It was a last-ditch attempt. And Trevarthen and her partner Greg Robertson now describe the drug as their miracle.
The first treatment saw two tumours jutting out of Trevarthen's painfully thin back start shrinking. One has now disappeared, and scans show tumour activity is declining.
Trevarthen and Robertson can see light at the end of a dark cancer tunnel and more Keytruda is booked.
Robertson has a message for the mesothelioma cancer that almost stole the love of his life. He also has a message for the Government as it debates funding Keytruda. Here are his words.
Dear Mesothelioma,
You're a p****. For six months you've owned us. You've smashed us as one bad piece of medical diagnosis was delivered after the other. You showed yourself to Dee and me as you bulged in two massive lumps on her back - the size of a lemon and orange - seemingly desperate and delighted to push out of her skin.
But that was just a taste of you. The biopsy had dragged your bastard cells to the surface and you grew in the limelight like you were on a super steroid. You laughed in our faces, knowing that it was just indeed a taste of you. Inside was where all your dirty work was being done. You shrunk her to 35kg.
Dee's painful screams were a testament to that filthy toil inside her.
You had us both. You flattened us. Dee desperate on a bed in Hospice and me exhausted and with near lost hope. Wonderful Hospice staff tending to us both.
Through it all you've had your messengers. Lots of words. Powerful, painful words: "Terminal... no chance... get your affairs in order... metastatic...three to five weeks... you need a miracle... do not resuscitate".
Well I have a message for you Mr Malignant Pleural Mesothelioma. We're not done yet.
It's our bloody turn. How does it feel? How does that Keytruda feel, mate? You're not looking the best. We saw your pain 10 minutes after it first went in. It scared you, didn't it.
The first taste of a medicine that would be a "miracle" if it worked? We could tell though... Dee felt you, oh she felt your pain. When we pulled off the motorway and injected her with strong painkillers it wasn't for your benefit. It wasn't to ease your pain.
The game had changed, and when a power shifts there's often pain. Beautiful people like my mum and Brenda sat in the back, four hands squeezed together in terror as they could only watch Dee arch in agony. But this was different. This pain came from a deep place where the cancer had once been and gone and had marched on in all glorious super aggression. This time though, Dee felt your pain.
Today, one of those lumps... the bigger one, well it's gone. The other is a shadow of its former self.
Well, mate, that was just the beginning. Today, as a sporting heads up, we scheduled three more rounds of that. Enjoy. She's coming after the rest of you.
Today, we saw the CT scan results that showed we have you on the run. Today we started to truly believe in the word miracle.
My message for the New Zealand Government and the ACC Minister is clear. It's time to fund Keytruda. Not only for melamona. It's time to fund it for all cancers.
If you fund Keytruda for only melanoma you are sentencing others to a needless death. Asbestos cancer is the worst type of cancer with the worst types of tumors. Dee had the worst of the worst. And Keytruda still worked.
Man made asbestos cancer. Businesses have profited from the asbestos product it came from. But Deanna is having to pay in every single way. Paying $10,000 every three weeks for Keytruda is not fair. We don't have that sort of money. She shouldn't have to pay to save her life.
To friends, family and supporters we still have a long, long way to go but this is truly wonderful news. Right here, right now - we're on top.
To date, Deanna Trevarthen and Greg Robertson have spent $45,000 on treatments. They have three more rounds of Keytruda booked.
To help, visit givealittle.co.nz/cause/deesday/
Keytruda facts
• Keytruda is the brand name of the immunotherapy drug, pembrolizumab.
• It is administered by infusion in hospital and is designed to allow a person's own immune system to destroy cancers.
• Drug-maker Merck Sharp and Dohme has applied to Pharmac for funding of Keytruda in New Zealand for advanced melanoma that cannot be treated by surgery.
• It costs $10,000 every three months
• It is funded in the United Kingdom, Australia and the United States for advanced melanoma. It is also licensed in the US for lung cancer treatment.
• In February a 54,000 strong petition was presented to Parliament calling on the New Zealand Government to fund Keytruda. The petition was started by Leisa Renwick, who was treated with Keytruda and another drug, Dabrafenib, and survived stage-four melanoma after she was given a few weeks to live.
• Pharmac has given funding Keytruda a low priority, stating they are waiting for results of further studies of the drug's effectiveness.
