A 16-year-old boy was treated for minor injuries and arrested on suspicion of conspiracy to commit GBH. Another man remains in custody on suspicion of attempted murder.
The Mile End attack was one of four stabbings across the capital on Thursday night, which left six people in hospital and five in police custody.
The first involved a teenage boy knifed in East India Dock Road, Westferry at 5.30pm, followed by the Grove Road attack and another teenager stabbed outside a HSBC bank in Ealing Broadway at 7.05pm.
Just minutes before a 13-year-old was left with knife wounds in Gainsborough Avenue, Manor Park, east London at 6.57pm.
London has been devastated by a wave of bloodshed in recent weeks, with police and politicians on edge after the city's crime rate surpassed New York's.
Commenting on the Mile End incident, a Met Police spokesman said: "Two boys, aged 15, taken to hospital following stabbing in Grove Road, E3 remain in hospital in a serious but stable condition.
"The 16-year-old treated for minor injuries has now been arrested for conspiracy to commit GBH. Another male also remains in custody for attempted murder."
Witness Jack Hawke, 33, who lives further down the street, described the horrific attack.
He said he heard "yelling" and went to his window, where he saw three boys, one on a bicycle, with their faces covered.
Another, Jack Hobbs, 30, walked past what appeared to be the same group on Grove Road and said: "They were all wearing dark clothes with their hoodies sort of fastened up at the top so their heads were completely covered."
