If the defense gets really aggressive, playing press outside and committing extra players to the run, they can scrape exchange with the DE and LB, and then cover the quick stuff (well, as good as anyone can cover Dontre in space this year...good luck with that, defenses).
Basically, the defense always has two "extra" players vs. a traditional run play; the counterparts to the running back and the quarterback (who hands the ball off but is not a threat). To stop the option purely from a numeric standpoint, you have to deploy both of those defenders to the run. Packaging a quick passing play with the QB option doesn't really change the arithmetic.
What it does do is put added stress on the defense, and it controls where those "extra" people can come from. You can't cheat a player in to stop the run from over the slot receiver (e.g. a nickel back), for example, because now that receiver is a threat. So to really gear up to stop the run, you have to play Cover-0 or quarters, aggressively turning your safeties loose against the run. To try to stop the quick passing game, you might play press or you might play off coverage and squat on routes, anticipating short breaks and trying to jump them as the QB delivers the ball.
If the defense turns to such an aggressive scheme, it could force a keep read by the QB, send someone to tackle him, and cover the quick routes. If you execute, that's a sack/TFL and the defense has put the offense in a situation where the run or packaged pass is less likely. However, if the offense makes one guy miss, there's no one deep to cover up the mistakes. If the defense plays aggressively anticipating run, but it is actually pass, there are a lot of one on one matchups which should/could be big gains for the offense.