DANIEL Roper had just two days to live, his body riddled with cancer. Then he took a new experimental drug.

And overnight on February 28, he miraculously recovered.

Four days later, he walked out of a Melbourne hospital looking forward to continuing his life.

The extraordinary 11th-hour joint bid by a US drug company, hospital ethical boards and his doctors gave Daniel a long shot at a drug trial that was not even supposed to be up and running.

"I felt like I was going to burst," he said.

"It was literally overnight that the fluid started draining and all the signs started moving in the right direction. The speed of it was just amazing."

The 25-year-old, from Northcote in Melbourne's north-eastern suburbs, only learned that melanoma had spread through his body in December and by January his spine, liver, lungs and ribs were riddled with tumours.

His only hope was a transfer to the Austin Hospital, in Heidelberg, where an experimental drug combination targeting cancer's on/off switch BRAF and its driver MEK simultaneously was due to be trialled later this year.

Only 60 people in the world are being selected for the trial, a world first.

But as he waited, Daniel suddenly deteriorated and blew up with a massive infection in his abdomen.

Rushed to hospital, he had 19 litres of fluid drained from his body in two days.

As he slipped away, calls were made across the globe to bring the Victorian part of the trial forward.

Daniel's situation was so dire his mother Helen could only hope he would hold on for a few days for his sister to arrive from the US.

"I could see him going in front of my eyes. I have been nursing for 30 years and I knew he wasn't going to last," an emotional Ms Roper said.

"When he started on that drug he was told it would either work in the first couple of days or not at all.

"But to see the change by the Wednesday when his sister arrived - he was already a lot better."

The drug trial is very much in its infancy. How successful it will be is unknown, and so is Daniel's long-term prognosis.

But if his cancer learns to resist the drug he takes daily and does return, Daniel hopes other advances will overcome it again.