At that time there was no funded effective treatment for advanced melanoma.
A little over a year later and Pharmac now funds two - Opdivo and its rival Keytruda - a change in large part down to the campaigning of Renwick and other melanoma patients.
The maths teacher at Mt Maunganui College handed over the petition on Parliament's forecourt in March and - surrounded by television cameras - spoke to Health Minister Dr Jonathan Coleman.
Pharmac had cited a lack of evidence about Keytruda's efficacy and said evidence presented by maker Merck Sharp & Dohme had not been peer-reviewed.
But after a $39 million boost for Pharmac was confirmed in May the drug-buying agency proposed to fund rival melanoma drug Opdivo.
And last month it confirmed it would also fund Keytruda - also known as pembrolizumab.
That reversal put Renwick in the unusual position of this morning appearing before Parliament's health committee to present on a petition that had already been successful.
Her triumph was tempered by the fact that a number of melanoma patients known to Renwick had died in recent days.
"For some reason this has been a particularly bad week. It is the people who have hung on and hung on and have got that first treatment, but it has just come too late for them.
"And it is wrong that it was actually seen to be acceptable. But that was the way it felt - it was acceptable to lose a certain number of people."
Renwick, flanked by fellow melanoma patients Kathryn Williams from Wellington and Sarah Speight of Tauranga, told MPs on the health committee that reform of Pharmac was needed.
Assessments of new drugs needed to separate cost considerations and efficacy, she said.
The turn-around on Keytruda funding was always about money and not new evidence, she said.
"I would have had a lot more respect for the people of Pharmac if they had stood up and said, 'Hey, this drug looks very promising... but it is very expensive and we don't have room for this in our budget'. If they had done that, then we could have worked with that.
"Quite frankly, them standing up and confusing the two issues - it was offensive."
Renwick also wants more transparency in the drug funding process and a full appeals process for decisions to be challenged.
During the debate on Keytruda some had criticised it as becoming politicised, she said, but there was little other option to have patients' voices heard.
More flexibility was also needed to allow access to promising treatments, Renwick said, with one promising model used in Italy linking payments to drug companies to results.
"Unless we make positive changes to our pharmaceutical purchasing model so that it steps into the 21st century with us, as a country we are going to be left behind and you can expect many more petitioners to arrive on the doorstep of Parliament house," she told the committee.
Renwick, who had no sign of melanoma in June after courses of a gene therapy drug and Keytruda, afterwards told media that she viewed today's presentation as a last duty before a break.
"I think it has been harder for my family in some ways. At the time I was really ill I wasn't really thinking very coherently - I was taking a lot of drugs - and I was dying. My oncologist told me the other day that I was circling the drain.
"So it was really hard for my family... and I think I owe them some time now."
