Four fire engines and around 25 firefighters were called to a house fire on Grange Road in Plaistow.
Most of the ground floor of a terraced house and part of the roof were damaged by fire. The first floor of the building was destroyed by the blaze. Two men were out of the building before the Brigade arrived and were taken to hospital. Firefighters led another man to safety who was also taken to hospital.
The Brigade was called at 0527 and the fire was under control by 0745. Fire crews from Plaistow, Stratford, Poplar and East Ham fire stations attended the scene.
The cause of the fire is under investigation.