Zac Oliver, the British tyke whose worldwide following helped his family raise $840,000 for immunotherapy at Children's Hospital of Philadelphia, has no sign of his rare form of leukemia.
"Guess what, everyone? I have no cancer," Zac, 4, said in a video posted to YouTube on Friday, March 8, the day after he arrived back in his little home town of Broseley.
His mother, Hannah Oliver-Willets, thanked their supporters -- from school kids to celebrities such as music mogul Simon Cowell and professional footballer Jermain Defoe.
"Throughout this very difficult journey, we have been lucky enough to have witnessed the most astonishing and selfless acts by friends, family and strangers to help Zaccy," she posted on Facebook.
His father, Mark Garbett, messaged the Inquirer, "It's all been a whirlwind. Zac is cancer-free and doing amazingly well. We cannot thank the doctors enough for what they have done for us."
Zac was treated with Kymriah, the Novartis therapy that is genetically engineered from the patient's own disease-fighting T cells. In clinical trials of the breakthrough drug, about 80 percent of pediatric leukemia patients -- children who had exhausted conventional therapies -- went into remission within a month of treatment. However, about half of them relapsed and died within a year.
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Zac was diagnosed in May with an ultra-rare genetic subtype of acute lymphoblastic leukemia called near haploid. Chemotherapy did not completely eradicate the disease, in which immature white blood cells grow out of control. Doctors told his parents that the standard last-resort therapy -- a stem-cell transplant -- would offer little hope because his disease was so aggressive.
Confronted with the grim prognosis, Oliver-Willets, an occupational therapist, and Garbett, a heating contractor, began searching for another option. (The couple separated before Zac's birth, but Garbett is closely involved in his son's life.)
The parents discovered that England's national health care system was on the verge of making Kymriah available to children, but only after they had relapsed and exhausted standard leukemia treatments. Waiting for Zac to relapse, his parents believed, would be a death sentence.
CHOP doctors, who have discretion to use Kymriah earlier in the disease course, agreed to cover Zac's therapy and related care -- which can vastly inflate the drug's $475,000 price tag -- for $604,000.