundesliga last season, Brandt could remain at the BayArena.
"It's all possible," Brandt told Kicker of a possible new contract.
"The fact is that I feel comfortable here, I really enjoy playing in this team, but in the future, nothing has yet been decided.
"No question, we are on a great path. What the coach [Heiko Herrlich] says, how we play, the squad: it's all there and that's a great foundation."