"On January 7th at 9.52pm just a few hours after lots of kisses and cuddles from Sage and with me and his mum and brother holding his beautiful, strong hands, Kurt slipped away.
"I can't even begin to describe the depths of this ocean of pain and sadness I'm trying to stay afloat in. Christ I am so proud of the courageous battle he fought."
The 41-year-old had been receiving the potentially life-saving CAR-T treatment as part of a clinical trial in Boston, United States, since September.
He became aware of the trial by fellow Auckland man David Downs, 47, for which the treatment had been so successful Downs was now in remission, after being given a year to live.
The therapy takes the immune cells - known as the T cells - out of his body and genetically engineered them into "killer cells" before inserting them back into the blood.
Downs became good friends with Brunton and Janelle after Brunton got in touch about getting on the trial.
David Downs in hospital in Boston, America, in March last year. He became good friends with Kurt Brunton and is now in remission after taking part in the clinical trial. Photo / File
Downs, who has had to continue visiting Boston to have blood tests so medical staff can monitor his progress, visited Brunton in hospital while he was there.
Brunton-Rennie then got in touch when they landed back in New Zealand on New Year's Eve.
"She let me know a week or so ago that they had come back from Boston and I spoke to her a couple of days ago as well, so yeah. She's been quite incredible and she's had a really tough time."
Downs said Brunton had fought such a heroic battle he thought his mate would pull through.
"It's a really sad time. After such a big battle I really thought he would make it because he had put all the effort in. He was an amazing guy with such strength and determination.
"The support people around him, his wife and his mother, has just been incredible to watch and witness and they will just be distraught having gone through all the battle they've been through and now having this result, it's just heartbreaking."
Downs said he helped Brunton get onto the trial but not as quickly as he was able to.
"We managed to get him up there and I visited him in Boston a couple of months ago when I was there and saw him and hung out a little bit.
"The poor guy has just had so many difficulties in terms of the side effects and he had a lot of tumour burden, in other words, he had lots and lots of tumours."
Kurt Brunton with his wife Janelle Brunton-Rennie and their daughter Sage. Kurt lost his battle with cancer two days ago. Photo / Dean Purcell
Ironically, the side effects Brunton was suffering were due to the treatment working.
"The way the treatment works is that you're re-training your immune system to fight cancer. If you've already got a lot of cancer then your immune system just goes nuts and the side effects of that is there's incredible fevers. He had neuro toxicity so it made him semi-conscious for a few days.
"But that was actually the side effect of it working. It was working so well and so fast that it was causing shock to the system."
However, while the first round of therapy got rid of most of the cancer, what was leftover was growing so fast his immune system couldn't keep up the fight.
"They gave him some drugs to keep it going and accelerate it but the cancer was just so fast growing and he was pretty weakened by it after a couple of years of fighting it."
He said he was dedicating a lot of his time to getting the therapy in New Zealand. He'd been working with the Malaghan Institute in Wellington which was currently doing all the paper work and permits to have it in the country within the next few months.
But while the institute was doing its work, it still needed to raise the money to have it on offer.
It would initially be for treatment of blood cancers, like Downs and Brunton suffered, lymphoma, leukaemia, but it would eventually branch out into other diseases too.
Downs said while money was a massive barrier to must cancer sufferers, being away from family and support networks was also huge.
"Kurt and I talked about it a lot. Like me, he saw having to go the other side of the world, first of all there's a financial cost but for many people it's just mentally a huge step to have to go to another part of the world and Kurt was away from his wife and child for months. He was over there with his mother because the baby's so little she couldn't travel."
Downs said his survival was likely due to a combination of getting on the trial a bit earlier than Brunton and his cancer not being as aggressive.
"By the time Kurt got to getting on the programme it was already pretty far advanced. Whereas mine was terminal, I was told I had a year to live which is pretty confronting, but I got on it really fast and I think mine was slower growing. I had side effects but not nearly as bad as Kurt."
* Those who can help get the CAR-T therapy to New Zealand or want more information about how it works can head to downwithcancer.nz.
