Whether donated human antibodies can protect premature babies from a common and potentially dangerous bacterial infection is under study at the Medical College of Georgia Children’s Medical Center.
In the last decade, better treatment of premature infants has translated into better survival rates for even the smallest babies, says Dr. Jatinder J.S. Bhatia, chief of the MCG Section of Neonatology and vice chair for clinical research of the Department of Pediatrics.
The average mortality for babies weighing 1-3 pounds is 10 percent, with survival rates at 20 percent to 40 percent for the lowest-weight babies and at 90-plus percent for 3-pound babies in neonatal intensive care units such as MCG’s.
Infections in the first days of life can essentially double that mortality rate, Dr. Bhatia says. Premature babies are particularly vulnerable to infection because their immune systems have not yet developed. In fact, the staphylococcal infection the study treatment targets lives harmlessly in an adult’s nose but causes blood infections and meningitis in babies, Dr. Bhatia says.
During a normal pregnancy, the mother shares protective antibodies with her baby, a sharing that’s accelerated in the last trimester of pregnancy and that can be augmented by breast-feeding. Unfortunately, premature babies are born too soon to get adequate levels of this immunoglobulin G to protect them until their own immune systems develop later in the first year of life, Dr. Bhatia says. Additionally, the medical care needed to save a premature baby’s life often includes invasive procedures, such as intravenous lines and catheters, which provide easy avenues for infection.
“Because infection is a risk factor for why the mother went into premature labor, the standard therapy for the first 48 hours is to start antibiotics,” says Dr. Bhatia, then to watch for signs of infection and results of ancillary tests and cultures. “We are quick to start and quick to stop,” he says of antibiotic therapy because of concern about resistant strains of bacteria that can develop when antibiotics are overused. In fact, some neonatal intensive care units – fortunately the MCG unit is not among them – have been hit by these strains necessitating even stronger antibiotics.
Dr. Bhatia wants to know whether a therapy of donor immunoglobulin, which more closely mimics the natural protection most babies receive, is a safe, effective option.
MCG is participating in a national study that includes giving four doses of the immunoglobulin, Veronateâ, intravenously over the first several weeks of life then comparing infection and mortality rates to those of babies who do not receive the therapy. About 2,000 babies will be enrolled nationally -- approximately 30 at MCG -- and half will receive placebo.
The new study also looks at infection rates of nosocomial candidemia, a hospital-borne blood infection. An earlier phase of the Veronateâ study, in which MCG also participated, showed surprisingly that some babies on the therapy had reduced rates of this common yeast infection, Dr. Bhatia says.
He noted that screened, purified human antibodies already are given to some cancer patients who have trouble fighting infections and to allergy patients.
He hopes one day immunoglobulin therapy can be used much like a vaccination to also protect fragile babies from common causes of infection.
So far, most parents approached about their babies’ participation in the study have been interested in exploring this protective option. “I tell parents that based on earlier phases of the study, the treatment may help their baby,” says Dr. Bhatia. “And, even if their child receives placebo instead of the study drug, his participation will help future generations of babies.”