Four of the volunteers who were taken seriously ill during a drugs trial have been given unconditional interim payments of £10,000.
The men suffered multiple organ failure from the drug
Their lawyer said the money was given by insurers to help in the short term.
Six volunteers took part in the trial by medical research company Parexel at Northwick Park Hospital in Harrow, north-west London, in March.
They suffered multiple organ failure after being given TGN1412, produced by drug company TeGenero.
Lawyer for the men, Martyn Day, said: "I am very pleased that we have been able to reach a sensible agreement with the insurance company.
"This will enable our four clients to finance the coming few difficult months while we try to work out quite how bad is the cloud hanging over their heads following the drug trials."
The men had volunteered to test the medication, which was designed to treat rheumatoid arthritis, leukaemia and multiple sclerosis.
Earlier this month, the four volunteers rejected a payment of £5,000 from TeGenero.
Mr Day said the offer was on condition the men did not sue the company.
A lawyer representing the two other men - Ryan Wilson, 20 and Mohammed Abdelhady, 29 - declined to say whether her clients had been offered the same amount.
The payments were made after a meeting between TeGenero's solicitors, their insurers and the victims' solicitors.
Mr Day said that while the company had accepted responsibility for the insurance claim, it might not be able to meet it because it was a newcomer to drug trials.
Mr Wilson, a student from Highbury in north London, and the most seriously affected of the six, is likely to receive most of the legal damages.
He could be in hospital for six months and has been told his hands and feet may have to be amputated.