Russell Slade's men show no signs of falling away and their unbeaten stretch this season now stands at 11 games after Saturday's 2-1 home win.
The in-form Patrick Bamford (30) put the Dons in front with his 11th of the campaign, but Moses Odubajo equalised before the break and Kevin Lisbie won it for Orient midway through the second half.
Peterborough remain their nearest challengers in second after a 1-0 win at Port Vale.
It was not as free-flowing as Peterborough often are, but the points were secured when Tyrone Barnett netted with five minutes left.
With third and fourth-placed Wolves and Bradford not in action, fifth and sixth-placed Preston and Rotherham had a chance to make a move up the ladder, but both suffered surprise home defeats.
Simon Grayson's North End were beaten 2-0 at home by out-of-form Crewe, with Byron Moore and Bradden Inman scoring the goals.
Rotherham's misery was even greater, shipping four without response at home to Swindon.
After starting well the Millers faded and Alex Pritchard opened the scoring for Swindon in the 31st minute, before Massimo Luongo added a deflected second before half-time.
The procession continued in the second half with Nicky Ajose making it three (65) and Dany N'Guessan wrapping things up late on.
At Colchester, an injury-time free-kick from Andy Taylor earned visiting Walsall a 1-1 draw.
Freddie Sears had put United ahead early on but Taylor ensured a share of the spoils for Dean Smith's men.
Francois Zoko scored his second and third goals in two games as Stevenage recovered from a goal down to beat Brentford 2-1.
Clayton Donaldson's fourth in five put the Bees ahead (13) but an error from David Button let Zoko level within seconds, with the striker putting the game to bed before the break.
In the day's other game, Joe Jacobson's header and Liam McAlinden's first career goal helped Shrewsbury see off Gillingham 2-0.