One of the men who suffered severe reactions to an experimental drug during a drug trial in London, UK, says he now has cancer.
The trial of TGN 1412, designed to treat chronic inflammatory conditions and leukaemia, was conducted on behalf of German firm TeGenero by contract research firm Parexel.
New Zealand born David Oakley who suffered organ failure and pronounced swelling, was one of six men who became seriously ill following trials of the drug and now has the early signs of cancer.
He is seeking compensation from Parexel, the company which arranged for the drug trials to take place.
The six volunteers took part in the trials in London's Northwick Park Hospital in north-west London in March this year for which they were paid £2,000.
A volunteer who was given a placebo has described how the other men were writhing in agony, vomiting and screaming over the pain in their heads shortly after taking the drug.
Mr Oakley, a driving instructor from Ealing, west London, took part in the trial to raise money for his wedding in June to wife Katrina, 29.
He has been told by doctors that he has "definite early signs" of lymph cancer and has also been warned that he faces the risk of multiple sclerosis, lupus, ME, rheumatoid arthritis and other illnesses.
There is however no evidence to show Mr Oakley's cancer which was discovered two months ago, was caused by the experimental treatments.
Oakley, 35, said his life has been on hold since and he believes Parexel should be accountable and hopes the company will "do the right thing" in respect of his claim.
Parexel is a clinical research organisation which carried out the trial on behalf of TeGenero, a German pharmaceutical company, and the Medicines and Healthcare products Regulatory Authority (MHRA) has said Parexel failed to follow proper procedures.
The watchdog found there was no contract in place between TeGenero and Parexel at the beginning of the trial, but TeGenero has maintained that the men's reactions were "completely unexpected" and did not reflect the results obtained from the earlier laboratory studies.
Parexel has previously said all guidelines were followed during the drug trials.