March 2 (UPI) -- Antibody-based treatment instead of high-risk chemotherapy or radiation can help prepare patients with a condition known as "bubble boy disease" for a blood stem cell transplant, according to new research.
Researchers at the Stanford University School of Medicine have conducted a phase 1 clinical trial on the safety and efficacy of the treatment in two humans. Dr. Judith Shizuru, professor of medicine at the school, discussed the trial Tuesday at the annual meeting of Stanford's Center for Definitive and Curative Medicine.
In a university release, Shizuru said the antibody-based conditioning may be useful in combating other diseases as well, including cancer, type 1 diabetes, multiple sclerosis and lupus. For those with autoimmune diseases, the dangers of chemotherapy or radiation usually outweigh the benefits, she said.
Trial participants have a condition called severe combined immunodeficiency -- the proper name for "bubble boy disease" -- which is a genetic disorder that disturbs the normal development of immune cells. People with the condition are vulnerable to infections most people ward off easily.
Some patients live in a sterile environment. But many babies with SCID die within one year due to severe, recurrent infections unless they have undergone successful hematopoietic stem cell transplantation.
David Vetter, one of the first known SCID patients, was nicknamed "Bubble Boy" and was forced to live in a specially constructed sterile plastic bubble from birth in 1971 until he died at age 12, including at Baylor College of Medicine in Houston. Another patient, Ted Davita, was confined to a bubble from 1962 to 1980 in Maryland.
Knowledge of the condition grew significantly with the airing of The Boy in the Plastic Bubble, a 1976 TV movie inspired by Vetter and DeVita, who died as a child. John Travolta played "Tod," a teenage boy who lived in a sterile bubble due to illness.
Patients are commonly treated with stem cells and progenitor blood-forming cells to boost their immune response. But the treatments wear off over time because significant numbers of the healthy stem cells can't replace the diseased stem cells.
In a blood stem cell transplant, the patient's defective stem cells are replaced with chemotherapy or radiation, allowing normal blood stem cells from a donor to take their place.
"Physicians often choose not to give chemotherapy or radiation to young children with SCID because there are lifelong effects: neurological impairment, growth delays, infertility, risk of cancer, etc.," Shizuru said.
Researchers gave the participants an antibody to CD117, a cell surface marker found on blood and immune stem cells. In early data, the antibody's activity in humans is similar to what was observed in mouse studies -- it depletes genetically defective stem cells.
Participants have shown evidence that the donor stem cells are in place and producing immune cells, nine months afterward for one person and six months later for the other, Stanford researchers report.
The researchers plan to include infants with the disease in their trial because that's when negative effects of chemotherapy or radiation are acute and an effective treatment is most significantly needed.