Navneet Modi and Mohamed Abdelhady criticised the companies behind the tests, saying they were not given adequate warnings of side effects and that the trial should have been abandoned as soon as the horrific reactions began.
They were among six volunteers left fighting for their lives as their immune systems collapsed and their bodies swelled when they were injected with the experimental drug TGN1412 three weeks ago.
In an interview to be screened tomorrow night, Mr Modi, 24, said: "I am broken physically. I have difficulty in walking. Whenever I think about it I shatter into tears. I can't control it."
Mr Modi, who was aiming to use his £2,000 fee to buy a new laptop after completing an MBA, told ITV1's Tonight with Trevor McDonald: "Whenever I think about it I feel a bit depressed and I feel as if life has got no meaning for me now."
He claimed he was told only of minimal problems that might occur from the drug. "The risk they mentioned was some headache and nausea. They didn't mention any other risk apart from that."
Mr Abdelhady, 28, who was left in a coma for more than a week, said he has been told his immune system may never recover. Recalling his time in the ward at Northwick Park Hospital in Harrow as the trial took place, he said he became increasingly worried as he saw another of the human guinea pigs complain of severe headaches and sickness.
"There was a guy from New Zealand who was injected 10 minutes before me and I remember him saying he didn't feel well, that he had a bad headache, like rockets going off in his brains," he said in a newspaper interview. "When people started feeling ill they should have called off the test.
"I started to feel ill almost as soon as they had finished injecting me. I felt as if I had rocks on my head and I must have started hallucinating."
The Egyptian-born bar manager, who was also to be paid £2,000 for the trial, collapsed as he tried to make his way to the toilet.
"The last thing I remember was my body turning lifeless and crumbling to the floor," he said. He was unconscious for eight days as his body swelled. He had to breath and be fed through tubes and was given steroids for five days to allow his organs to recover.
Mr Abdelhady's head swelled to such an extent that his girlfriend Myfanwy Marshall, who kept vigil by his bedside throughout the ordeal, described him as looking like the Elephant Man. "His eyes were bulging out and his face had ballooned. There was no movement, nothing. He looked dead."
The swelling has subsided, but his skin is now peeling off in patches. He feels drained and even a short walk leaves him breathless. Mr Abdelhady will remain in hospital for another fortnight.
In a joint interview, which he and Ms Marshall gave to the Daily Mirror and Daily Mail, Mr Abdelhady said he believed the drugs companies should have done more investigation before conducting the first human trials of the drug, developed by German company TeGenero and administered by medical research company Parexel.
"I'm very happy-go-lucky, but this whole awful experience has fundamentally changed me. It seemed like a straightforward thing, but that injection changed me for ever," he said.