Four fire engines and around 20 firefighters dealt with a house converted into flats fire on Bruce Road in Bromley by Bow.
Half of the second floor was damaged by the blaze.
Station Commander Richard Wyatt said:
"Crews worked exceptionally hard in hot conditions to bring the fire under control. Two women left the property before the Brigade arrived."
The Brigade was called at 1014. Fire crews from Poplar, Stratford, Bethnal Green and Millwall fire stations are at the scene. The cause of the fire is not known at this stage.