Keytruda is step closer to being funded is being labelled a win for those currently using the Melanoma drug.

LISTEN ABOVE: Melanoma New Zealand CEO Linda Flay speaks with Rachel Smalley

A provisional agreement between the company that makes Keytruda, MSD, and the government's drug funding agency, Pharmac, has been negotiated.

If signed off by Pharmac's board, the fully funded drug will be available by the start of September.

CEO of Melanoma New Zealand Linda Flay said it's an enormous step forward and will save lives.

"The biggest gain for patients currently on Keytruda - those people will be able to maintain their current regime without the stress of switching to an alternative treatment."

However, she said while the negotiation process has been going on, people have suffered.

"There's been a lot going on behind the scenes, a lot of campaigning, a lot of advocating for an effective drug."