Known as MK-3475, the drug reportedly cured Walker's cancer when he was undergoing a life-saving PD-1 treatment in the United States back in 2013.
The drug has been found to generate a positive response in 50 percent of patients suffering from advanced melanoma and is better than the current most effective treatment, Yervoy, which was found to be beneficial for 10 to 20 percent of the patients.
"It worked a miracle. In fact the professor said to me: 'Do I believe in miracles?' and I said: 'yes I do'. I'm a living example of a drug that actually works because the cancer is gone", Walker told 7News health reporter Karen O'Sullivan.