Paul Smyth's exquisite volley had given Orient a 1-0 lead at the break following a dominant opening half from the league leaders.
But a triple substitution at the break brought about a much-improved second half display from Rovers and they hauled themselves level when Max Woltman’s pass found the run of Kyle Knoyle, who in turn crossed for Biggins to head home his first goal for the club.
Orient went closest to finding a winning goal but Omar Beckles headed onto the roof of the net.
Here’s our player ratings...
1. Match action
Doncaster's Harrison Biggins celebrates his goal with Ben Close. Photo: HOWARD ROE, Howard Roe/AHPIX LTD
2. Jonathan Mitchell - 7
Made a couple of decent saves before the goal, which he could do nothing about. Tipped a Moncur volley over the bar after the break. Still shaky in possession. Photo: Tony Johnson
3. Kyle Knoyle - 6
Should have turned in a chance from close range in the second half and looked below par until he found Biggins to assist the equaliser. Improved after that point. Photo: HOWARD ROE
4. James Maxwell - 5
Struggling for form and hooked at the break again, which won't be good for his confidence. Photo: HOWARD ROE