Australian researchers believe they have made an important step toward curing melanoma after its spread from the skin to the lymph nodes.

Scientists have shown they can stop melanoma from spreading to distant organs - a breakthrough that has the potential to significantly reduce the number of Australians dying from the skin cancer, experts say.

Two international drug trials - led by investigators at Melanoma Institute Australia (MIA) - have proven successful in preventing the spread of the disease in Stage III melanoma patients whose tumours had been surgically removed.

"These clinical trials show we now have ammunition to prevent melanoma spreading and progressing, which until now was a critical area of disease behaviour where we had no control," Professor Georgina Long, the institute's conjoint medical director, said.

"Our ultimate goal of making melanoma a chronic rather than a terminal illness is now so much closer to being achieved," Prof Long said.

In Australia, one person dies of Melanoma every five hours.

If identified early, melanoma is easily cured via surgical removal from the skin surface. However for about 15 per cent of melanoma patients the disease has spread to the lymph nodes which is classified as Stage III melanoma.

Until now, these patients were at a high risk - 40 to 70 per cent - of their disease progressing to advanced and fatal melanoma.

Prof Long says the trial results will change the way melanoma patients are treated as well as their quality of life.

"Stage III melanoma patients who have had their tumours surgically removed have simply had to play the waiting game, to see if their melanoma would metastasise or spread. Living with such fear severely affected them and their loved ones," Prof Long said.

For the first clinical trial - called COMBI-AD - patients were randomised to receive a combination of targeted therapies (dabrafenib and trametinib) or placebo for 12 months.

The drugs work to block the action of a particular gene mutation - known as BRAF - that drives the spread of the disease. This mutation is present in about 40 per cent of melanoma patients.

"This trial showed a 53 per cent reduction in the risk of the melanoma coming back," Professor Richard Scolyer, co-medical director at MIA, said.

The other trial called CheckMate 238 compared two immunotherapy drugs - novlumab versus ipilmumab - on patients with high risk Stage III and Stage IV disease.

"The novlumab caused a reduction in the risk of recurrence of melanoma by 35 per cent, that can work in all melanoma patients not just the ones with the BRAF mutations," said Prof Scolyer.

Published in the New England Journal of Medicine, the results were presented at the European Society for Medical Oncology (ESMO) 2017 Congress in Spain on Monday.

Currently, these drugs are only approved for patients with Stage IV melanoma, however it's hoped the new research will build on a case to make these drugs available to those with earlier stages of the disease.

"Previously there was no therapy for these patients to mop up the tumour cells and these new drug therapies are able to do that, so basically in effect stopping the disease in its tracks," said Prof Scolyer.