It refused to discuss the specific case because of "patient privacy," but implied in its statement that Nora's parents did not understand the difference between the hospital's charges, and what the parents may have to pay for follow-up care "either at CHOP or back in the patient's home country."
Children's "estimates the costs of treatment in advance and seeks payment at the time treatment begins," the statement said. "Additional follow-up clinical treatments are sometimes necessary and can be administered over several years..."
"CHOP does not charge for this follow-up clinical treatment at the time of initial treatment. If the child is not further treated at CHOP, CHOP will never charge for the follow-up treatment. However, CHOP does explain those potential costs to patient families at the outset so they understand the financial issues they may be facing."
Even so, Nora's parents may not understand.
Nora's mother, Dana Atanosovska Situm, held a news conference in Croatia on Wednesday to say the family had obtained visas and was leaving for Philadelphia on Thursday - a day earlier than planned because Nora is so gravely ill. (A Serbo-Croatian-speaking journalist translated the conference for The Inquirer.)
Situm also thanked support groups, celebrities, individual donors, and Croatia's capital city, Zagreb, for helping to raise $837,000 - an astronomical sum in the economically distressed Balkan country.
She said Children's original bill was for $575,000, but $262,000 was added to cover five years of post-treatment care costs.
"I corresponded with the hospital until 2:40 a.m. this morning," she said. "It was a shock to see there were now two invoices. After going through this, I will never say anything against our [socialized] health system. What they have over there is just terrible."
The gene therapy, developed by scientists at the University of Pennsylvania, genetically modifies the patient's own T cells - the big guns of the immune system - to recognize and attack B cells, the blood cells that turn malignant in certain types of leukemia.
Only 10 adults and two children had been treated with the therapy as of December, but most have gone into temporary or lasting remission. That's a remarkable feat for any cancer therapy, but unheard of in the field of gene therapy, which has had few success stories despite decades of research.
One of the successes was Emily Whitehead, a 7-year-old pixie from Philipsburg, Pa. Like Nora, she had relapsed after repeated rounds of chemotherapy and was out of options when she went to Children's in April. She is now in remission.
The gene therapy is not a conventional drug, but a complex biological substance that is tailor-made over several weeks using deactivated viruses and cell cultures. Carl June, the lead Penn scientist, has said in the past that this production process alone costs about $20,000.
But the patient also requires many hospital procedures, tests, medications, and weeks of intensive care because the therapy typically has severe side effects.
Emily, for example, was on life support and nearly died before her doctors discovered that a new arthritis drug can counter those side effects.
She just marked her ninth month cancer-free, her father, Tom Whitehead, said Wednesday.
He guessed that Emily's care at Children's - covered by his health insurance and money from various charities and friends' fund-raising - had cost at least as much as the amounts cited in Nora's case.
On Children's Facebook page, Croatians expressed outrage over what they perceived as an eleventh-hour price increase.
"What is price for a child's life? Hypocrites!!!!" wrote one.
Another demanded: "Why can't you look beyond materialism and just HELP the ones in need?"
Jelena Vukas, a Croat working in Amsterdam and following the story in the Croatian media, e-mailed: "It's a little girl, it's a small nation. Croats are used to fighting. We've got a rich history of oppression from various regimes, and a tortured economy. When there's a crisis, the people try to stick together. I'm sure Nora's parents will raise money, it's just that with the unemployment and everyone struggling - there's not that much money up for collecting."
Contact Marie McCullough at 215-854-2720 or firstname.lastname@example.org.
Inquirer staff writer Stacey Burling and Berlin-based freelancer Claudia Himmelreich contributed to this article.