Cyclist safety is one of the mayor's highest priorities, the Boris Johnson's cycling commissioner said.
Andrew Gilligan said:
Our thoughts are with the family and friends of the cyclist who died today.
We are spending almost £1 billion to make London's roads safer for cyclists. We are designing segregated cycleways, rebuilding the most dangerous junctions, and talking to the Government about fitting all lorries with safety equipment.
This work cannot be done instantly - indeed, it would be counterproductive to do so. But it is being done quickly. It is one of the mayor's highest priorities.
More top news
The 20-year-old was found fatally wounded on Roth Walk, near Finsbury Park, north London at around 3am on Saturday, Scotland Yard said.
Police have arrested a man wanted in connection with a burglary at the home of pensioner Richard Osborn-Brooks.
The rally comes after it emerged that the Home Office destroyed thousands of landing cards documenting the arrival of windrush-era migrants