Asked how she affords it, she said she and her husband both have good jobs, she has tapped into some funds, and she has cashed in her superannuation.
Pharmac is in negotiation with several manufacturers of what have proved to be wonder-drugs for some melanoma patients and some which might have wider applications.
Keytruda was registered in New Zealand last September but Pharmac's clinical professionals have classed it a "low priority" until it gets better data on survivability.
Leisa Renwick is now well enough to have organized the petition, which will be received by her local MP, Simon Bridges.
"He is sympathetic but he emphasizes that he is receiving the petition as a Member of Parliament, not as a minister, that Health is not his portfolio and he cant intrude on the Minister of Health's portfolio."
She said was not happy that Health Minister Jonathan Coleman did not have the time to meet the petitioners "yet when you look at his Twitter feed, he seems to be taking his responsibilities as Minister of Sport very seriously."
Her message to Dr Coleman was one of responsibility: "They are accountable for this decision. They keep trying to say they are separate from Pharmac but Pharmac are owned by the Crown."
"The fact is he has people who are dying and will die if they are not treated. Some of them will die anyway. The medicine wont work for everyone but at the moment, they don't even have the chance to fight."
In the past there had been no treatment for melanoma but now there was.
Dr Coleman told the Herald last night his diary was "chokka" but he was already aware of them.
He said he had met a lot of people suffering from metastatic melanoma, which had spread throughout the body, and he had a huge degree of sympathy for them.
"They are facing a bloody terrible situation."
But his position was the same.
'You have got to leave this to Pharmac to make the decision at arm's length."
He acknowledged that National promising to fund extra treatment for Herceptin in 2008 and keeping at arm's length now looked like hypocrisy.
"But we have learned over seven years that you cannot just pluck individual drugs out of the air."
He would be trying to get more funding for Pharmac in the May Budget.
"If we get more money into the Pharmac budget, that allows to move down through the list of drugs on their funding priority list so it basically moves the threshold down until you get to a point where you fund Keytruda."