We brought a newborn screening test to Washington to catch a rare immune disorder when babies are still healthy enough to be cured.
When Washington state started screening newborns for severe combined immunodeficiency (SCID) in 2014, it marked the triumph of Seattle Children’s five-year odyssey to bring the test to Washington – and a new chance at cures for the one in 40,000 babies afflicted with SCID.
SCID is a group of genetic disorders that leaves children with little or no immune system. Stem cell transplants can cure the disorders about 94% of the time in babies less than 3 and a half months old, according to a New England Journal of Medicine study that Drs. Lauri Burroughs and Suzanne Skoda-Smith contributed to. But SCID isn’t usually detected until babies get a serious infection when they’re 4 to 6 months old.
“The survival rate drops to around 50% at that point because the patients are too sick or too weak to do well during transplant,” Skoda-Smith says. “The key is to catch SCID before babies get ill.”
Screening all newborns
About five years ago, Skoda-Smith and Dr. Troy Torgerson proposed the Washington State Office of Newborn Screening add SCID screening.
“They were immediately on board, but they didn’t have the equipment or the expertise to do the SCID test – or the funding to pay for it,” Torgerson says.
Adding the SCID test to the newborn screening panel would increase costs by about $8 per patient, or approximately 8%. Michael Glass, who directed the state lab at the time, started the political process to add funding to the governor’s budget, which required legislative approval. Meanwhile, his staff figured out how to conduct the test.
“The state lab folks visited our lab and labs in Wisconsin, Massachusetts and New York to see how other states do SCID screening,” Skoda-Smith says. “Then they developed a terrific test of their own.”
Skoda-Smith, Torgerson and families affected by SCID converged on the state capitol over and over again to explain how newborn screening can save families from SCID’s devastating effects.
“One family opened by saying their child would still be alive if they were born in a state that screened for SCID,” Torgerson recalls.
He and his colleagues also addressed legislators’ concerns that Medicaid and insurance companies would suffer if they had to pay hundreds of thousands of dollars for stem cell transplants. Torgerson and Skoda-Smith explained that treating SCID after a child gets sick can be just as expensive as a transplant, with far worse outcomes.
The legislature approved the funding in 2013, making Washington one of about 30 states that screen for the disease. The state lab expects to identify one or two newborns with SCID per year, plus about a dozen children with less serious immune disorders. Those children will be referred to Seattle Children’s Blood and Marrow Transplant Program to confirm the diagnosis and for treatment.
“SCID diagnoses used to tear me apart because I had to tell so many parents that their baby probably wouldn’t pull through,” Torgerson says. “Now I can say we caught SCID so early that they have an excellent chance of being cured.”
A lifesaving protocol
Bone marrow transplant, and now gene therapy, are the only curative treatments that offer patients with SCID a chance at a normal life. In order to allow the transplanted cells to take hold, most babies require chemotherapy before transplant. Those who do usually get the drug busulfan to condition their body to accept the new cells.
The family of Ezra Dixon – the first newborn with SCID identified by Washington’s screening test – enrolled him in a clinical trial studying whether using treosulfan and fludarabine phosphate instead of busulfan is less toxic and easier for babies to withstand.
Burroughs designed the protocol that uses these drugs, and Seattle Children’s is one of only two places where patients can enroll in the trial. The FDA is evaluating treosulfan for approval and Burroughs envisions her protocol becoming standard treatment for nonmalignant diseases. “Treosulfan is widely used in Europe and about 90% of nonmalignant patients in our protocol have survived transplant, which is a huge improvement for babies who otherwise might not have much of a chance,” Burroughs says.
Ezra, who received a bone marrow transplant when he was 9 weeks old, is one of those kids. His cells engrafted within two weeks and his doctors expect him to be at full strength in time for summer.
“Before Ezra, I was always busy planning and worrying about the future,” says his mother, Rachel Dixon. “Now we cherish each moment.”
We can tell families we caught SCID early enough that their child has an excellent chance of being cured.
– Dr. Troy Torgerson