I don't think Borrussia Dortmund will be able to stop Bayer Leverkusen this season because Borrussia Dortmund will have to fight again to get into the top four of the Bundesliga standings. But for Bayern Munich, it is still quite possible for them to stop Bayer Leverkusen because considering that the distance between Bayern Munich's points is still quite close to Bayer Leverkusen in the standings, it does not rule out the possibility of making Xabi Alonso's team difficult again in the second half of this season.
The Bundesliga title race is on and Bayer Leverkusen have been leading from the early moments of the first season till current date. A difficult team is well known to be a complex club finding it hard to cooperate within themselves. The possibility of Leverkusen losing points currently is 10% because Xabi Alonso and his squad already know what to do inother to win matches, they're no longer relenting, rather they would lay targets on winning results. Borrusia Dortmund tried to stop Bayer Leverkusen by becoming the first team to hand them their first defeat of the season, luckily Leverkusen escaped with slim chances.
Let's just hope that Bayern Leverkusen keeps winning their games. One thing I know is that they won't end the season unbeaten, but even if they are going to lose games it shouldn't be now.