The Broseley four-year-old is home and in remission from the rare form of leukaemia after pioneering treatment in the US – paid for by a phenomenal fundraising effort from people across the country.
The youngster announced the news in a video where he also thanked everyone for raising the £500,000 to pay for his treatment, which was not available on the NHS.
It means his family can now get back to normal, with Zac able to start school, and look forward to his fifth birthday later this month.
WATCH the video here:
Zac’s mum, 33-year-old Hannah Oliver-Willets, said she would never be able to find words that express her gratitude to the people who helped pay for her son’s treatment.
She said: “They have given us potentially the gift of life, you cannot ask for anything better than that.
“That one deed, one donation to a cake sale, donating a pound or volunteering, that one deed, you put it together and suddenly you have got a life wrapped in a box you are about to give a parent.
“It is very emotional and very touching that people did what they did. To think they have given a boy the opportunity of growing older, they should be very proud of what they have done.”
'Thank you does not seem enough'
Zac’s father, Mark Garbett, said he was overwhelmed that they had managed to reach this point, after being faced with desperation only months ago.
He said: “Thank you does just not seem enough.
"Me and Hannah have both sat there and talked about it and said what can we do to say thank you, knowing it could never be enough.
"We have got a little boy that is cancer free, when the chances we were given were atrocious, abysmal.
“This is not something that happens. It is a miracle. If people want to do something they can do it and this just shows, the people have said they will sort this little boy out and they have done it for us.”
Zac underwent his treatment for Acute Lymphoblastic Leukaemia at the Children’s Hospital of Philadelphia in America.
The pioneering Car-T therapy, which is not available on the NHS, saw immune cells taken from his body, modified to fight cancer and re-infused.
The treatment was only possible after an incredible fundraising campaign.
People across Shropshire held events, collected sponsorship, donated pocket money, and took part in a Wear Red for Zac day to push towards the total.
The fund also received a donation from X Factor creator Simon Cowell, before a mystery donor pledged £100,000 to reach the target.
Zac will return to Philadelphia at the end of April for another bone marrow biopsy to see if he remains in remission, and then at three-monthly intervals for the next year.
In the meantime, he will receive intravenous immunoglobulin (IVIG) once a month to prevent infection.
After months of the stomach-churning worry that every parent fears, Hannah revealed how it was his rosy-red cheeks that first allowed her to hope the treatment was working.
She said: “He just looked so well. He had amazing rosy red cheeks, which he has not had for such a long time.
“As a mother I know every single blemish on his body, as a parent you know when something is not right, the colour is not right, and he looks so healthy now, and the colour of his cheeks makes such a difference.
“Going back nine months he had been like a ghost. I know from the outside it does not seem as much of a difference but to have colour in his cheeks is so significant.”
First day at school
Zac’s condition has improved to such an extent that he can now return to school, having only been able to manage a minimal number of days since he was supposed to start last September.
His father Mark Garbett said: “He can actually start school. He has only had a handful of days since he was supposed to start and he is going to be a normal little boy.”
Hannah and Mark said they could not stop smiling when they were told the news that tests showed Zac was cancer free.
Mark said: “When they told us it was just relief, they told us what we wanted to hear and it was real and just smiles.”
Hannah added: “We have gone from being in bereavement and devastation to the nation getting behind us, raising all this money and actually going and doing this. We have done it together.
“We have actually done it, it felt like such a long way away. Waiting for the T-cells to be engineered, that waiting felt like forever.
“I was always panicking. What if we wait too long and the cancer becomes unmanageable before he has a chance to have his Car-T cells put in, there is always that fear and now it is done.
“We can just breathe and plan and think about where we can take the children to have fun and all the nice things that other families do that are the norm, and we have not been able to do for such a long time.”
'He is amazing'
Hannah said that the difference in her son in the space of the 38 days since he was infused with the Car-T cells was incredible.
She said: “He is amazing, absolutely amazing, after the treatment he could not really walk very far and was sleeping a lot. That was the knock on effect of the Car-T. That was it getting to work wiping out cancer cells.
“He has now got his strength back.
“In fact I am struggling to get him to bed now! He has gone the opposite way, he is full of life and energy.”
Mark said that he now wants to see the treatment become available on the NHS.
He said: “This needs to be a front-line treatment in the UK. We need to move with the times and be real on how we treat people.
“The country needs to wake up and we need to push the NHS to do this, not just for the select few but for everyone.”